1. ¹Shionogi Discovery Research Laboratories, Shionogi & Co., Ltd, Osaka, Japan
2. ²Division of Immunology and Embryology, Department of Cell Biology, Tohoku University School of Medicine, Sendai, Japan
3. ³Division of Dermatology, Department of Clinical Molecular Medicine, Kobe University Graduate School of Medicine, Kobe, Japan

Correspondence: Dr Tsuneaki Sakata, Shionogi Discovery Research Laboratories, Shionogi & Co., Ltd, Futaba, Toyonaka, Osaka 561-0825, Japan. E-mail: takeshi.yoshioka@shionogi.co.jp

⁴These authors contributed equally to this work.

Received 12 January 2006; Revised 16 May 2006; Accepted 23 May 2006; Published online 20 July 2006.

Abstract

DS-Nh mice and WBN/Kob-Ht rats are spontaneous hairless mutant rodent strains. These animals develop spontaneous dermatitis under normal conditions. The non-hair Nh and Ht phenotypes are inherited in an autosomal dominant fashion, and the Nh mutation possesses a high potency for penetration. We previously reported that genes involved in dermatitis and hairlessness did not segregate from each other. Here, we carried out genetic analysis to identify the genes responsible for these hairless mutations. An amino-acid substitution at the same position in one gene was detected in DS-Nh mice and WBN/Kob-Ht rats: Gly573 to Ser (Nh mutation) or Gly573 to Cys (Ht mutation), located in the transient receptor potential (TRP) cation channel subfamily V member 3 (TRPV3) gene. Mutated TRPV3 was expressed in skin keratinocytes of DS-Nh mice. Histopathological analyses revealed that mast cells in skin lesions were increased in both rodents compared to their age-matched parent strains, and that this may partially be due to hairlessness and dermatitis. We concluded that TRPV3 was the gene responsible for Nh and Ht mutations, and that mutation in TRPV3 possibly correlated with increased mast cell numbers.