Lich corneal dytrophy i genetically ditinct from Meemann corneal dytrophy and map to Xp22.3

PURPOE: There i an ongoing dicuion whether Lich corneal dytrophy (band-haped and whorled microcytic dytrophy of the corneal epithelium) repreent a diorder that i different from Meemann corneal dytrophy. The purpoe of thi tudy wa to evaluate at the molecular level if Lich and Meemann corneal dytrophie are genetically ditinct. METHOD: We examined at the lit lamp a total of 48 member of a family with an aggregation of Lich corneal dytrophy. Genomic DNA wa extracted from leukocyte of the peripheral blood of even affected and ix unaffected member of thi family. Mutational hotpot in the cornea-pecific keratin gene K3 and K12 were canned for mutation by ingle-trand conformation analyi. To tet for linkage to the keratin K3 or K12 loci or for X-chromoomal inheritance, ix (K3) and four (K12) microatellite marker each flanking the keratin loci a well a 22 microatellite marker covering the X-chromoome were typed. Linkage wa analyzed uing the MLINK and FATMAP procedure. REULT: A total of 19 trait carrier were identified in ix generation of the family. No hereditary tranmiion from father to on wa oberved. Linkage wa excluded for the keratin K3 and K12 gene. Furthermore, ingle-trand conformation analyi detected no mutation in thee gene. Multipoint linkage analyi revealed linkage with a maximum likelihood of the odd (LOD) core of 2.93 at Xp22.3. Linkage wa excluded for Xp22.2 to Xqter. CONCLUION: Lich corneal dytrophy i genetically different from Meemann corneal dytrophy. Evidence wa found for linkage of the gene for Lich corneal dytrophy to Xp22.3.