MASA syndrome: ultrasonographic evidence in a male fetus.

The recent identification of a common etiology among MASA syndrome (McKusick 303300), X-linked hydrocephalus (HSAS) (McKusick 307000) and other related neurological disorders, which had previously been considered distinct nosological entities, allowed us to diagnose MASA syndrome in a male fetus in a primigravida at the 29th week of gestation by sonographic signs of the MASA spectrum such as hydrocephalus and hypoplasia of corpus callosum. Indeed, the evidence of an X-linked neurological disease in the brother and the maternal uncle of the pregnant women enabled us to estimate a 25% risk of a male fetus being an affected hemizygote. The way in which a prenatal diagnosis, based on instrumental procedures, was reached is described since the authors were unable to perform, at the time of the observation, a molecular confirmation which was carried out only after birth.