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Test Code LAB3243 L1CAM Single Gene Analysis

Additional Codes

L1CAM Gene

Clinical System Name

L1CAM Single Gene Analysis


L1 syndrome
X-Linked Hydrocephalus with Stenosis of the Aqueduct of Sylvius (HSAS, Aqueductal Stenosis, X-linked)

L1 Cell Adhesion Molecule
MASA Syndrome (Mental Retardation, Adducted Thumbs, Shuffling Gait, and Aphasia)
SPG1 (X-Linked Complicated Hereditary Spastic Paraplegia Type 1)
X-Linked Corpus Callosum Agenesis

CRASH Syndrome

Sample Requirements

Preferred Specimen: Whole Blood

Container(s): Lavender Top/EDTA

Preferred Vol: 5.0 mL

Minimum Vol: 2.0 mL (1.0 mL for small infants)


Alternative Specimen: DNA

Container(s): Sterile Plastic Tube

Preferred Vol: 5 µg of purified DNA at a concentration of ≥50 ng/µL AND a volume of ≥100 µL


Alternative Specimen: Buccal Swab

Processing Instructions

Reject due to:

Spin: N

Aliquot: N

Temp: 2 - 8 C

Storage location: Refrigerate in CPA refrigerator Send Outs rack. Samples drawn on a Friday can be refrigerated until Monday shipment. Samples drawn on a Friday before a Monday holiday must have DNA extraction.


Off-site collection: Send whole blood refrigerated.


Specimen Type Temperature Time
Whole blood Room temp 3 d
Whole blood Refrigerated 7 d
Whole blood Frozen N
Extracted DNA Room temp 3-4 d
Extracted DNA Refrigerated 1 y
Extracted DNA Frozen Indefinitely



N 3 w


Performing Laboratory


207 Perry Parkway

Gaithersburg, MD 20877

Phone Number: (301) 519-2100


Department: Send Outs

Phone Number: (206) 987-2563


Method: In males, analysis is performed by bi-directional sequencing of all 28 coding exons and their
exon/intron splice junctions of the L1CAM gene. Large deletions of one or more exons are
detectable by sequencing in males; however, partial gene duplications would not be identified
by sequencing. Targeted array CGH analysis with exon-level resolution (ExonArrayDx) is
available as a reflex test to evaluate for a partial gene duplication. In females, sequencing
cannot detect large deletions or duplications, so ExonArrayDx is performed concurrently to
evaluate for a deletion or duplication of one or more exons of the L1CAM gene. Any variant
identified is confirmed by repeat analysis using sequencing, restriction fragment analysis, or
other methods, as appropriate.

Analytical Volume:


Reference Range

Interpretive report is provided.

Send Out Instructions

Reference Test Name: L1CAM Gene Sequencing & Del/Dup
Reference Lab Test Code: 552
Instructions: Ship via FedEx Priority Overnight. Saturday deliveries are accepted.



The phenotypic spectrum of L1 syndrome includes X-linked hydrocephalus with stenosis of the aqueduct of Sylvius (HSAS), MASA syndrome (Mental retardation, Aphasia [delayed speech], Spastic paraplegia [shuffling gait], Adducted thumbs), SPG1 (X-linked complicated hereditary spastic paraplegia type 1), and X-linked complicated corpus callosum agenesis. Males with HSAS are born with severe hydrocephalus, adducted thumbs, and spasticity; intellectual disability is severe. In less severely affected males, hydrocephalus may be subclinically present and documented only because of developmental delay; intellectual disability ranges from mild (IQ: 50-70) to moderate (IQ: 30-50).

Special Instructions



Test Info Sheet


Clinical Utility

GeneReviews: L1 Syndrome