A gene for freckles maps to chromosome 4q32-q34.

Freckles are numerous pigmented macules on the face commonly occurring in the Caucasian and Chinese population. As freckling is considered as an independent trait, no gene or locus for it has been identified to date. Here we performed genome-wide scan for linkage analysis in a multigeneration Chinese family with freckles. A maximum LOD score of 4.26 at a recombination fraction of 0 has been obtained with marker D4S1566. Haplotype analysis localized the freckles locus to a 16 Mbp region flanked by D4S2952 and D4S1607. We have thus mapped the gene for freckles to chromosome 4q32-q34. This will aid future identification of the responsible gene, which will be very useful for the understanding of the molecular mechanism of freckles.