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X-linked Hydrocephalus / L1 Disease Spectrum
Congenital stenosis of the aqueduct of Sylvius
MASA Syndrome
CRASH Syndrome
These related neurological syndromes with X-linked inheritance are allelic and all due to mutation in the L1CAM gene. Congenital hydrocephalus and resultant macrocephaly associated with aqueductal stenosis may occur in isolation but is frequently associated with other features, including adducted thumbs, developmental delays including mental retardation, and spastic paraplegia. MASA syndrome includes
M
ental retardation,
A
phasia,
S
huffling gait, and
A
dducted thumbs. CRASH syndrome includes
C
orpus callosum agenesis/hypoplasia,
R
etardation,
A
dducted thumbs,
S
pastic paraplegia, and
H
ydrocephalus. There can be significant phenotypic variability within families, with some males being severely affected and diagnosed already during pregnancy, while others may have no macrocephaly and long survival. Five percent of females with a L1CAM mutation present with variable clinical symptoms.
Analysis is performed by bi-directional sequence analysis of the entire coding region (exons 1-28) including splice site junctions of the L1CAM gene. L1CAM mutations are present in 15-25% of males who have sporadic, isolated hydrocephalus. 74-90% percent of males with hydrocephalus, a positive family history, and at least one other feature of L1CAM disease show mutations in this gene. In females, where sequencing fails to identify a pathogenic mutation, targeted array CGH analysis with exon-level resolution (ExonArrayDx) will be performed to evaluate for a deletion or duplication of one or more exons of the L1CAM gene. Note, this testing requires a BLOOD specimen. Carrier detection in at-risk female relatives and prenatal diagnosis is also available.
For more details please review the Information Sheet linked below:
Information Sheet, including prices and CPT codes
Consent Document
Genetic Test Sample Submission Form (Test Requisition Form) including Payment Options
L1CAM, L1, MIC5, CAML1, agenesis corpus callosum, hydrocephalus, X-linked, adducted thumbs, spastic paraplegia, retardation, aqueductal stenosis, ventriculomegaly SPG1
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