Confirm clinical diagnosis of thanatophoric dysplasia type 1 or type 2.
Polymerase Chain Reaction/Fragment Analysis
Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).
Transport 3 mL whole blood. (Min: 1 mL)
Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Background information for Thanatophoric Dysplasia, Types I and II (FGFR3) 13 Mutations
Characteristics: Micromelia, macrocephaly, short ribs and a narrow thorax; TD I has bowed femurs and TD II has straight femurs and a cloverleaf skull; death usually occurs from respiratory insufficiency within hours or days of birth.
Incidence: 1 in 20,000 to 50,000 births.
Inheritance: Autosomal dominant; arising from a de novo mutation.
Cause: Fibroblast growth factor receptor 3 (FGFR3) gene mutations.
Mutations tested: c.742C>T (R248C), c.746C>G (S249C), c.1108G>T (G370C), c.1111A>T (S371C), c.1118A>G (Y373C), c.2419T>G (X807G), c.2419T>A (X807R), c.2420G>T (X807L), c.2420G>C (X807S), c.2421A>T (X807C), c.2421A>C (X807C) and c.2421A>G (X807W) for TD I and c.1948A>G (K650E) for TD II.
Clinical Sensitivity and Specificity: 99 percent.
Methodology: Polymerase chain reaction (PCR) and single nucleotide extension followed by capillary electrophoresis.
Analytic Specificity and Sensitivity: 99 percent.
Limitations: Mutations other than those targeted in FGFR3 will not be detected; analytic sensitivity may be compromised by rare primer site mutations. Diagnostic errors can occur due to rare sequence variations.
Compliance Statement C: For human genetic inheritable conditions and mutations. This test was developed and its performance characteristics determined by ARUP Laboratories. The U. S. Food and Drug Administration has not approved or cleared this test; however, FDA clearance or approval is not currently required for clinical use. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions.
Counseling and informed consent are recommended for genetic testing. Consent forms are available online.
|Component Test Code*||Component Chart Name||LOINC|
|0051507||Thanatophoric Dysplasia I/II||75391-3|
|2001382||Thanatophoric Dysplasia I/II Specimen|
- Fetal Thanatophoric dysplasia mutation assay
- FGFR3 mutation assay