Thanatophoric Dysplasia Type I: FGFR3 Targeted Analysis

Turnaround Time

2 weeks

CPT Code(s)

81404

Cost

$500

Genes

• Thanatophoric dysplasia type I

Thanatophoric dysplasia, types I and II both display micromelia, short ribs, small thorax and are usually lethal. Type I will display bowed femurs while type II will display straight femurs and a clover-leaf skull.

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.

FGFR3 mutations will be identified in 99% of patients with thanatophoric dysplasia, types I and II.

The preferred sample type is 3-5 ml of peripheral blood collected in an EDTA (purple top) tube. Extracted DNA, dried blood spots, 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.