Clinical characteristics and genetic analysis of a Chinese pedigree affected with Alström syndrome

Abstract

To explore the clinical characteristics and genetic etiology of a Chinese pedigree affected with Alström syndrome. A pedigree with 5 members affected with Alström syndrome who had visited the First Affiliated Hospital of Zhengzhou University in February 2021 was selected as the study subject. Clinical data of the pedigree were collected, and peripheral venous blood samples were collected for the extraction of genomic DNA. Genetic testing was carried out for the eldest daughter and third son through whole exome sequencing (WES). Candidate variant was verified by Sanger sequencing and bioinformatic analysis. The eldest daughter (14 years old) and the third son (11 years old) both had congenital nystagmus, amblyopia, growth retardation and type 2 diabetes. WES revealed that both had harbored homozygous c.3538A>T (p.Lys1180*) variant of the ALMS1 gene. Sanger sequencing confirmed that the father, mother, and second daughter were all heterozygous carriers. Based on the Guidelines for Genetic Variation and the Technical Standards for Interpretation and Reporting of Primary Copy Number Variations, the variant was predicted as pathogenic (PVS1+PM2_Supporting+PP4). The homozygous c.3538A>T (p.Lys1180*) variant of the ALSM1 gene probably underlay the Alström syndrome in this pedigree, which has provided a reference for the clinical treatment.