P-01   EXCLUSION OF CANDIDATE GENES FOR A FAMILY FROM SAUDI ARABIA WITH AN AUTOSOMAL RECESSIVE FORM OF HYPOTRICHOSIS SIMPLEX

RC Betz, K. Al Aboud*, K. Al Hawsawi*, D. Al Aboud*, A. Al Githami*, G. Dewald, MM Nöthen. Department of Medical Genetics, University of Antwerp, Belgium; *Dermatology Section, King Faisal Hospital, Saudi Arabia.

Hypotrichosis simplex is a rare form of isolated alopecia. A generalized form affecting all body hair can be distinguished from a scalp-limited form (HSS). In both forms, patients are born with normal hair and show a gradual loss of hair beginning at the middle of the first decade leading to a complete loss of scalp or body hair by the third decade. All families described up to date follow an autosomal dominant mode of inheritance. Here, we report first molecular genetic data from a family with an autosomal recessive form of hypotrichosis simplex. The family originates from Saudi Arabia. The parents are third cousins. Four out of ten children are affected, six are unaffected. The affected siblings presented with progressive hair loss and thinning of scalp hair since early childhood. Two patients are almost bald, two show diffuse thinning of scalp hair. Furthermore, their body hair is sparse. No other associated abnormalities have been described. In a first step, we excluded linkage to the following candidate regions: hypotrichosis simplex (18p11), the CDH3 gene (16q22.1), the Vitamin D receptor (12q13.11), and the Keratin gene cluster (12q13.11), hypotrichosis simplex of the scalp (6p21.3), the Keratin gene cluster (17q11.2), and the hairless region (8p21-p22). We are currently performing a genome-wide linkage scan. The identification of a new gene for this isolated hairloss disorder will provide more insights in the genetic, molecular and cellular pathways that control hair growth.