144 Impaired Hair Growth and Structural Defects in Patients with Laron Syndrome (Primary IGF-I Deficiency)

R. Lurie1, D. Ben-Amitai1, Z. Laron2. Dermatology Unit Hair Clinic1, Endocr. Diabetes Res. Unit2, Schneider children’s Med. Ctr., Tel Aviv University, Israel.

Control of hair growth through IGF-I involves specific binding proteins (BPs), Which control IGF-I transport, efflux from the circulation and association with IGF-IR. The regulation of hair follicle growth through IGF-I is due, to the interaction of circulating and locally produced IGF-I on the hair follicles. Human hair growth in vitro showed that IGF-I maintain hair follicle in anagen (growing stage) and enter catagen (regression stage) if IGF-I is absent. Transgenic mice overexpressing IGF-I in the skin shown significantly increased vibrissa elongation. Laron syndrome (LS) primary growth hormone (GH) resistance has no GH signal transmission, and thus, no generation of circulating IGF-I is a unique model to study the effect of IGF-I on human hair. Patients with LS are born with spares hair, which grows slowly, resulting in large temporal recession throughout childhood and adult age. In adults the hair texture varies, and the patients develop alopecia of variable size, more pronounced in males. It is of note that despite decrease in the elastica of the dermis, early thinning and wrinkling of the skin, signs of early aging, graying of the hair delayed and reduce. We have investigated by light and scanning electron microscopy (SEM) the hair of 6 untreated adults LS patients(2M, 4F, aged 21-48 years), 5 IGF-I treated children with LS(4M, 1F, aged 8-13 years ). The hair have been plucked by rubber-protected forceps from the frontolaterl and Alopcia area of the scalp. The hair showed dysplastic and broken hair shaft and SEM revealed longitudinal grooves, torsion, and irregularities and impression of the hair shaft, as seen in pili torti, trichorrhexis nodosa pseudomonilethrix. This is the first report of hair structural defects in man caused by IGF-I deficiency and bears on the role of IGF-1 hair growth and development.