Identification of LCA4 Locus in a Pakistani Consanguineous Kindred Suffering from Leber’s Congenital Amaurosis

Aims: To determine the disease locus involved in autosomal recessive Leber’s Congenital Amaurosis. Setting: Biomedical and Genetic Engineering Division, KRL, Islamabad. Patients and Methods: Five generations of a Pakistani consanguineous family suffering from congenital blindness (Leber’s Congenital Amaurosis) was studied. Genomic DNA was amplified across the polymorphic micro satellite markers. Polymerase chain reaction (PCR) products were separated by non-denaturing polyacrylamide gel electrophoresis. Alleles were assigned to individuals. LOD score calculations were done using the Cryllic and MLINK software program. Results: Molecular studies were done in 29 individuals of the family of whom 11 were blind and 18 were normal. Of eleven blind individuals six were males and five females. Linkage analysis for known loci of autosomal recessive LCA loci was carried out. Two point LOD score analysis with LCA 4 locus (17p13.1) resulted in maximum lod score (Z max) of 4.75 for marker D17S796 at θ=0. Conclusions: Significant linkage was found with LCA4 locus (17p13.1)