Confirms a diagnosis of hypochondroplasia in individuals with clinical or radiological evidence of the condition.
- Patient Preparation
- Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B).
- Specimen Preparation
- Transport 3 mL whole blood. (Min: 1 mL)
- Storage/Transport Temperature
- Unacceptable Conditions
- Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Characteristics: Short stature, stocky build, large head, shortening of the proximal or middle segments of the extremities, short broad hands and feet, limitation of elbow extension, and mild joint laxity. Phenotype not evident in infancy, becomes apparent in childhood.
Inheritance: Autosomal dominant; usually arising from a de novo mutation.
Cause: 70 percent of cases result from an A or G nucleotide substitution for C at 1620 in the FGFR3 gene.
Methods: PCR and fluorescent resonance energy transfer.
Limitations: Mutations in FGFR3 and other than c.1620C>A or c.1620C>G will not be detected. Diagnostic errors can occur due to rare sequence variations.
Analytic Sensitivity and Specificity: 99 percent
Clinical Sensitivity: 70 percent
Counseling and informed consent are recommended for genetic testing. Consent forms are available online.
|Component Test Code*||Component Chart Name||LOINC|
|0051385||Hypochondroplasia (FGFR3) 2 Mutations|
|2001326||Hypochondroplasia (FGFR3), Specimen|
- FGFR3 molecular assay