New Search

Laboratory Test Directory

Skeletal Dysplasia, FGFR3 Gene Characterization


Name Method Department Units
Skeletal Dysplasia Sequencing
Send Out Genetics

Specimen Requirements

Whole blood

Container Type Container Size Specimen Volume

Purple tube (EDTA)

6 mL 5 mL

Yellow tube (ACD)

8 mL 5 mL

Room temperature - 4 day(s)
Refrigerated - 1 week(s)

Specimen Preparation

  • Do not centrifuge
  • Keep at room temperature
  • Do not freeze

Reasons for Rejection

  • Wrong collection tube
  • Delayed or improper handling
  • Frozen specimen
  • Clotted specimen
  • Centrifuged specimen


This test is for blood only. Order XMIS for amniocytes/fibroblasts.

Germline missense mutations in the fibroblast growth factor receptor 3 gene (FGFR3) have been found in patients with achondroplasia, hypochondroplasia, and thanatophoric dwarfism. A mutation at codon 380 of FGFR3, which results in a substitution of glycine to arginine, is seen in >98% of patients with achondroplasia. Hypochondroplasia is associated with a mutation at codon 540 which results in a substitution of asparagine to lysine; this mutation is found in about 60-70% of the patients. Thanatophoric type I (curved femurs and variable cloverleaf skull) is genetically more heterogeneous and due to a mutation at codon 248, which results in the substitution of arginine to cysteine, in about 55% of the cases. This assay assesses the sites of disease-associated mutations in FGFR3 by PCR-based Sanger sequencing.

CPT Code

  • 81404