Further evidence of exclusion of linkage between type II autosomal dominant retinitis pigmentosa (ADRP) and D3S47 on 3q.

Linkage of the anonymous DNA marker D3S47 (CRI-C17) and autosomal dominant retinitis pigmentosa (ADRP) was tested in a large, extended family with type II (late onset) ADRP. D3S47 has been shown previously to be tightly linked to the RP locus in one family with type I (early onset) ADRP (McWilliams et al., 1989, Genomics 5: 619-622). Linkage between ADRP type II and D3S47 has recently been excluded in a single family (Ingelhearn et al., 1990, Genomics 6: 168-173). Results of our linkage analysis clearly establish that type II ADRP in our family is unlinked to D3S47. These findings support the hypothesis that type II ADRP is genetically distinct from type I ADRP.