Clark-Baraitser syndrome: report of a new case and review of the literature.

We describe the case of a boy with moderate mental retardation associated with tall stature, obesity, macrocephaly and typical facial features, characterized by a large 'square' forehead, prominent supraorbital ridges, broad nasal tip, prominent lower lip and minor dental anomalies. We think that our proband is affected by Clark-Baraitser syndrome, a rare X-linked mental retardation disorder, to date described only in five male subjects. We present a more complete definition of the clinical phenotype of the syndrome with particular attention to the behavioural aspect that, in combination with the body size and the dysmorphic picture, we think is distinctive for the Clark-Baraitser syndrome. We also summarize the mild features described in female relatives of the patients, as it could disclose a possible carrier condition and be of help with genetic counselling in the families with male patients, until a molecular test is available.