Microdeletion of 17q21.31 causes a recurrent recognizable dysmorphic syndrome. A further four patients with 17q21.31 microdeletions are reported here in whom an earlier diagnosis of cardio-facio-cutaneous syndrome was suggested. These patients have significant similarities of facial gestalt to earlier reported 17q21.31 microdeletion patients, but a striking feature that has not been emphasized previously is the large number of naevi and other pigmentary skin abnormalities that may be present. These features, together with a coarse facial appearance, relative macrocephaly and significant learning disabilities, were what had led to the earlier diagnostic suggestion of cardio-facio-cutaneous syndrome in each of these four cases.