Targeted gene sequencing of FYCO1 identified a novel mutation in a Pakistani family for autosomal recessive congenital cataract.

Background: Congenital cataract is causing one-third of blindness worldwide. Congenital cataract is heterogeneous in its inheritance patterns. The current study is aimed to explore the unknown genetic causes underlying congenital cataracts.

Methods: Blood samples from affected and normal individuals of n = 25 Pakistani families identified with congenital cataracts were collected. Genomic DNA was extracted and Sanger sequencing was performed to identify novel pathogenic variants in the FYCO1 (MIM#607182) gene. Later structural bioinformatics tools and molecular dynamics simulations were performed to analyze the impact of these variants on protein structure and function.

Results: Sanger sequencing resulted in the identification of a novel splice site mutation (NM_024513.3: c.3151-29_3151-7del) segregating in an autosomal recessive manner. This novel variant was confirmed to be absent in the n = 300 population controls. Further, bioinformatics tools revealed the formation of a mutant protein with a loss of the Znf domain. In addition, we also found a previously known (c.4127 T > C; p.Leu1376Pro) mutation in four families. We also report a novel heterozygous variant (c.3419G > A; p.Arg1140Gln) in another family.

Conclusions: In conclusion, we report a novel deletion (NM_024513.3: c.3151-29_3151-7del) in one family and a frequent homozygous missense mutation (c.4127 T > C; p.Leu1376Pro) in four Pakistani families. The current research highlights the importance of autophagy in lens development and maintaining its transparency.