To study the distribution of the skin involvement in the cutis verticis gyrata and mental retardation (CVG-MR) syndrome skin thickness was determined radiographically on the flexor aspect of the forearm of ten patients with this syndrome. The skin of patients was thicker than that of normal controls but the difference was quite significant (1.4 +/- 0.4 mm versus 1.1 +/- 0.2 mm; p less than 0.05). When the analysis was applied to males only, the difference was statistically significant (1.5 +/- 0.3 versus 1.1 +/- 0.2 mm; p less than 0.01). There was no difference in skin thickness between the primary and miscellaneous forms of the syndrome. The findings suggest generalised skin involvement in the CVG-MR syndrome.