Abstract
Abstract: :
Purpose: 1) To describe a new autosomal recessive juvenile cataract, 2) to exclude the known loci of autosomal recessive cataract. Methods: A consanguineous family segregating juvenile progressive cataract was ascertained from Portugal. 6 family members were clinically phenotyped. The patients had full eye examination, as well as complete photographic documentation, including slit lamp and Scheimpflug photography. Histopathologic examination of the cataractous lens was performed following cataract surgery. Blood samples were obtained after informed consent for DNA extraction and genotype characterization. Linkage and haplotype analyses were performed with markers of the three previously identified autosomal recessive cataract loci on chromosomes 3, 9 and 21 . Results: 2 out of 4 sibs were diagnosed with bilateral cataract, characterized by a shell-like inclusion in the cortex of the lens, associated with a pulverulent lamellar cataract of the foetal nucleus. Their parents were second cousins and had no signs of cataract. Best corrected vision ranged between 1/10 and 2/10 by the time of cataract surgery, which was performed during the third decade of life. Post-operative vision was limited to 7/10. Microscopic examination of the lens showed non specific alterations. Haplotype analysis did not support evidence for linkage of this family to the three previously identified loci. Conclusion: The described lenticular phenotype is potentially amblyogenic and represents a novel form of autosomal recessive cataract. In addition, the linkage data support further genetic heterogeneity for autosomal recessive cataract.
Keywords: 420 genetics • 338 cataract • 418 gene mapping