Osteopathia striata with cranial sclerosis: highly variable phenotypic expression within a family

We report a four‐generation family, with five individuals affected by osteopathia striata with cranial sclerosis (OS‐CS). The family illustrates the wide spectrum of gene expression in this autosomal dominant condition. Of particular note is the unusually severe expression in the proband, who exhibits virtually all of the reported associations of the syndrome. Proximal osteolysis of the fibula and congenital urological abnormalities, in the proband, and holoprosencephaly sequence, in the proband's sister, have not previously been described in the syndrome.