F20 A GENE FOR HYPOTRICHOSIS SIMPLEX OF THE SCALP MAPS TO CHROMOSOME 6P21.3

¹Betz R.C., ²Lee Y-A., ³Bygum A., ³Brandrup F., ⁴Bernal A.I., ⁴Toribio J., ⁴Alvarez J.I., ¹Kukuk G.M., ³Ibsen H.H.W., ³Rasmussen H.B., ⁵Wienker T.F., ²Reis A., ¹Propping P., ⁶Kruse R., ¹Cichon S., ¹Nöthen M.M.

¹Institute of Human Genetics and 5Institute for Medical Biometry, Informatics and Epidemiology, University of Bonn, Germany; ²Gene Mapping Center, Max-Delbrück Centrum Berlin, Germany; ³Department of Dermatology, University Hospital Odense, Denmark; ⁴Department of Dermatology, University of Santiago de Compostela, Spain; ⁶Department of Dermatology, University of Düsseldorf, Germany

Hypotrichosis simplex is a rare, autosomal dominant form of isolated alopecia. A generalized form affecting all body hair can be clinically distinguished from a scalp-limited form (HSS). Usually, patients with HSS present with normal hair at birth. They experience a progressive, gradual loss of scalp hair, beginning during the first decade and leading to almost complete alopecia by the third decade. After exclusion of candidate regions previously associated with hair loss disorders, we performed a genomewide linkage analysis in two Danish families and localized the gene to chromosome 6p21.3. This was confirmed in a Spanish family, with a total LOD score of 11.97 for marker D6S1701 in all families. The combined haplotype data identify a critical interval of 14.9 cM between markers D6S276 and D6S1607. Localization of the locus for HSS to 6p21.3 is a first step toward identification of the gene. The gene will give important insights into the molecular and cellular basis of hair growth on the scalp.