Purpose: To map the gene for autosomal dominant cataracts (ADC) in an American white family of European descent.
Methods: Ophthalmic examinations and linkage analyses using a variety of polymorphisms were performed; two-point lod scores calculated.
Results: Affected individuals (14 studied) exhibited variable expressivity of embryonal nuclear opacities based on morphology, location within the lens, and density. This ADC locus to 12q13 was mapped on the basis of statistically significantly positive lod scores and no recombinations (theta(m) = theta(f) = 0) with markers D12S368, D12S270, D12S96, D12S359, D12S1586, D12S312, D12S1632, D12S90, and D12S83; assuming full penetrance, a maximum lod score of 4.73 was calculated between the disease locus and D12S90.
Conclusions: The disease in this family represents the first ADC locus on chromosome 12; major intrinsic protein of lens fiber (MIP) is a candidate gene.