Saethre-Chotzen Syndrome: TWIST1 Deletion/Duplication MLPA

TWIST1 Deletion/Duplication (MLPA) is a molecular test used to detect deletions and duplications in the gene associated with Saethre-Chotzen syndrome.

Turnaround Time

2 weeks

CPT Code(s)

81403

Cost

$500

Genes

• Saethre-Chotzen syndrome

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 TWIST1 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 TWIST1 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)

Copy number variants in the TWIST1 gene are identified in approximately 25% of individuals with Saethre-Chotzen syndrome.

The preferred sample type is 3-5 ml of peripheral blood collected in an EDTA (purple top) tube. Extracted DNA and saliva are also accepted for this test. Saliva samples must be submitted in an approved saliva kit. Contact the lab to receive a saliva kit or to have one sent to your patient.

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.