FYCO1 gene involved in congenital cataracts
MedWire News: Research has identified genetic mutations responsible for congenital cataracts.
The high frequency of FYCO1 mutations and the recessive inheritance pattern suggests that autosomal-recessive congenital cataracts are caused by loss of FYCO1 function.
"Our study provides a new cellular and molecular entry point to understanding lens transparency and human cataract," say J Fielding Hejtmancik (National Eye Institute, Bethesda, Maryland, USA) and colleagues in the American Journal of Genetics.
Congenital cataracts are a significant cause of vision loss worldwide, and are responsible for one third of the causes of blindness in infants.
Autosomal-recessive congenital cataracts are a clinically and genetically diverse group of disorders of the crystalline lens, according to the researchers.
So far, more than 40 loci for human congenital cataracts have been identified, with approximately 26 of these loci associated with mutations in specific genes.
Previous studies have identified FYCO1 as one candidate gene involved in the development of cataracts.
In this newest study, the group performed genome-wide linkage scans and mapping in unrelated consanguineous autosomal-recessive congenital cataract families.
In addition, 63 additional families were screened for mutations in FYCO1.
In 12 Pakistani families, as well as one Arab-Israeli family, the researchers identified mutations in the gene encoding FYCO1.
The FYCO1 protein is associated with the exterior of autophagosomes, and is known to mediate microtubule vehicle transport.
The researchers suggest that FYCO1 acts by degrading unwanted proteins in congenital cataracts.
"Autophagy is important for degradation of aggregated misfolded proteins, and accumulation of protein aggregates is a classic mechanism for light scattering and loss of lens transparency," report Hejtmancik and colleagues.
Autophagy is also associated with a variety of disease processes, including neurodegenerative diseases, cardiomyopathy, and Crohn's disease. In mouse models, the researchers also showed that FYCO1 is expressed in the embryonic and adult mouse lens.
The group adds that, given the frequency of the FYCO1 mutation in the Pakistani families studied, "it might be useful in genetic diagnosis," and could lead to new cataract treatments.
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