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Test Code L1CAM UM L1CAM Sequencing

Important Note

L1CAM Sequencing (males)

Clinical System Name

L1CAM Sequencing


L1 syndrome
X-Linked Hydrocephalus with Stenosis of the Aqueduct of Sylvius (HSAS, Aqueductal Stenosis, X-linked)
MASA Syndrome (Mental Retardation, Adducted Thumbs, Shuffling Gait, and Aphasia)
SPG1 (X-Linked Complicated Hereditary Spastic Paraplegia Type 1)
X-Linked Corpus Callosum Agenesis


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).

Sample Requirements

Preferred Specimen: Whole Blood

Container(s): Lavender Top/EDTA, Yellow/ACD

Preferred Vol: 5 mL

Minimum Vol: 2 mL


Specimen: DNA

Container(s): Sterile plastic tube

Preferred Vol:  5,000 ng (5 µg) at concentration of 50 ng/µL

Minimum Vol:


Alternative Specimen: Oral Rinse (30-40 mL)|Buccal Swabs


Processing Instructions

Reject due to: Buccal brushes are not acceptable.

Spin: N

Aliquot: N

Temp: 2-8 C

Storage location: Refrigerate in CPA refrigerator Sendouts 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 9-10 w


Performing Laboratory



Department:  GeneDX, 207 Perry Parkway, Gaithersburg, MD 20877
Phone Number: (301) 519-2100

Reference Range

Interpretive report is provided.


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

Analytical Volume:


Special Instructions

Links to:




Clinical Utility

GeneReviews: L1 Syndrome

Send Out Instructions

Reference Test Name: L1CAM Gene Sequencing (Males)
Reference Test Number: 2551
Instructions: GeneDx accepts Saturday delivery. Whole blood specimens may be stored refrigerated for up to 7 days prior to shipping. Ship whole blood overnight via FedEx, ambient temperature.