Abstract
Purpose: :
To identify disease loci of autosomal dominant congenital cataract in five Sephardic North African Jewish families
Methods: :
A detailed medical history was obtained by interviewing family members and review of medical records. Patients were examined, blood samples were collected, DNA was isolated and cytogenetic studies were performed in one of the families. A whole genome scan was performed using microsatellite markers spaced at approximately 10cM intervals. For fine mapping 5 additional microsatellite markers were genotyped. Two–point lod scores were calculated using MLINK of the LINKAGE program package. After linkage was established, several positional candidate genes were assessed by PCR–based DNA sequencing.
Results: :
Two different cataract types have been found. In 4 Moroccan Jewish families: a new posterior polar cataract locus was mapped to an 11.3 interval between D14S980 and D14S1069 on chromosome 14q22–23. A maximum two–point lod score of 5.19 at theta=0, was obtained with the markersD14S274. The positional and functional candidate genes SIX1, SIX4, SIX6, OTX2, and ARHJ were excluded as the cause of cataract in these families.In a Libyan Jewish family: a novel reciprocal chromosomal translocation [t(3;5)(p22;pter)] was found to associate with embryonic cataract.
Conclusions: :
Two different novel loci/genes underlie clinically distinct types of Autosomal Dominant Congenital Cataract (adCC) in Sephardic North African Jews.
Keywords: gene mapping • cataract • linkage analysis