ARX-Related Spectrum of X-Linked Intellectual Disability XLID : ARX Sequencing

Test Information

ARX sequencing is a molecular test used to identify variants in the gene associated with ARX-Related X-Linked Intellectual Disability XLID.

Turnaround Time

6 weeks

CPT Code(s)

81404

Cost

$1,000

Genes

Clinical Information

ARX is an X-linked disorder that can include non-syndromic intellectual disability or a broader phenotype including intellectual disability of West syndrome (infantile spasms), Partington syndrome (dystonic movements, ataxia and seizures) or X-linked hydrocephalus with ambiguous genitalia. ARX is localized to Xp21.1. Two mutations, a 24bp duplication and a 21bp insertion, in exon 2 of ARX account for a significant proportion of the alterations within the gene. Carrier females have no discernable phenotype.

Indications

Molecular testing is useful to confirm the diagnosis and to identify the disease causing mutations within a family to allow for carrier testing and prenatal diagnosis.

Methodology

Sanger Sequencing

Specimen Requirements

5 to 7 ml of peripheral blood collected in an EDTA (lavender top) tube is the preferred specimen type. The minimal blood needed for reliable DNA isolation is 3 ml. Extracted DNA, dried blood spots, and saliva are also accepted for this test.

Transport Instructions

The specimen should be kept at room temperature and delivered via overnight shipping. If shipment is delayed by one or two days, the specimen should be refrigerated and shipped at room temperature. Do not freeze the specimen. Samples collected on Friday can be safely designated for Monday delivery.

Prenatal Testing Information

Prenatal diagnosis is available if the familial mutations are known. Additional fees for cell culture and maternal cell contamination may apply. Maternal cell contamination studies are required for all prenatal molecular tests. Contact the laboratory prior to sending a prenatal specimen.

Have Questions Need Support?

Call our laboratory at 1-800-473-9411 or contact one of our Laboratory Genetic Counselors for assistance.
Robin Fletcher, MS, CGC
Kellie Walden, MS, CGC

Molecular Testing, Sanger Sequencing
One Mother's Story

One Mother's Story

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