AbstractWe report on a 3‐year‐old boy with hair abnormalities and a generalized bone dysplasia. He had very short, sparse hair and craniosynotosis. His stature, growth, and limb lengths were normal, as was his neurological development. While this phenotype has some resemblance to cranioectodermal dysplasia, the radiographic and hair abnormalities are different. Histological studies showed abnormalities in the internal root sheath of the hair follicle and the hair shaft. These findings define a new ectodermal dysplasia syndrome of unknown cause. © 1993 Wiley‐Lis