P8.105 AUTOSOMAL DOMINANT FAMILIAL LOOSE ANAGEN HAIR SYNDROME ASSOCIATED WITH ABSENCE OF VELLUS HAIR AND GENERALIZED HYPOTRICHOSIS - STUDY OF A FAMILY WITH 25 PATIENTS

Sung-Jan Lin, Shiuo-Hwa Jee, Hsien-Ching Chiu

Department of Dermatology, National Taiwan University Hospital and National

Taiwan University College of Medicine, Taipei, Taiwan

Objectives: To explore the clinical and pathological features of a tentative new genodermatosis featured by generalized hypotrichosis with easily pluckable scalp hair in a Taiwanese family.

Methods: 25 individuals from this family were enrolled into the study. Hair pull test, hair pluck test, laboratory examinations including blood biochemistry and complete blood counts and histopathology were performed. The hair was examined by light microscopy and scanning electron microscopy. A scoring system was used to evaluate the manifestations of hair defects in chronological order, nails, teeth, sweating, skin diseases and associated systemic diseases.

Results: The hair disorder appears to present in  an autosomal dominant inheritance in this family spanning four generations. Involved individuals have sparse scalp hair, eyebrows, and eyelashes starting at six months of age. Vellus hair can hardly be found over the glabrous body surface. Cleft upper lip is observed in one affected individual. Scalp hair can be easily and painlessly extracted before the age of four and the extracted hair is typical of loose anagen hair, showing rolled-back cuticle scales on a short segment of promimal hair shaft in scanning electron microscopy. The scalp hair increases in amount and length gradually later in childhood, and can no longer be easily extracted. In some cases, adequate coverage of scalp is not reached until adulthood. However, high percentage of loose anagen hair can still be revealed in a hair-pluck trichogram in adulthood. Hair inside nostrils, axillary hair, pubic hair, and mustache remain sparse in adulthood and  further reduced with age. The development of teeth, nails, and sweating are all normal. Histological findings show abscence of hair shaft  in atrichial skin.

Conclusions: The association of loose anagen hair syndrome with absence of body

vellus hair and generalized hypotrichosis has never been reported before. This syndrome can be a severe form of familial loose anagen hair syndrome or a new form of autosomal dominant genodermatosis.