CASE REPORT article
Front. Pediatr.
Sec. Genetics of Common and Rare Diseases
Volume 13 - 2025 | doi: 10.3389/fped.2025.1672911
De novo Missense Mutation in MYT1L Leading to Autosomal Dominant Intellectual disability 39 and Autism Spectrum Disorder: A Case Report
Provisionally accepted
- 1School of Traditional Chinese Medicine, Changchun University of Chinese Medicine, Changchun, China
- 2Diagnosis and Treatment Center for Children, The Affiliated Hospital of Changchun University of Traditional Chinese Medicine, Changchun, China
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Background: Autosomal dominant intellectual disability type 39 (MRD39; OMIM # 616521）is caused by heterozygous mutation in the MYT1L gene on chromosome 2p25.3. The MYTL1 encoded protein belongs to a novel class of cystein-cystein-histidine-cystein zinc finger proteins that function in the developing mammalian central nervous system. Case Summary: We report a 1-year-6-month-old girl presenting with global developmental delay (GDD) and autistic behaviors, demonstrating inability to stand independently, crawling mobility, poor response to name calling, and impaired joint attention. Initial developmental assessments yielded a Griffiths Mental Development Scale score of 57 and an ADOS-2 score of 11. Following 20 months of systematic rehabilitative training, the patient achieved independent ambulation, could follow simple commands, and produced phrases under 10 words, though suboptimal response to name calling and joint attention persisted. Re-evaluation showed a Griffiths score of 59 and an ADOS-2 score of 10. Whole-exome sequencing identified a de novo heterozygous missense variant in the MYT1L gene [c.1695G>T; p.(Arg565Ser)]. According to the American College of Medical Genetics and Genomics (ACMG) guidelines, this variant was classified as Likely Pathogenic based on criteria PM6 (de novo status) and PM2 (absence in population databases). Based on the concordant genotype and phenotype, the patient was diagnosed with MYT1L-related neurodevelopmental disorder (MRD39). Conclusion:We report a case of MYT1L-related disorder presenting with global developmental delay and features of autism spectrum disorder, associated with the previously documented but functionally uncharacterized c.1695G>T (p.Arg565Ser) variant. This case provides valuable clinical evidence supporting the pathogenicity of this variant and contributes to a deeper understanding of the phenotypic spectrum of MYT1L-related conditions.
Keywords: Autism Spectrum Disorder, Global developmental delay, Autosomal dominant intellectual disability type 39, MYT1L, Epilepsy
Received: 25 Jul 2025; Accepted: 09 Oct 2025.
Copyright: © 2025 Wang, Lin, Chen, Qi, Sun, Wang and Jiang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Shungzhu Lin, 61858@163.com
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