EPOS

European Paediatric Ophthalmological Society

Abstract Preview

Linkage analysis in a Liverpool family with dominantly inherited microcornea and cataract

SHAFIQ AYAD, WILLOUGHBY COLIN, PRISTON MEGAN, VINCENT ANDREA, HEON ELISE
¹Department of Paediatric Ophthalmology, Hospital for Sick Children, Toronto, Canada, ²Vision Science Research Program, Toronto Western Hospital Research Institute, Toronto, Canada

Purpose: Microcornea and coexisting cataract have been previously reported as a rare dominantly inherited familial trait in only six families, worldwide. We have recruited a seventh family and collected DNA from affected and unaffected family members for linkage analysis. Methods: A three generation family was identified with 11 affected members including 6 females and 5 males. A full ophthalmic examination performed on all family members included measurement of the axial lengths, using A-scan ultrasonography. The affected status was characterized with microcornea (largest diameter < 11 mm) and cataract (visually significant lens opacity). A panel of 9 candidate loci was selected for a preliminary linkage analysis. A minimum of 4 short tandem repeat polymorphism markers were selected per locus. Genotyping was performed using an automated sequencer and the two-point analysis was calculated using the MLINK program of the LINKAGE package 5.2 Results: A-scan measurements demonstrated that the microcornea and cataract was not part of a microphthalmic malformation (axial length less than 18.5 millimeters) in this family. Linkage analysis of these candidate loci is being completed and will be reported Conclusion: Microcornea and cataract, inherited in an autosomal dominant fashion, is rare. This family represents only the seventh such family reported with autosomal dominant inheritance pattern. The genes involved will play an important role in anterior segment development. With the results of linkage analysis, we will discuss the role of genes in anterior segment development, with the aim of expanding the current understanding of abnormal and hence normal ocular development.