LINKAGE OF A GENE FOR MACULAR CORNEAL-DYSTROPHY TO CHROMOSOME-16

Autosomal recessive macular corneal dystrophy (MCD) is a heterogeneous disorder leading to visual impairment. Sixteen American and Icelandic families (11 type I and 5 type II) were analyzed for linkage, by use of 208 polymorphic microsatellite markers. A significant maximum LOD s core (Z(max)) of 7.82 at a maximum recombination fraction (theta(max)) of .06 was found with the 16q22 locus D16S518 for MCD type I. In addi tion, a peak LOD score of 2.50 at a recombination fraction of .00 was obtained for the MCD type II families, by use of the identical marker. These findings raise the possibility that MCD type II may be due to t he same genetic locus that is involved in MCD type I.