1. ^*Institute of Human Genetics, University of Bonn, Bonn, Germany
2. ^†Department of Dermatology, University of Düsseldorf, Düsseldorf, Germany
3. ^‡División de Genética, CIBO, IMSS, Guadalajara, Mexico
4. ^§Department of Dermatology, University of Innsbruck, Austria

Correspondence: Dr Markus M. Nöthen, Institute of Human Genetics, University of Bonn, Wilhelmstr. 31, 53111 Bonn, Germany. Email:noethen@humgen.uni-bonn.de

Received 23 April 1999; Revised 22 July 1999; Accepted 20 August 1999.

Abstract

Papular atrichia is an autosomal recessive disorder characterized clinically by the occurrence of universal congenital alopecia and disseminated papular lesions. Recently, mutations in the human hairless (HR) gene have been reported in Irish and Arab Palestinian families with papular atrichia. We have studied two further kindreds with this clinical phenotype from other ethnic backgrounds. For mutation detection the complete coding region as well as exon-intron boundaries of the HR gene were sequenced. The first family is a Mexican family with clinically typical papular atrichia. Sequencing identified a homozygous deletion of 4 bp in exon 7 (2001delCCAG) leading to a premature stop codon in exon 8. The second family is a South Tyrolian family with affected individuals showing papular atrichia and retardation of bone age during childhood. All affected individuals were identified as homozygous for an AG transition at nucleotide position 2909 (exon 14) leading to an amino acid change of asparagine to serine in codon 970 (Asn970Ser). These data provide further evidence for the involvement of hairless mutations in papular atrichia. In addition, these findings suggest that the hairless protein is not only involved in hair development but also in the process of ossification during development.