Mapping of hereditary trichilemmal cyst (TRICY1) to chromosome 3p24‐p21.2 and exclusion of β‐ CATENIN and MLH1

Trichilemmal cysts (also named pilar cyst) derived from the outer root sheath of the deeper parts of the hair follicle can segregate dominantly, and are caused by a yet unknown gene. In order to identify candidate genes for this trait we have ascertained a Danish family with 38 persons (11 affected), and carried out a genome wide scan with 580 DNA micro‐satellite markers to identify the locus for a gene, which we termed TRICY1 (for trichilemmal cysts). We found tight linkage to D3S1277 (Z = 4.63; θ M = F  = 0.00), with flanking markers D3S2432 (Z = 1.59; θ M = F  = 0.08), and D3S3685 (Z = 2.69; θ M = F  = 0.08) spanning 10.3 Mb on chromosome 3p24‐p21.2. We sequenced two candidate genes previously reported in inherited hair defects, CTNNB1 and MLH1 but failed to detect mutations in exons and intron–exon bounders. © 2005 Wiley‐Liss, Inc.