Exclusion of RAI2 as the causative gene for Nance-Horan syndrome

Nance-Horan syndrome (NHS) is an X-Iinked condition characterised by congen ital cataracts, microphthalmia and/or microcornea, unusual dental morpholog y, dysmorphic facial features, and developmental delay in some cases. Recen t linkage studies have mapped the NHS disease gene to a 3.5-cM interval on Xp22.2 between DXS1053 and DXS443. We previously identified a human homolog ue of a mouse retinoic-acid-induced gene (RAI2) within the NHS critical nan king interval and have tested the gene as a candidate for Nance-Horan syndr ome in nine NHS-affected families. Direct sequencing of the RAI2 gene and p redicted promoter region has revealed no mutations in the families screened ; RAI2 is therefore unlikely to be associated with NHS.