MASA syndrome
MASA syndrome is a rare X-linked recessive neurological disorder on the L1 disorder spectrum.[1]
Signs and symptoms[edit | edit source]
The acronym "MASA" stands for the four main signs and symptoms associated with the syndrome:(1) mental retardation (mild to moderate intellectual disability), (2) aphasia (delayed onset of speech), (3) shuffling gait, and (4) adducted thumbs.[2] Affected males may also have a variable dilatation(widening) of the third heart ventricle.[2]
Genetics[edit | edit source]
MASA syndrome has been associated with variants in the L1CAM gene.[1] The symptoms are typically more intensive in males, due to the fact that males inherit only one X-chromosome.
Diagnosis[edit | edit source]
A diagnosis can be made when the clinical features have been identified, mainly the four common signs and symptoms. This can then be confirmed by single-gene sequencing, where the L1CAM gene is examined for any possible variations.[2]
A diagnostic test prior-to-birth is possible and very reliable when the mother is a carrier of the diseased allele. First, it's necessary to determine the fetus' sex and then study the X-chromosomes inherited from the mother. The probability of transferring the variant X-chromosome to the descendants is 50% regardless of the sex of the fetus (as illustrated by the figure). Male descendants who inherit the varied X-chromosome will express the symptoms of the syndrome, on the other hand females who inherit the varied X-chromosome will become carriers of the mutated gene and will not show any symptoms or clinical features of the syndrome.[3][4]
References[edit | edit source]
- ↑ 1.0 1.1 Reference, Genetics Home. "L1 syndrome". Genetics Home Reference. Retrieved 2019-03-13.
- ↑ 2.0 2.1 2.2
- ↑
- ↑ "OMIM Entry - # 303350 - MASA SYNDROME". omim.org. Retrieved 2019-03-20.
External links[edit | edit source]
| Classification | |
|---|---|
| External resources |
- MASA syndrome at NIH's Office of Rare Diseases
- GeneReview/NIH/UW entry on L1 Syndrome
 | This genetic disorder article is a stub. You can help WikiMD by expanding it. |
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Contributors: Prab R. Tumpati, MD
