English abstract
Autosomal recessive comca plana is characterized by a flattened comcal surface associated with hyperopia and various anterior segment abnormalities. Mutations have been detected in the keratocan gene (KERA), a member of the small leucine-rich proteoglycan family This project is carried out to characterize clinically and molecularly a consanguineous Omani Family in which four individuals are affected with comes plana Clinical ophthalmic examination, including vision cycloplegic refraction, slitlamp examination, intraocular pressure measurement (IOP), optic disc assessment, corneal keratometry, and A-scan ultrasonography to determine the axial length was performed on seven family members. Also, molecular analysis of KERA gene was performed on DNA from each family member. Clinical ophthalmic examination shows that all four affected individuals have an extreme flattening of the cornea. Anterior segment abnormalities included seleralization of the corea and central iris strands to the coreal endothelium. Molecular analysis shows that affected individuals were homozygous for a novel mutation in KERA. The sequence change was found in exon 2, which results in an asparagine to lysine change at codon 176. This amino acid change occurs within a highly conserved leucine rich repeat of keratocan.
