Martin-Bell syndrome in Greece, with report of another 47,XXY fragile X patient.

A cytogenetic investigation was carried out among 200 mentally retarded boys in Greece for the detection of the fragile X [fra(X)] syndrome. Thirteen patients were found to carry fra(X) (6.5%). Of those, six boys had a history of familial X-linked mental retardation, two had the phenotype of the Martin-Bell syndrome, four had only mental retardation of unknown etiology, and one was a mentally retarded patient with Klinefelter syndrome. The remaining 187 boys were fra(X) negative. Our findings emphasize the importance of early identification of this syndrome in the diagnosis and prevention, through proper genetic counselling, of mental retardation.