Identification of novel locus for autosomal dominant butterfly shaped macular dystrophy on 5q21.2-q33.2.

B utterfly shaped macular dystrophy was first described by Deutman et al. in 1970. It is characterised by bilateral accumulation of pigmented or yellowish material at the level of the retinal pigment epithelium. Lesions consist of 3–5 ‘‘wings,’’ which resemble the wings of a butterfly. Affected patients present with a subnormal electrooculogram and normal or slightly diminished visual acuity. The disease is relatively benign, but it can progress with age to chorioretinal atrophy in the parafoveal and peripapillary regions. Butterfly shaped macular dystrophy shares important similarities with age related macular degeneration—the most common cause of blindness in older patients. 4 In both diseases, abnormal deposition of lipofuscin like material at the level of the retinal pigment epithelium is found, which results in loss of the overlying photoreceptors. Butterfly shaped macular dystrophy has an autosomal dominant inheritance pattern. To date, it has been associated only with mutations in the peripherin/RDS gene. We ascertained members of the family with butterfly shaped macular dystrophy that was described originally by Deutman et al. in 1970, and we excluded peripherin/RDS as the causative gene in this family. In addition, we excluded the ROM-1 gene; four genes expressed in cone photoreceptors; all known non-syndromic macular, retinal pigment epithelium, and choroidal dystrophy loci; all known Leber congenital amaurosis loci; and all known non-syndromic congenital and stationary retinal disease loci. This study aimed to identify the locus responsible for butterfly shaped macular dystrophy in this family with a genomewide linkage scan.