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HelpTest Code LAB3243 L1CAM Single Gene Analysis
Additional Codes
L1CAM Gene
Clinical System Name
L1CAM Single Gene Analysis
Synonyms
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.
Stability
| 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 |
Availability
| STAT | TAT |
|---|---|
| N | 3 w |
Performing Laboratory
GeneDx
207 Perry Parkway
Gaithersburg, MD 20877
Phone Number: (301) 519-2100
Department
Department: Send Outs
Phone Number: (206) 987-2563
Methodology
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:
Limitations:
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. |
Description
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).