Saethre-Chotzen syndrome : TWIST Deletion/Duplication (MLPA)

TWIST sequencing is a molecular test used to identify variants in the gene associated with Saethre-Chotzen syndrome.

Turnaround Time

2 weeks

CPT Code(s)

81403

Cost

$350

Genes

Saethre-Chotzen Syndrome is one of the most common autosomal dominant disorders of craniosynostosis, affecting approximately 1/2000 newborn infants. It is characterized by craniofacial and limb anomalies. Mutations in the TWIST gene, which maps to chromosome 7p21-p22 are found in a majority of individuals with Saethre-Chotzen syndrome. Nonsense, missense, insertion, and deletion mutations of the TWIST gene have been found in studies of patients with Saethre-Chotzen syndrome.

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.

multiplex ligation-dependent probe amplification (MLPA)

Sequencing of the gene will detect mutations in >50% of individuals with Saethre-Chotzen syndrome.

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.

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 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.