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The Catalogue for Transmission Genetics in Arabs
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MASA Syndrome
Alternative Names
Mental Retardation, Aphasia, Shuffling Gait,
and Adducted Thumbs
Clasped Thumb and Mental Retardation
Thumb, Congenital Clasped, with Mental
Retardation
Adducted Thumb with Mental Retardation
Gareis-Mason Syndrome
Spastic Paraplegia Type 1
SPG1
Crash Syndrome
WHO International Classification of Diseases
Congenital malformations, deformations and
chromosomal abnormalities
Molecular Genetics
MASA syndrome is caused by mutation in the
gene encoding the neuronal cell adhesion
molecule L1 (LICAM). L1 plays a key role in
neuronal migration and neurite outgrowth by
mediation of axon bundling. It is a member of a
large class of immunoglobulin superfamily cell
adhesion molecules (CAMs), which mediate
cell-to-cell adhesion at the cell surface. L1CAM
is a 200-kDa transmembrane glycoprotein,
containing six Ig-like domains in the aminoterminal region, followed by five fibronectin
type III repeats, one transmembrane domain,
and a cytoplasmic domain.
Epidemiology in the Arab World
OMIM Number
303350
Mode of Inheritance
X-linked
Gene Map Locus
Xq28
Description
MASA syndrome is a rare neurological disorder
with an X-linked recessive mode of inheritance.
It is characterized by mental retardation,
adducted thumbs, shuffling gait, and aphasia.
Other symptoms and physical findings include
abnormal widening of cavities within the brain
and accumulation of excessive cerebrospinal
fluid in the hydrocephalus, mild short stature,
abnormally increased inward curvature of the
lower spine (exaggerated lumbar lordosis), and
other skeletal abnormalities. Brain imaging
provides evidence of dilated cerebral ventricles,
hypoplasia or agenesis of the corticospinal tract,
stenosis of the aqueduct of Sylvius, and
agenesis of the corpus callosum.
United Arab Emirates
Sztriha et al. (2000) described a boy who
presented with CRASH syndrome. He was born
to consanguineous parents from the United Arab
Emirates. The mother had six pregnancies.
One boy died at birth as a result of maternal
bleeding and another boy died after recurrent
diarrhea, fever, and convulsions at the age of 2
years. Development of the patient was delayed.
At 6 years of age, brain magnetic resonance
demonstrated a markedly reduced thickness of
the cerebral cortex, mainly in parieto-ocipital
areas.
References
Sztriha L, Frossard P, Hofstra RM, Verlind E,
Nork M. Novel missense mutation in the L1
gene in a child with corpus callosum agenesis,
retardation, adducted thumbs, spastic
paraparesis, and hydrocephalus. J Child
Neurol. 2000; 15(4):239-43.
Contributors
Ghazi O. Tadmouri: 6.6.2005
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