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At a glance

MASA is an acronym that stands for Mental retardation, Aphasia, Shuffling gait, and Adducted thumbs. Hydrocephalus associated with aqueductal stenosis. It is an extremely rare inherited disorder that is part of several medical conditions known as X-linked mental retardation (XLMR) Syndromes.


Clasped Thumb and Mental Retardation Syndrome; Gareis-Mason Syndrome; Spastic Paraplegia Type I Syndrome; Crash Syndrome; L1 Syndrome, Spastic Paraplegia Type I.


The acronym “CRASH” that stands for Corpus callosum, hypoplasia, Retardation, Adducted thumbs, Spastic paraplegia, and Hydrocephalus that has also been used to describe L1CAM-related disorders. It was originally proposed in 1995 by Dr Erik Fransen to describe the L1 Syndrome, but is no longer used.


Rare; it is responsible for approximately 10% of cases of hydrocephalus in males.

Genetic inheritance

X-linked recessive; locus at Xq28. Caused by a mutation in the gene for the neural L1 cell adhesion molecule (L1-CAM).


Seems to be associated with a mutation in L1-CAM, which is an axonal glycoprotein that is essential for normal development of the central and peripheral nervous systems during the fetal period and postnatally. However, the exact function of the L1-CAM protein is not fully understood.


Clinical picture; prenatal-onset hydrocephalus in males. Female carriers may have mild mental retardation or slightly adducted thumbs.

Clinical aspects

Varies from extreme macrocephaly following hydrocephalus caused by in utero stenosis of the sylvian aqueduct to absence of hydrocephalus with mental retardation and aphasia. The shuffling gait is secondary to spastic paraplegia. The presence of adducted thumbs (ie, flexed over the palms or “cortical thumb”) is pathognomic of this medical condition. The Patients affected have a small stature and lumbar lordosis is often present.

Precautions before anesthesia

Risk of raised intracranial pressure should be well assessed. Neurologic and cardiovascular status should be evaluated.

Anesthetic considerations

The anesthesia management should take into consideration to possible elevation of intracranial pressure. Other considerations will be determined by the underlying medical conditions and the surgical procedure intended.

Pharmacological implications

Avoid anesthetic agents with known potential to increase intracranial pressure.

Other conditions to be considered

  • X-Linked Hydrocephalus (Bickers Adams Syndrome): Characterized by severe hydrocephalus and caused by congenital stenosis of the aqueduct of Sylvius (HSAS). Other clinical features include macrocephaly, mental retardation, hypoplastic clasped or adducted thumbs, and/or spastic paraplegia. It is inherited as an X-linked recessive pattern. X-linked hydrocephalus and MASA (mental retardation, ...

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