MASA syndrome

MASA syndrome, also called CRASH syndrome and Gareis-Mason syndrome, is a rare X-linked recessive neurological disorder.

Symptoms
The acronym "MASA" describes the four major symptoms - Mental retardation, Aphasia, Shuffling gait, and Adducted thumbs. A more suitable name for this syndrome is "L1 syndrome". The disorder has been associated with mutations in the L1CAM gene. This syndrome has severe symptoms in males, while females are carriers because only one X-chromosome is affected. Affected males can't reproduce so their X-Chromosome isn't inherited. (The term "CRASH", for "corpus callosum hypoplasia, retardation, adducted thumbs, spastic paraplegia, and hydrocephalus" has also been used to describe L1CAM-related disorders.)

Diagnosis
A prenatal diagnostic is possible and very reliable when mother is carrier of the syndrome. First, it's necessary to determine the fetus' sex and, then, study X-chromosomes. In both cases, the probability to transfer the X-chromosome affected to the descendants is 50%. Males descendants will express the symptoms of the syndrome but females will be carriers.