REVIEW article

Front. Cell. Infect. Microbiol., 16 July 2025

Sec. Clinical Infectious Diseases

Volume 15 - 2025 | https://doi.org/10.3389/fcimb.2025.1615929

Clinical features of patients with fungal infections caused by CARD9 deficiency: a literature review of case reports

  • 1. Center for Infectious Diseases, West China Hospital, Sichuan University, Chengdu, Sichuan, China

  • 2. Intensive Care Unit, People’s Hospital of Dafang, Bijie, Guizhou, China

Abstract

Caspase recruitment domain containing protein 9 (CARD9) deficiency is an autosomal-recessive primary immunodeficiency disorder, undermines the body’s capacity to combat fungal infections. In recent years, the number of reported cases of fungal infections associated with CARD9 deficiency has been increasing. This study undertook a systematic review of case reports, incorporating 89 patients with CARD9 deficiency complicated by fungal infections. The findings demonstrated that the patient population predominantly consisted of young and middle-aged individuals (33.43 ± 19.12 years, range: 1-91), and the majority (52 patients, 58.43%) developed the disease during childhood or adolescence. Significant geographical variations were observed in the distribution of gene mutations. Specifically, the c.820dupG mutation was predominantly found in East Asia, while the c.865C>T mutation was primarily found North Africa. Regarding the clinical manifestations, the most frequently affected sites were the skin, central nervous system, and lymph nodes, and the principal fungal pathogens identified were Trichophyton and Candida. Correlation analysis indicated that c.883C>T increased the likelihood of Candida infection (p=0.008, OR=10.421, 95% CI 1.849-58.748), c.865C>T increased the probability of Trichophyton infection (p=0.038, OR=5.760, 95% CI 1.098-30.217) and dematiaceous fungi infection (p=0.005, OR=9.653, 95% CI 2.019-46.153). According to the types of mutations, nonsense mutation increased the risk of dematiaceous fungi infection (p=0.014, OR=6.212, 95% CI 1.453-26.556). Notably, a proportion of patients succumbed to the disease, and this was predominantly associated with infections of the central nervous system, blood system, and viscera. This underscores the importance of adequate antifungal therapy and long-term follow-up for patients with CARD9 deficiency-related fungal infections.

Introduction

CARD9 is a crucial adaptor protein in the innate immune response against fungal infections and its Online Mendelian Inheritance in Man (OMIM) number is 607212. Autosomal recessive CARD9 deficiency was first documented in 2009 within a consanguineous Iranian pedigree presenting with chronic mucocutaneous candidiasis (CMC) and dermatophytosis (). When the immune system detects fungal pathogens, CARD9 plays a pivotal role in the activated signaling pathways (Yazdi et al., 2023). Mutations in the CARD9 gene (NM_052813) result in CARD9 deficiency, which substantially compromises the body’s capacity to elicit an effective antifungal immune response. This disruption targets mechanisms primarily mediated by the C-type lectin receptor (CLR) and Toll-like receptor (TLR) families, which initiate defense responses against fungal pathogens (; ). In recent years, the number of reported cases of fungal infections associated with CARD9 deficiency has been gradually increasing. These infections present diverse clinical manifestations and can affect multiple organs and systems in the human body. Understanding the clinical features of patients with CARD9 deficiency-related fungal infections is of great significance for early diagnosis, appropriate treatment, and improving patient prognosis. However, due to the relatively rare study of CARD9 deficiency and the wide variety of fungal pathogens involved, the current comprehensive understanding of its clinical characteristics remains limited. Previous studies have been fragmented, and it is necessary to conduct a systematic review of case reports to summarize and analyze the existing data. This review aims to provide more perspectives by collecting and analyzing case reports from around the world. By systematically examining the clinical features, gene mutations, treatment strategies, and prognoses of patients with CARD9 deficiency-related fungal infections, we hope to provide valuable insights for clinicians and researchers in the fields of infectious diseases and immunology, facilitating better management of these complex cases.

Materials and methods

Literature search

The review process entailed a comprehensive exploration of all extant published literature on reported cases of fungal infections attributable to CARD9 deficiency. In the pursuit of relevant published works, a systematic search was conducted across the PubMed and China National Knowledge Infrastructure (CNKI) databases. The search terms employed were “CARD9”, “caspase recruitment domain deficiency” and “caspase recruitment domain containing protein 9”. Subsequently, the references of the initially selected papers underwent meticulous examination and screening. Articles of a review nature, those lacking detailed clinical data, and reports concerning patients without fungal infections were meticulously excluded from the analysis.

Data extraction

The following data were extracted: publication year, first author, age of the patient at the time of reporting, age of onset of the patient, patient’s gender, site of infection, fungal culture results, mutation sites, treatment regimens, treatment outcomes, whether the patient died of the disease, and patient origin. According to Melanized Fungi in Human Disease (), the dematiaceous fungi category was extracted. According to Fungal Infection: Diagnosis and Management, Fourth Edition (), superficial fungal infections are defined as only infections confined to the outermost layers of the skin, nails, hair, and mucous membranes. Deep fungal infections include the subcutaneous mycoses and the systemic mycoses, defined as infections of the dermis, subcutaneous tissues, and adjacent bones, as well as infections involving internal organs and vital structures. Define invasive fungal infection according to the Consensus Definitions of Invasive Fungal Disease from the European Organization for Research and Treatment of Cancer and the Mycoses Study Group Education and Research Consortium (). We distinguish the types of gene mutations through https://www.ncbi.nlm.nih.gov/clinvar.

Regarding the treatment outcomes, a subjective classification was employed, categorizing them into five distinct groups. The “not reported” category encompassed cases where treatment outcome information was unavailable. The “ineffective” category denoted cases in which, following systematic treatment, the patient’s general condition and the results of auxiliary examinations exhibited no signs of improvement. The “slightly improved” category referred to cases showing some degree of improvement, yet with a low likelihood of achieving complete clinical remission. The “partially improved” category applied to cases demonstrating improvement and a relatively high probability of attaining complete clinical remission. Finally, the “complete clinical remission” category signified cases where the patient’s fungal infection was eradicated, and organ functions were essentially restored.

Statistical analysis

The data extracted from the study were analyzed by the SPSS 27.0 software. The Mantel-Haenszel test was used to analyze the association between different factors, with sex as the stratification factor. When the sample size (n) is≥40 and all the theoretical count under the null hypothesis (T) are≥5, choose the Pearson chi-square test. When n≥40 and at least one theoretical count meets 1≤T<5, use the continuity-corrected chi-square test (Yates’ correction). When n<40 or T<1, select Fisher’s exact test. To explore further correlations, univariate and multivariate binary logistic regression analysis were conducted. In the multivariate regression analysis, we included age, gender, and different pathogens to eliminate confounding. The outcomes of this analysis were presented in terms of odds ratios (ORs) and their corresponding 95% confidence intervals (CIs).

Results

Patient basic information

In this study, a total of 58 articles were comprehensively incorporated, involving 89 patients with CARD9 deficiency, as detailed in Table 1. Among them, 48 patients were male (56.18%). The reported average age was 33.82 ± 18.90 years (range: 1-91), and 52 patients (58.43%) whose age of onset was less than 18 years old. The patients in this study originated from 17 distinct countries. As depicted in Figure 1, the countries with the highest 3 number of cases were China (34 cases, 38.20%), Algeria (12 cases, 13.48%), and Iran (10 cases, 11.24%).

Table 1

PatientKindredsReportd ageOnset ageGenderSite of infectionFungal culture resultsMutation siteType of mutationOther genetic mutationMethod of genetic testingTreatmentOutcomeDeathPatient originReferences
P1Kindred 1193MaleOral cavityCandidaHomozygous c.883C>T (p.Gln295Ter)NonsenseNot foundSanger sequencingKTCZComplete clinical remissionNoIran()
P2Kindred 1<18MaleOral cavity, CNSCandidaHomozygous c.883C>T (p.Gln295Ter)NonsenseNot foundSanger sequencingIneffectiveYesIran()
P3Kindred 15042FemaleSkin, vaginaCandida albicansHomozygous c.883C>T (p.Gln295Ter)NonsenseNot foundSanger sequencingNoIran()
P4Kindred 1FemaleOral cavity, vagina, skinHomozygous c.883C>T (p.Gln295Ter)NonsenseNot foundSanger sequencingNoIran()
P5Kindred 1<18MaleSkin-Homozygous c.883C>T (p.Gln295Ter)NonsenseNot foundSanger sequencingNoIran()
P6Kindred 1<18FemaleOral cavity, CNS-Homozygous c.883C>T (p.Gln295Ter)NonsenseNot foundSanger sequencingYesIran()
P7Kindred 1<18FemaleOral cavity, CNSCandidaHomozygous c.883C>T (p.Gln295Ter)NonsenseNot foundSanger sequencingIneffectiveYesIran()
P8Kindred 2756MaleSkin, Scalp, Nails, Lymph nodesTrichophyton violaceumHomozygous c.865C>T (p.Gln289Ter)NonsenseNot foundSanger sequencingNoAlgeria()
P9Kindred 2292MaleSkin, Scalp, Nails, Lymph nodes, CNSTrichophyton violaceumNot foundSanger sequencingGF+KTCZ+ITZIneffectiveYesAlgeria()
P10409FemaleSkin, Scalp, Nails, Lymph nodesTrichophyton rubrumHomozygous c.865C>T (p.Gln289Ter)NonsenseNot foundSanger sequencingNoAlgeria()
P11Kindred 3568MaleSkin, Scalp, NailsTrichophyton violaceumHomozygous c.865C>T (p.Gln289Ter)NonsenseNot foundSanger sequencingNoAlgeria()
P12Kindred 3348MaleSkin, Scalp, Nails, Lymph nodesTrichophyton violaceumNot foundSanger sequencingYesAlgeria()
P13Kindred 3418FemaleNailsTrichophyton violaceumHomozygous c.865C>T (p.Gln289Ter)NonsenseNot foundSanger sequencingNoAlgeria()
P14Kindred 44319MaleSkin, Scalp, Nails, Lymph nodes-Homozygous c.865C>T (p.Gln289Ter)NonsenseNot foundSanger sequencingNoAlgeria()
P15Kindred 44021MaleSkin, Perineum, Scalp, Lymph nodes-Homozygous c.865C>T (p.Gln289Ter)NonsenseNot foundSanger sequencingNoAlgeria()
P16Kindred 428MaleSkin, Scalp-Not foundSanger sequencingYesAlgeria()
P17Kindred 539MaleSkin, Scalp, Lymph nodesTrichophyton violaceumHomozygous c.865C>T (p.Gln289Ter)NonsenseNot foundSanger sequencingGF+KTCZPartially improvedYesAlgeria()
P18Kindred 537FemaleNails, Skin-Homozygous c.865C>T (p.Gln289Ter)NonsenseNot foundSanger sequencingNoAlgeria()
P19Kindred 640MaleSkin, Bone, Lymph nodesTrichophyton rubrumHomozygous c.301C>T (p.Arg101Cys)MissenseNot foundSanger sequencingNoMorocco()
P20Kindred 649FemaleScalp, Nails-Homozygous c.301C>T (p.Arg101Cys)MissenseNot foundSanger sequencingYesMorocco()
P21Kindred 7916MaleSkin, Scalp, Nails-Homozygous c.865C>T (p.Gln289Ter)NonsenseNot foundSanger sequencingNoTunisia()
P22Kindred 74412MaleScalp, NailsTrichophyton rubrumHomozygous c.865C>T (p.Gln289Ter)NonsenseNot foundSanger sequencingNoTunisia()
P23Kindred 7525FemaleSkin, Scalp, Nails, Lymph nodesTrichophyton rubrum and Trichophyton violaceumHomozygous c.865C>T (p.Gln289Ter)NonsenseNot foundSanger sequencingNoTunisia()
P24626MaleSkin, Scalp, Nails, Lymph nodesTrichophyton rubrum and Trichophyton violaceumHomozygous c.865C>T (p.Gln289Ter)NonsenseNot foundSanger sequencingNoTunisia()
P254130MaleCNSCandida albicansHomozygous c.271T>C (p.Tyr91His)MissenseNot foundWhole exome sequencingGM-CSF+VRCComplete clinical remissionNoFrance()
P262113MaleSkin-Compound c.191_192insTGCT (p. Leu64fsTer59) and c.472C>T (p.Gln158Ter)Frameshift and nonsenseNot foundWhole exome sequencingITZ+AMBIneffectiveNoChina(Wang et al., 2014)
P27176MaleSkin-Homozygous c.819_820insG(p.Asp274fsTer60)FrameshiftNot foundWhole exome sequencingITZ+AMBPartially improved, relapse after discontinuation of the drugNoChina(Wang et al., 2014)
P284320FemaleSkin-Homozygous c.819_820insG(p.Asp274fsTer60)FrameshiftNot foundSanger sequencingSurgical operation+ITZPartially improvedNoChina(Wang et al., 2014)
P296448MaleSkin-Homozygous c.819_820insG(p.Asp274fsTer60)FrameshiftNot foundSanger sequencingITZ+TBFPartially improvedNoChina(Wang et al., 2014)
P30243MaleSkin, Oral cavity, Scalp, NailsTrichophyton mentagrophytesHomozygous c.302G>T (p. Arg101Leu)MissenseNot foundSanger sequencingKTZ, ITZ, TBF, AMBSlightly improvedNoItalyAnete2015 ()
P3141.5FemaleCNSCandida albicansHomozygous c.883C>T (p.Gln295Ter)NonsenseNot foundSanger sequencingAMB+5-FC+VRC followed by long-term FCZComplete clinical remissionNoTurkey()
P324013MaleSkinTrichophyton rubrumHomozygous c.865C>T (p.Gln289Ter)NonsenseNot foundSanger sequencingPOSComplete clinical remissionNoEgypt()
P3385FemaleCNS, Liver,Exophiala dermatitidisHomozygous c.52C>T (p. Arg18Trp)MissenseNot foundSanger sequencingAMB+VRCIneffectiveFrance()
P342618FemaleBone, Skin, LungExophiala spiniferaHomozygous c.967_969delGAG (p. Glu323de)DeletionNot foundSanger sequencingIran()
P354236FemaleCNS, Vagina,Candida albicansHomozygous c.208C>T (p. Arg70Trp)MissenseNot foundSanger sequencingAMB +5-FC followed by long-term FCZComplete clinical remissionNoTurkey()
P3677FemaleSkin, CNS, Oral cavity, NailsCandida albicansHomozygous c.208C>T (p. Arg70Trp)MissenseNot foundSanger sequencingAMB +FCZPartially improvedNoTurkey()
P372817MaleColon, Ileum, CNS,Candida glabrataHomozygous c.104G>A (p. Arg35Gln)MissenseNot foundSanger sequencingFCZ, ITZIneffectiveNoIran()
P383734FemaleCNS, Oral cavity,Candida albicansHomozygous c.865C>T (p.Gln289Ter)NonsenseNot foundSanger sequencingAMB and 5-FC followed by long-term FCZComplete clinical remissionNoMorocco()
P393426MaleOral cavity, Esophagus, ColonCandida albicansHomozygous c.883C>T (p.Gln295Ter)NonsenseNot foundSanger sequencingAMB+POSSlightly improvedNoPakistan()
P40253MaleCNS, Oral cavity, SkinCandida albicansHomozygous c.883C>T (p.Gln295Ter)NonsenseNot foundTargeted ResequencingFCZ+AMB+CAS+G-CSF followed by long-term FCZComplete clinical remissionNoTurkey()
P412525FemaleEye, Bone, VaginaCandida albicansCompound c.1138G>C (p. Ala380Pro) and c.951G>A (p.Arg317Arg)Missense+ SilentNot foundWhole exome sequencingHigh-dose systemic antifungal agents followed by long-term KTZPartially improvedNoBritain()
P42459MaleCNS, Oral cavity, Abdominal cavity, Liver, Lymph nodesAspergillus, Candida.Homozygous c.883C>T (p.Gln295Ter)NonsenseSPAST mutationWhole exome sequencingLong-term KTZComplete clinical remissionNoEurope()
P431212MaleBlood vessel, Abdominal cavity, SkinAspergillus fumigatusHomozygous c.3G>C (p. Met1Ile)MissenseNot foundTargeted sequencingAntifungal drug treatment +surgical operation+double umbilical cord stem cell transplantationIneffectiveYesAfrica()
P443735FemaleSkin, Lymph nodes, Oral cavityCorynespora cassiicolaHomozygous c.191_192InsTGCT(p. Leu64fsTer59)FrameshiftNot foundWhole exome sequencingAMBSlightly improvedNoChina(Yan et al., 2016)
P454710FemaleSkin, Scalp, Lymph nodes, CNSTrichophyton rubrumHomozygous c.865C>T (p.Gln289Ter)NonsenseNot foundSanger sequencingLong-term ITZComplete clinical remissionNoAlgeria()
P463416FemaleSkin, Oral cavity, CNSPhialophora verrucosaCompound c.104>A (p. Arg35Gln)+c.241G>A (p. Glu81Lys)MissenseNot foundSanger sequencingGM-CSF+ITZ+TBFSlightly improvedNoChina(Zhang et al., 2017)
P47177FemaleCNS, Lung, Oral cavityCandida albicansCompound c.883C>T (p.Gln295Ter)Nonsense+ MissenseHeterozygote NLRP12 mutation (c.910C>T; p.
His304Tyr)
Targeted sequencingVRC+AMBIneffectiveYesTurkey()
P4888FemaleColonPrototheca zopfiiHomozygous c.781delG (p. Val261fs).FrameshiftNot foundWhole exome sequencingAMBPartially improvedNoTurkey()
P495843FemaleEye, CNSCandida albicansCompound c.184G>A and c.288C>TIntronic (splicing)Not foundSanger sequencingLong-term VRCComplete clinical remissionNoCanada()
P502826MaleSkinPhialophora americanaHomozygous c.819_820insG(p.Asp274fsTer60)FrameshiftNot foundSanger sequencingITZ+TBFNoChina()
P512412MaleSkin, Esophagus, BoneTrichosporon asahii, Candida albicansHomozygous c.819_820insG(p.Asp274fsTer60)FrameshiftNot foundSanger sequencingLong-term VRCComplete clinical remissionNoChina()
P522323MaleCNS, Skin, Lymph nodesExophiala dermatitidisHomozygous c.759dup (p. Lys254GlufsTer81)FrameshiftNot foundSanger sequencingAMB +VRCIneffectiveYesChina(Wang C. et al., 2019)
P533517FemaleSkin, Lymph nodes, CNSPallidocercospora crystallinaHomozygous c.1118G>C (p. Arg373Pro)MissenseNot foundWhole exome sequencingITZ+TBF+ surgical operationComplete clinical remissionNoChina()
P5475FemaleOral cavity, Nails, CNSCandida albicansHomozygous c.208C>T (p. Arg70Trp)MissenseNot foundSanger sequencingAMB + long-term FCZComplete clinical remissionNoTurkey()
P554646FemaleSkinMucor irregularisCompound c.692C>T (p. p.Ser231Phe) and c.905_907delTCT (p.Ser302del)Missense+ FrameshiftNot foundSanger sequencingAMB + long-term ITZComplete clinical remissionNoChina(Wang X. et al., 2019)
P562716FemaleSkinMicrosporum ferrugineumCompound c.883C>T (p.Gln295Ter) and c.1118G>C(p.Arg373Pro)Nonsense+ MissenseNot foundSanger sequencingITZ+TBFPartially improvedNoChina(Zhang et al., 2019)
P57109MaleCNS, Oral cavity, LiverCandida albicansHomozygous c.819_820insG
(p.Asp274fsTer60)
FrameshiftNot foundWhole exome sequencingG–CSF+FCZ+5-FCComplete clinical remissionNoChina()
P58129MaleColon, Esophagus, Oral cavityHistoplasma capsulatumCompound c.1204_1205insC (p. Cys402SerfsTer2) and c.1118G>C (p.Arg373Pro)Frameshift+ MissenseNot foundTargeted sequencingAMB followed by ITZComplete clinical remissionNoChina()
P593116MaleSkin, Nails, Lymph nodesTrichophyton rubrum, Trichophyton violaceum,
Aspergillus fumigatus, and Aspergillus flavus.
Compound c.271T>C (p.Tyr91His) and c.1269 + 18G>AMissense+ IntronicSTS gene (Xp22.3)Targeted sequencingG-CSF+GM-CSF+ multiple antifungal drugsSlightly improved, recurrent episodesNoThe United States of America()
P605632FemaleSkin, Lymph nodes, LungAspergillus nomius, Exophiala spiniferaHomozygous c.865C>T (p.Gln289Ter)NonsenseNot foundSanger sequencingRecombinant interferon γ-1b+ multiple antifungal drugsIneffectiveYesArgentina()
P614817MaleSkinTrichophyton rubrum, Candida albicans, Mucor irregularisCompound c.184 + 5G>T and c.951G>A (p.Arg317Arg)Intronic (Splice)Not foundWhole exome sequencingITZ+TBFComplete clinical remissionNoChina(Wang X. et al., 2020)
P625530FemaleSkinPhialophora expandaHomozygous c.819_820insG (p.Asp274fsTer60)FrameshiftNot foundAMB+ITZComplete clinical remissionNoChina()
P63<1<1MaleLung, Liver, Skin, Spleen, Lymph nodesTalaromyces marneffeiCompound c.1118G>C (p. Arg373pro) and c.610C>T (p.Asp204Asp)Missense+ SilentNot foundWhole exome sequencingVRCComplete clinical remissionNoChina()
P643227MaleSkin, Nails, Scalp, Lymph nodesTrichophyton rubrumHomozygous c.865C>T (p.Gln289Ter)NonsenseNot foundITZPartially improved, relapse after discontinuation of the drugNoSpain()
P6544FemaleCNS, Spleen, Lymph nodesExophiala dermatitidisCompound c.586A>G (p. Lys196Glu) and c.1118G>C (p.Arg373Pro)Missense+
Missense
Not foundTargeted
sequencing
AMB+VRC followed by TBFComplete clinical remissionNoJapan()
P662617FemaleSkinExserohilum rostratumc.1108C>T (p.Gln370Ter)NonsenseNot foundTargeted
sequencing
ITZ+5-FCComplete clinical remissionNoIndia()
P6737<18MaleCNS, Skin, Oral cavityCandida albicansHomozygous c.883C>T (p.Gln295Ter)NonsenseNot foundSanger sequencingMultiple antifungal drugsIneffectiveYesTurkey()
P6866MaleCNSAlternariaCompound c. 1526G>A (p.Arg509Lys) and c.586A>G (p.Lys196Glu)Missense+
Missense
Not foundWhole exome sequencingSurgical operation+ VRC+ AMB followed by long term VRCComplete clinical remissionNoChina()
P6955MaleLung, Liver, Spleen, Abdominal cavity, Bone marrow,Talaromyces marneffeiCompound c.440T>C(p.Leu147Pro) and c.586A>G(p.Lys196Glu)Missense+
Missense
Not foundMedical Exome SequencingAMB+VRCIneffectiveYesChina(You et al., 2021)
P705523FemaleSkinPhialophoraHomozygous c.819_820insG
(p.Asp274fsTer60)
FrameshiftNot foundExome SequencingAMB+ITZPartially improvedNoChina()
P713025MaleSkin, LiverTrichosporon asahiiHomozygous c.819_820insG
(p.Asp274fsTer60)
FrameshiftNot foundVRCPartially improvedNoChina()
P722823FemaleSkin, Nasal cavity, CNSAlternaria infectoriaHomozygous c.865C>T (p.Gln289Ter)NonsenseNot foundCandidate Gene SequencingAMB+ITZComplete clinical remissionNoTurkey()
P733828MaleSkinTrichophyton tonsuransHeterozygote c.596A>R (p. Lys196Glu)MissenseNot foundSanger sequencingPOSComplete clinical remissionNoChina()
P746867MaleSkin, Lung,Corynespora cassiicola, CladosporiumCompound c.106C>T (p.Gln36Ter) and c.1118G>C (p.Arg373Pro)Missense+
Missense
Not foundWhole exome sequencingVRCComplete clinical remissionNoChina(Wang et al., 2022)
P7565MaleLung, Spleen, Lymph nodes, Rectum, Colon, Bone marrowTalaromyces marneffeiHeterozygote c.820dupG (p. Asp274Ter)FrameshiftCD40LG mutation (c.346G>A)Whole exome sequencingVRC+AMBSlightly improvedNoChina(Yan et al., 2022)
P762120FemaleUrethraCandida glabratac.808-11G>IIntronicNot foundWhole exome sequencingVRC, MFG, CASComplete clinical remission, relapse after discontinuation of the drugNoChina()
P7723<18MaleSkin, Lymph nodes, Parotid glandTrichophyton rubrum, Microsporum canisNot foundSurgical operation+ GFComplete clinical remissionNoMorocco()
P781412FemaleLungAspergillus terreusHomozygous c.86G>A (p. Arg29His)MissenseNot foundWhole exome sequencingLong term VRCComplete clinical remissionNoIran()
P791716MaleSkin, CNSPrototheca wickerhamiic.820dupG (p. Asp274fs)FrameshiftNot foundVRC+AMBPartially improvedNoChina()
P804040FemaleSkin, Lymph nodesPurpureocillium lilacinumHomozygous c.820dupG(p.Asp274fs)FrameshiftNot foundVRCComplete clinical remissionNoJapan()
P811212MaleCNS, Oral cavityCandida albicansCompound c.1118G>C (p.Arg373Pro) and c.951G>A (p.Arg317Arg)Missense+ SilentNot foundWhole exome sequencingAMB+VRC+5-FC followed by VRC+5-FCComplete clinical remissionNoChina(Wang et al., 2023)
P822925MaleSkinPhialophora verrucosaCompound c.1118G>C (p.Arg373Pro) and c.820_821insG (p.Asp274fsTer60)Missense+ FrameshiftNot foundSanger sequencingPOSPartially improved, relapse after discontinuation of the drugNoChina(Zhang L. et al., 2023)
P836659FemaleSkinFusarium solaniae, Mucor irregularisHomozygous c.491delTFrameshiftNot foundWhole exome sequencingAMBComplete clinical remissionNoChina(Zhou et al., 2023)
P842113FemaleSkin, LungTrichosporon asahiiHomozygous c.820dupG (p. Asp274fs)FrameshiftNot foundExome SequencingVRC followed by ITZChina()
P854116FemaleSkinFusarium verticillioidesHomozygous c.819_820insG (p.Asp274fsTer60)FrameshiftNot foundWhole exome sequencingITZComplete clinical remissionNoChina(Zhang W. et al., 2023)
P868077MaleSkin, Lymph nodesTrichophyton rubrumHomozygous c.586A>G (p. Lys196Glu)MissenseNot foundWhole exome sequencingSurgical operation+ long term ITZComplete clinical remissionNoJapan()
P876363MaleBlood, Abdominal cavityT. marneffeic.35G>A (p.Ser12Asn)MissenseNot foundWhole exome sequencingCAS+VRC+AMBIneffectiveYesChina()
P8862FemaleCNSExophiala dermatitidisHomozygous c.820dupG (p. D274GfsX60)FrameshiftNot foundWhole exome sequencingVRC+5-FC+AMBIneffectiveYesChina()
P892424FemaleCNSCandida albicansHomozygous c.184 + 5G>TIntronicNot foundWhole exome sequencingCAS followed by FCZ+5-FCComplete clinical remissionNoChina(Zhou et al., 2024)

Statistical summary of the 82 enrolled patients’ information.

CNS, Central Nervous System; VRC, Voriconazole; ITZ, Itraconazole; AMB, Amphotericin B; TBF, Terbinafine; FCZ; POS, Posaconazole; CAS, Caspofungin; FCZ, Fluconazole;5-FC, 5 - Fluorocytosine; GF, Griseofulvin; MFG, Micafungin; KTCZ, Ketoconazole; G-CSF, Granulocyte Colony Stimulating Factor; GM-CSF, Granulocyte Macrophage Colony Stimulating Factor.

Figure 1

Gene variation distribution

As illustrated in Figure 2, this article comprehensively encompasses a total of 38 CARD9 gene mutations. The 5 most frequently occurring mutations are as follows: c.865C>T (18 cases), c.883C>T (14 cases), c.819-820insG (12 cases), c.1118G>C (9 cases) and c.820dupG (5 cases). The others segment in Figure 2 encompasses 27 distinct gene mutations, each with a frequency of only one instance. These mutations are c.472C>T, c.302G>T, c.52C>T, c.967_969delGAG,c.1138G>C,c.3G>C,c.241G>A,c.781delG,c.184G>A,c.288C>T,c.759dup,c.692C>T,c.905_907delTCT,c.1204_1205insC,c.1269 + 18G>A,c.610C>T, c.1108C>T, c.1526G>A, c.440T>C, c.596A>R, c.106C>T, c.808-11G>I, c.86G>A, c.491delT, and c.35G>A. The CARD9 gene and related gene mutations are shown in Figure 3. There are 6 types of gene mutations: nonsense (30 cases), missense (29 cases), frameshift (23 cases), deletion (1 cases), silent (2 cases), and intronic (6 cases) mutation.

Figure 2

Figure 3

Clinical features

This study enrolled patients with fungal infections involving 18 distinct anatomical sites, as depicted in Figure 4. All patients had deep infections. Among them, 32.82% were invasive infections and 67.18% were non-invasive infections. The 3 most commonly affected sites were the skin, central nervous system, and lymph nodes. In terms of taxonomic classification at the genus level, Trichophyton and Candida were the 2 most prevalent pathogens, as illustrated in Figure 5. Dematiaceous fungi (16 cases) including: Exophiala, Phialophora, Corynespora, Exserohilum, Alternaria, and Cladosporium. In addition to standard antifungal pharmacotherapy, diverse treatment modalities were employed. Colony-stimulating factor (CSF) was administered to 5 patients (P18, P33, P39, P50, P52), surgical interventions were performed on 6 patients (P21, P36, P46, P61, P70, P79), and 1 patient (P53) received recombinant interferon γ-1b treatment. According to the clinical outcomes, they were classified into the following 5 categories: not reported (22 cases, 24.71%), ineffective (14 cases, 15.73%), slightly improved (6 cases, 6.74%), partially improved (13 cases, 14.61%), and complete clinical remission (34 cases,38.20%). Unfortunately, 16 patients (17.98%) succumbed to the disease.

Figure 4

Figure 5

The relationship among genes, fungal pathogens and infection sites

To explore the relationships among various factors, we included the top 5 most frequent gene mutations (c.865C>T, c.819_820insG, c.1118G>C, c.883C>T, c.820dupG), gene mutations not in the top 5 (other mutations), Trichophyton, Candida, dematiaceous fungi, the top 3 most frequent anatomical sites (skin, CNS, lymph nodes), as well as invasive infections in the data analysis. Initially, the Mantel-Haenszel test was employed to assess the relationships between these factors. This statistical approach identified 18 significant associations, as detailed in Table 2: c.865C>T and Trichophyton, c.865C>T and dematiaceous fungi, c.865C>T and skin, c.865C>T and lymph nodes, c.865C>T and invasive infections, c.819_820insG and Trichophyton, c.819_820insG and lymph nodes, c.883C>T and Candida, other mutations and Candida, other mutations and skin, other mutations and central nervous system, other mutations and invasive infections, nonsense mutation and dematiaceous fungi, missense mutation and dematiaceous fungi, missense mutation and skin, missense mutation and invasive infections, frameshift mutation and Trichophyton, frameshift mutation and dematiaceous fungi. Subsequently, binary logistic regression analysis was carried out on these 19 identified associations to further quantify the relationships and estimate the strength of the associations, as presented in Table 3. The results indicated that c.883C>T increased the likelihood of Candida infections(p=0.008, OR=10.421, 95% CI 1.849-58.748), c.865C>T increased the probability of Trichophyton infections (p=0.038, OR=5.760, 95% CI 1.098-30.217) and dematiaceous fungi (p=0.005, OR=9.653, 95% CI 2.019-46.153). According to the types of mutation, nonsense mutation increased the risk of dematiaceous fungi infections (p=0.014, OR=6.212, 95% CI 1.453-26.556).

Table 2

Total patients (N=82)Trichophyton (n=20)Candida (n=18)Dematiaceous fungi (n=16)Skin (n=52)Central nervous system (n=26)Lymph nodes (n=24)Invasive infection (n=44)
Site of mutation/P-value
c.865C>T (n=18)<0.001b0.114b<0.001b0.047a0.121a0.006a0.002a
c.819_820insG (n=12)0.033b0.919b0.147b0.220b0.381b0.039b0.126a
c.1118G>C (n=8)0.208b0.818b0.319b1.000b1.000b0.897b0.368b
c.883C>T (n=14)0.267b0.005b0.388b0.072a0.068b0.634b0.167b
c.820dupG (n=5)0.439b0.505b0.580b0.520b1.000b0.970b0.450b
Other Mutations (n=42)0.739a0.042a0.150b0.004a0.036a0.222a0.027b
Type of mutation/P-value
Nonsense(n=26)0.059a0.349a0.004a0.692a0.908a0.299a0.052a
Missense(n=29)0.265a0.362a0.033a0.015a0.164a0.207a0.012a
Frameshift(n=23)0.001a0.070a0.013b0.218a0.082a0.140a0.248b
Deletion(n=1)1.000b1.000b1.000b1.000b1.000b1.000b1.000b
Silent(n=2)1.000b0.067b1.000b0.253b0.183b0.893b0.540b
Intronic(n=6)0.763b0.118b0.580b0.520b1.000b1.000b0.866b

The relationship between genes and infections.

Bold represents having statistical differences.

The “n” in parentheses indicates the number of patients with a positive result for this item.

The superscripts on the right side of the P-value represent different test methods. “a” denotes the Pearson test, and “b” denotes the continuity-corrected test (Yates’ correction).

Table 3

Project/AnalysisUnivariate analysisMultivariate analysis
P-valueOR (95%CI)P-valueOR (95%CI)
c.865C>T and Trichophyton<0.0017.636 (2.258-25.829)0.0385.760 (1.098-30.217)
c.865C>T and dematiaceous fungi<0.00118.543 (4.974-69.125)0.0059.653 (2.019-46.153)
c.865C>T and skin0.998
c.865C>T and lymph nodes0.0084.464 (1.482-13.445)0.412
c.865C>T and invasive infections0.0050.171 (0.051-0.581)0.937
c.819_820insG and Trichophyton0.998
c.819_820insG and lymph nodes0.999
c.883C>T and Candida<0.0018.585 (2.469-29.844)0.00810.421 (1.849-58.748)
Other mutations and Candida0.0180.309 (0.117-0.819)0.131
Other mutations and skin0.0050.238 (0.088-0.643)0.053
Other mutations and central nervous system0.0392.835 (1.054-7.627)0.644
Other mutations and invasive infections0.0313.066 (1.109-8.475)0.550
Nonsense mutation and dematiaceous fungi0.0065.100 (1.584-16.422)0.0146.212 (1.453-26.556)
Missense mutation and dematiaceous fungi0.0470.206 (0.043-0.983)0.103
Missense mutation and skin0.0150.303 (0.116-0.792)0.0590.304 (0.088-1.048)
Missense mutation and invasive infections0.0143.424 (1.286-9.113)0.147
Frameshift mutation and Trichophyton0.998
Frameshift mutation and dematiaceous fungi0.998

The results of binary logistic regression analysis.

Bold represents having statistical differences in Multivariate analysis.

Discussion

CARD9, a pivotal downstream component of pattern recognition receptors (PRRs), plays a central role in mediating a cascade of inflammatory responses against invasive fungi, bacteria, viruses, and parasites. Mutations in the CARD9 gene, which lead to reduced expression and functional impairment, are associated with an autosomal recessive primary immunodeficiency disorder. This genetic defect renders affected individuals highly susceptible to microbial infections. The PRRs/Syk/CARD9 signaling pathway, situated downstream of PRRs, is one of the most well-characterized and fundamental signaling cascades in the immune response (). CARD9-related C-type lectin receptors (CLRs) primarily include Dectin-1, Dectin-2, Dectin-3, and Mincle. Upon recognition of carbohydrate agonists, these CLRs recruit the tyrosine kinase Syk following Src kinase-mediated tyrosine phosphorylation of immunoreceptor tyrosine-based activation motif (ITAM)-like motifs (hem-ITAMs) or canonical ITAMs within their cytoplasmic tails (; ). Syk serves as a pivotal signaling mediator, coupling activated immunoreceptors to downstream pathways in immune cells. Following recruitment, Syk undergoes phosphorylation, triggering the activation of protein kinase Cδ (PKCδ). This, in turn, facilitates the recruitment and phosphorylation of CARD9 at Thr231, initiating downstream signaling cascades (Wang Y. et al., 2020).Animals with a genetic deletion of Card9 are susceptible to challenge with a variety of fungal species, including Candida albicans, Aspergillus fumigatus, Cryptococcus neoformans, and some rarer dematiaceous fungi ().

The demographic profile of patients with CARD9-deficiency-associated fungal infections predominantly comprises young and middle-aged individuals. A significant proportion, specifically 57.32% (47 cases) of the patients, experience disease onset during childhood or adolescence. Notably, there are distinct geographical variations in the distribution of CARD9 gene mutations. For instance, the c.820dupG mutation is predominantly observed in East Asia, a finding that aligns with previous research by Tomomasa et al. (). Additionally, our study identified that the c.819-820insG and c.1118G>C mutations are uniquely present in the East Asian region, with 819-820insG being reported exclusively in China. In the case series presented by Lanternier et al. (), all 12 patients with the c. 865C>T mutation were from Algeria, Morocco, and Tunisia. Over the past 12 years, 6 additional cases of this mutation have been reported, of which only 3 were from Spain, Turkey and Argentina, and the rest were from the above-mentioned North African countries, indicating that c.865C>T is mainly distributed in North Africa.

Fungal infections associated with CARD9 deficiency exhibit remarkable heterogeneity. The present study documented involvement of 18 distinct anatomical sites and identified 19 different genera of fungal pathogens. Among them, Candida and Trichophyton were the most isolated fungi. Meanwhile, fungal infections in CARD9-deficient patients showed a tendency toward severe invasiveness. According to the classification criteria of Classification and Nomenclature of Fungi, Fungal diseases (), all patients met the criteria for deep infection (involving at least the dermis and subcutaneous tissues). According to the definition of invasive fungal infection (), 32.82% of patients had definite invasive infections. Through correlation analysis, we found that the c.883C>T mutation significantly increased the likelihood of Candida infection, consistent with the analysis by Vaezi () and Dantas (). Moreover, the c.865C>T mutation was associated with an elevated probability of Trichophyton and dematiaceous fungi infection. A previous study () reported an association between c.819-820insG and disseminated phaeohyphomycosis (OR=2.42, 95%CI 1.84–3.2, p<0.001), and we did not find similar results.

The c.883C>T mutation in the CARD9 gene results from the substitution of cytosine (C) with thymine (T) at nucleotide position 883, leading to the premature formation of a stop codon. This reduces the short-term killing ability of CARD9-deficient neutrophils against unopsonized Candida albicans conidia (; ). The c.865C>T mutation, where the cytosine (C) at nucleotide position 865 is replaced by thymine (T), results in a premature stop codon. This mutation inhibits the release of inflammatory cytokines such as IL-6, IL-1β, and IL-17A, potentially serving as the underlying mechanism for Trichophyton infections (; ). This may explain the different pathogen susceptibilities associated with the two gene mutations. Dematiaceous fungi have been reported to cause subcutaneous and invasive infections, including chromoblastomycosis, phaeohyphomycosis, and mycetoma (). A study investigating the response to pathogenic dematiaceous fungi in Card9-knockout mice found that the inability to control these fungi was associated with a lack of Th17 differentiation and reduced levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and IL-17A in footpad homogenates (Wu et al., 2016). Previous research has not explored the relationship between mutation types and pathogens. We found that nonsense mutations increased the risk of dematiaceous fungi infections, yet the c.883C>T mutation, a relatively frequent nonsense mutation, did not exhibit this association. This discrepancy may be related to epidemiological differences. Although there is limited epidemiological data on dematiaceous fungi in Africa, a study on chromoblastomycosis prevalence, showed that Africa has the second-highest incidence after South America, while the c.883C>T mutation is absent in both regions.

Among the 82 patients included in this study, 13 succumbed to the disease. The majority of these fatal cases were associated with infections of the central nervous system, blood system, and/or viscera. This poor prognosis can be attributed, at least in part, to the reduced effectiveness to antifungal medications, which is a consequence of genetic defects in these patients. The prognosis of CARD9 patients is associated with co-existing mutations in other genes, some of which may exhibit synergistic effects. For example, co-mutations in the DOCK8 gene can lead to severe fungal infections (). The genetic heterogeneity of inborn errors of immunity and diagnostic delays in atypical cases lead to significant morbidity and mortality. Establishing a definitive genetic diagnosis is crucial for patient management (). Among the patients included in this study, 28.05% (23/82) of the patients underwent whole exome sequencing. Only 4 cases were found to have mutations in other genes: P35 (SPAST mutation) (), P40 (NLRP12 mutation) (), P52 (STS gene mutation) (), and P68 (CD40LG mutation) (Yan et al., 2022). The latter 3 gene mutations are associated with infections, and in these 3 patients, the disease is more severe and the treatment is more difficult. Granulocyte colony stimulating factor (G-CSF) and granulocyte macrophage colony stimulating factor (GM-CSF) exert pleiotropic effects on the innate immune system by enhancing the function of human neutrophils (). While their efficacy has been demonstrated in individual case reports (; ), large-scale clinical trials are still lacking. Nevertheless, they represent valuable salvage treatment options for patients who do not respond adequately to conventional antifungal therapy.

In conclusion, CARD9 deficiency should be considered in the differential diagnosis of patients presenting with progressive fungal infections of unknown etiology. Early initiation of antifungal treatment is crucial for improving patient outcomes, and long-term prophylactic treatment and regular follow-up are essential components of comprehensive management strategies.

Limitations

  • Our judgment of the patients’ clinical outcomes was subjective and only represented their conditions at that time, which might lead to a certain degree of bias.

  • There was no subjective classification of anatomical sites, such as the scalp and skin. However, for the integrity of the data, we directly extracted the sites stated in the articles. This might have some impact on the results.

  • Limited by the low prevalence of CARD9 deficiency, the statistical results may not reflect the true situation, especially for the interpretation of OR values.

  • This study did not include all CARD9 patients. It only included case reports and case series, and excluded patients without detailed clinical data and those with non-fungal infections.

Conclusion

In the contemporary landscape of medical research, there has been a burgeoning focus on non-HIV-associated opportunistic infections, which has emerged as a crucial area of investigation due to their increasing prevalence and clinical significance. This study retrospectively analyzed 82 patients with CARD9 deficiency complicated by fungal infections and found significant differences in clinical symptoms, fungal pathogens, and gene mutation sites. It provides potential relationships between gene mutations, pathogens, infection sites, and regional distributions, aiming to enhance the understanding of this disease.

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Author contributions

CT: Methodology, Writing – original draft, Data curation, Software. YL: Software, Writing – original draft, Data curation. JL: Investigation, Writing – review & editing. XL: Supervision, Writing – review & editing.

Funding

The author(s) declare that no financial support was received for the research and/or publication of this article.

Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Generative AI statement

The author(s) declare that no Generative AI was used in the creation of this manuscript.

Publisher’s note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

References

Summary

Keywords

CARD9 deficiency, fungal infection, gene mutation, clinical features, review

Citation

Tang C, Liu Y, Long J and Lv X (2025) Clinical features of patients with fungal infections caused by CARD9 deficiency: a literature review of case reports. Front. Cell. Infect. Microbiol. 15:1615929. doi: 10.3389/fcimb.2025.1615929

Received

07 May 2025

Accepted

30 June 2025

Published

16 July 2025

Volume

15 - 2025

Edited by

Andrew L. Snow, Uniformed Services University of the Health Sciences, United States

Reviewed by

Anne Puel, Institut National de la Santé et de la Recherche Médicale (INSERM), France

Rabab Elsayed El Hawary, Cairo University, Egypt

Donald C. Vinh, McGill University Health Centre, Canada

Updates

Copyright

*Correspondence: Xiaoju Lv,

†These authors have contributed equally to this work and share first authorship

Disclaimer

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.

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