4 weeks
CPT Code 
Test Code 
Test Methods 
Deletion/Duplication analysis
Specimen Types Accepted 
Cultured Cells
Extracted DNA
If sending saliva, 2 kits are required.

L1 syndrome is the most common cause of congenital hydrocephalus and accounts for about 5-10% of males with congenital hydrocephalus. The phenotypic spectrum of L1 syndrome, which can range from severe to mild,  includes X-linked hydrocephalus [OMIM#307000], MASA syndrome [mental retardation, aphasia, shuffling gait and adducted thumbs, OMIM#303350] and X-linked corpus callosum agenesis [OMIM#304100]. In less severely affected males, hydrocephalus may be subclinically present and only documented because of developmental delay.  Intellectual disability ranges from mild to moderate. Intra- and interfamily phenotypic variations have been reported.

Mutations in the L1CAM [OMIM#308840] gene are a cause L1 syndrome. The majority of mutations in L1CAM are private (unique to each family) and all types of disease-causing mutations have been identified: nonsense, frameshift, splice-site and missense mutations. L1CAM codes for the neural L1 cell adhesion molecule and is involved in cell-to-cell adhesion at the cell surface.