NLGN4-Related XLMR
The Ambry Test: NLGN4-Related XLMR includes gene sequence analysis of the NLGN4/NLGN4X gene. Testing is also available for individual mutations in families in which a specific NLGN4 mutation has previously been identified.
PrintThe Ambry Test: NLGN4-Related XLMR includes gene sequence analysis of the NLGN4/NLGN4X gene. Testing is also available for individual mutations in families in which a specific NLGN4 mutation has previously been identified.
Next-Gen Sequencing of NLGN4 is also available as part of Ambry's XLMR Next-Gen SuperPanel™. It cannot be ordered separately.
Mental retardation (MR) involves a complex collection of clinically and genetically diverse disorders. Diagnosis of MR is typically based on three main criteria: onset of symptoms before the age of 18, intellectual abilities significantly lower than average, and reduced adaptive skills. Individuals with MR tend to struggle in areas including communication, health, interpersonal/social skills, leisure, safety, self-guidance and care, school performance, and work.
X-linked mental retardation (XLMR) is associated with more than 200 conditions linked to >90 genes on the X chromosome. XLMR affects approximately 1/600-1/1000 males, as well as a significant number of females. Mutations in these genes have been shown to be an underlying cause of mental retardation, which may or may not be associated with other congenital anomalies, developmental delay, autism, dysmorphism, and numerous genetic syndromes. One of the XLMR associated genes is NLGN4/NLGN4X.
The X-linked neuroligin 4 gene (NLGN4/NLGN4X) encodes an adhesion protein that participates in the formation, organization, and remodeling of neuronal synapses. The NLGN4 gene is located at Xp22.3 and contains 6 exons. Various types of mutations in NLGN4 have been implicated in autism spectrum disorders and/or mental retardation (Daoud, H. et al. Biol Psychiatry 2009;66:906-910).
NLGN4 genetic testing may be considered for any individual with idiopathic syndromic or non-syndromic mental retardation, developmental delay, and learning disabilities with or without congenital abnormalities.
Carrier testing for at-risk family members and prenatal testing are available for families in which a specific mutation in NLGN4 has been identified.
Genomic deoxyribonucleic acid (gDNA) is isolated from the patient’s specimen using a standardized kit and quantified by agarose gel electrophoresis. If gene sequence analysis is requested, all the analyzed regions of the gene are amplified through polymerase chain reaction (PCR) and the exact nature of the gene’s sequence variation(s) can be identified through double-stranded sequencing from sense and anti-sense directions. If specific mutation analysis is requested, only specific region(s) of DNA is (are) amplified by PCR and sequenced. NLGN4 exons 2-6 plus at least 20 bases into the 5’ and 3’ ends of all the introns are analyzed. The following sites are used to search for previously described NLGN4 mutations and polymorphisms: Human Gene Mutation Database (HGMD) and online search engines (e.g., PubMed).
| Test Code | Technique | CPT Codes |
|---|---|---|
| 3400 | NLGN4 Gene Sequence Analysis | 83891x1, 83894x9, 83898x8, 83904x16, 83909x16, 83912x1 |
| Technique | Days |
|---|---|
| NLGN4 Gene Sequence Analysis | 21-35 |