AUTHOR=Cai Tao , Huang Jieting , Ma Xiuwei , Hu Siqi , Zhu Lina , Zhu Jinwen , Feng Zhichun 

TITLE=Case Report: Identification of Two Variants of ALG13 in Families With or Without Seizure and Binocular Strabismus: Phenotypic Spectrum Analysis

JOURNAL=Frontiers in Genetics

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2022.892940

DOI=10.3389/fgene.2022.892940

ISSN=1664-8021

ABSTRACT=Background: Genetic causes in most affected children with intellectual disability and/or development delay remain unknown. 
Methods: To identify potential variants responsible for these disorders, we recruited 161 affected families and performed whole exome sequencing and associated bioinformatics analysis. 
Results: In the present study, we report the identification of variants in the ALG13 gene in two of the families. In family 1, a known pathogenic missense variant (c.23T>C; p.V8A) of ALG13 was identified in a boy and his mother of family 1. In family 2, a novel missense variant (c.862C>G; p.L288V) of the same gene was identified in the affected boy and his phenotypically normal mother. Genotype-phenotype correlation analysis by comparing reported 29 different variants showed that three major phenotypes, including various seizures/epilepsy, intellectual disability and development delay (such as growth, speech and motor, etc.) are present in most affected individuals. However, other phenotypes, such as strabismus and absence of seizure in our second patient, are not reported if any, which may represent a unique case of X-linked recessive nonsyndromic disorder caused by a mutation in ALG13. 
Conclusions: We identified two missense variants in ALG13 in a cohort of 161 families with affected individuals diagnosed as intellectual disability and/or development delay. A novel c.862C>G mutation, may represent a case of X-linked recessive.