Trichorhinophalangeal syndrome with low expression of TRPS1 on epidermal and hair follicle epithelial cells.

Trichorhinophalangeal syndrome (TRPS) is an autosomal-dominant congenital hair loss disease characterized by sparse and slow-growing scalp hair, craniofacial and skeletal abnormalities, pear-shaped nose, thin upper lip, brittle and thin toenails, and bilateral brachydactyly of the big toes. We report a case of TRPS1 exhibiting these clinical features with a novel heterozygous single nucleotide substitution in exon 3 of the TRPS1 gene. By immunohistochemical analysis of a biopsied specimen of the patient's alopecia lesion, we found for the first time that the expression level of TRPS1 was markedly reduced in the epidermis and the outer root sheath of hair follicles as compared to a normal subject. In addition, higher expression of phospho-Stat3 was found consequent to the loss of TRPS1 in the outer root sheath.