FLNA-Related Disorders : FLNA Sequencing

Test Information

FLNA sequencing is a molecular test used to identify variants in the gene associated with FLNA-Related Disorders/Otopalatodigital Spectrum Disorders.

Turnaround Time

6 weeks

CPT Code(s)

81479

Cost

$1,500

Genes

Clinical Information

There are several different phenotypes that have been associated with mutations in the FLNAgene.

FLNA mutations have been reported for the otopalatodigital spectrum disorders which include OPD type 1 & type 2 (OPD1 & OPD2), frontometaphyseal dysplasia (FMD) and Melnick-Needles syndrome (MNS). Males are usually more severely affected than females, but females present with variable expressivity. While the primary manifestation is skeletal dysplasia, males may also have a range of congenital anomalies. The most severe types are lethal in males. Normal intelligence is common except for in males with OPD2.

Mutations in the FLNA gene have also been associated with X-linked periventricular heterotopia. This disorder is generally lethal in males and affected females present mid-teens with seizures. This is a neuronal migration disorder in which brain imaging should be used to help establish the diagnosis. Affected females may also have cardiovascular findings, strabismus, psychiatric disorders or learning problems.

There is also an X-linked periventricular heterotopia, Ehlers-Danlos variant. In addition to the heterotopias, these patients have hyperflexible joints, and aortic dilatation or aneurysms.

FLNA mutations have also been reported in cases of X-linked cardiac valvular dysplasia in males characterized by mitral and/or aortic valve regurgitation. Female carriers are asymptomatic.

X-linked chronic idiopathic neuronal intestinal pseudoobstruction is a result of abnormal gastrointestinal motility with recurrent symptoms. All reported affected individuals have been male.

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

Detection

Otopalatodigital spectrum disorders have variable detection depending on the subtype. There are genotype-phenotype correlations with these disorders and specific regions of the gene. Sequencing will detect a mutation in 43% of OPD1, 69% of ODP2, 57% of FMD and almost all patients with MNS.

Sequencing of FLNA will detect a mutation in 98-100% of females with periventricular heterotopia when there is a family history, but only 26% of females will have a mutation when there is no family history.

There are not clear clinical detection rates for the other, rarer, phenotypes associated with mutations in FLNA.

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 or there are clinical features identified via ultrasound suggestive of a diagnosis in the fetus. 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
Meet Reggie Roper

Meet Reggie Roper

Reggie has been part of the GGC family for over 18 years. He has short stature, webbing of his hands, pulmonary stenosis, seizures and hydrocephalus along with developmental delay. He carried an initial diagnosis of cardiofaciocutaneous (CFC) syndrome; however, as genetic testing advanced, GGC made the diagnosis of Noonan-like syndrome with loose anagen hair by identifying a mutation in the SHOC2 gene. He is also an active participant in the Greenwood Community Theatre's Penguin Project. "GGC is...

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