Genetic linkage analysis of a Chinese family with freckle / 中华皮肤科杂志

ABSTRACT

Objective To report a three-generation Chinese family with freckle and to make a genetic linkage analysis in this family.MethodsGenetic linkage analysis was carried out in this family using microsatellite markers distributed over chromosome 4q and 1.Two-point logarithm of odds(LOD)scores were calculated using the Linkage program package(version 5.1),and haplotype was analyzed with Cyrillic version 2.01 software.Results Freckle was inherited in an autosomal dominant pattern with a penetrance of99.9% in this family;linkage to chromosome 4q was ruled out however,supportive evidence was obtained for linkage to microsatellite markers D1S2635 and D1S2844 in chromosome 1q with a maximum LOD score of 1.50.Haplotype analysis in this family localized the locus of freckle to a 12 Mb region flanked by D1S2624 and D1S2799.Conclusions Freckle is a genetically heterogeneous disorder.The causative gene may be located in a 21.2 cM region on chromosome 1q22-24.