Novel CRYGC Mutation in Conserved Ultraviolet-Protective Tryptophan (p.Trp131Arg) Is Linked to Autosomal Dominant Congenital Cataract

• Published in: International journal of molecular sciences Vol. 24; no. 23; p. 16594
• Main Authors: Delas, Flora, Koller, Samuel, Feil, Silke, Dacheva, Ivanka, Gerth-Kahlert, Christina, Berger, Wolfgang
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01.12.2023
• Subjects: Age; Cataracts; congenital cataract; conserved tryptophan; CRYGC; crystallin; Genes; Genetic testing; Genetics; Genomes; Genomics; Mutation; Proteins; UV damage; whole exome sequencing; United States > US; CRYGC; congenital cataract; UV damage; crystallin; whole exome sequencing; conserved tryptophan
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms242316594

Congenital cataract (CC), the most prevalent cause of childhood blindness and amblyopia, necessitates prompt and precise genetic diagnosis. The objective of this study is to identify the underlying genetic cause in a Swiss patient with isolated CC. Whole exome sequencing (WES) and copy number variation (CNV) analysis were conducted for variant identification in a patient born with a total binocular CC without a family history of CC. Sanger Sequencing was used to confirm the variant and segregation analysis was used to screen the non-affected parents. The first de novo missense mutation at c.391T>C was identified in exon 3 of on chromosome 2 causing the substitution of a highly conserved Tryptophan to an Arginine located at p.Trp131Arg. Previous studies exhibit significant changes in the tertiary structure of the crystallin family in the following variant locus, making prone to aggregation aggravated by photodamage resulting in cataract. The variant can be classified as pathogenic according to the American College of Medical Genetics and Genomics (ACMG) criteria (PP3 + PM1 + PM2 + PS2; scoring 10 points). The identification of this novel variant expands the existing knowledge on the range of variants found in the gene and contributes to a better comprehension of cataract heterogeneity.