Trichorhinophalangeal syndrome (TRPS) comprises a distinctive combination of hair, facial and bony abnormalities with variable expression. A 20-year-old man with TRPS was seen because of marked androgenetic alopecia. Scanning electron-microscopic studies of the hair revealed flattened hair with an elliptoid transverse section pattern. Mechanical behavior of the hair was abnormal with a significant increase in the viscous parameter, indicating a decreased intermolecular bridging within the keratin matrix. The dermatologist confronted with premature or marked alopecia in young adults should always consider the possibility of an underlying congenital syndrome involving the hair and prompt further investigation.