We report a case of Costello syndrome, which is an uncommon multisystemic condition with cutaneous manifestations on the palms and soles. In the literature there are 29 cases described, all the studies are published in the genetic literature with a few exceptions. We add a further case associated with impaired glucose tolerance. The diagnostic clinical signs are impressive, and highly characteristic. Cutaneous manifestations are: loose skin of the hands and feet "washer woman's hand", hyperkeratosis palmoplantaris, curly or sparse hair, acanthosis nigricans, papillomata nasi. Coarse, progeroid facial features with a bulbous nose, feeding difficulties in infancy, cardiac involvement with cardiomyopathy or conduction defect, and in our case impaired glucose tolerance also presented. Postnatal growth retardation, mental retardation, and a distinctive friendly personality is characteristic. Hyperextensible fingers with broad distal phalanges and joint contractures were observed, and peroneal hypertonicity required treatment by Achilles tendon lengthening. The decreased glucose tolerance is interesting in the view of the acanthosis nigricans. No storage disease and no chromosomal abnormality were observed. Only in one case is a balanced translocation described in the literature.