LINKAGE OF AUTOSOMAL-DOMINANT IRIS HYPOPLASIA TO THE REGION OF THE RIEGER SYNDROME LOCUS (4Q25)

Iris hypoplasia is an autosomal dominant disorder which is frequently associated with glaucoma, This glaucoma is usually resistant to medica l therapy and can lead to blindness, A large family of Scandinavian de scent with a five generation history of iris hypoplasia was studied, F ifteen individuals were found to have iris hypoplasia, nine of whom ha d associated glaucoma, In an attempt to identify the chromosomal locat ion of the disease-causing gene, this family was genotyped with short tandem repeat polymorphisms (STRPs) known to map to loci previously as sociated with glaucoma. The juvenile glaucoma locus at 1q25 and a cong enital glaucoma locus on 6p were both statistically excluded, However, significant linkage was demonstrated at the Rieger syndrome locus at 4q25. The highest observed LOD score was 3.70 (theta = 0) and was obta ined with marker D4S1616., Three recombination events were observed in affected individuals that together demonstrate that the disease-causi ng gene lies between markers ACT3E03 and D4S1611, an interval of simil ar to 7 cM. These results suggest that autosomal dominant iris hypopla sia and Rieger syndrome are allelic.