Skeletal Dysplasias: FGFR3 Hotspot Panel with Reflex to Full Gene Sequencing


Related Gene(s): FGFR3

The phenotypic variation of skeletal dysplasias points to a complex etiology for this class of disorders. Some of the more common skeletal dysplasias, however, have been shown to be a consequence of a limited number of mutations in the fibroblast growth factor receptor 3 (FGFR3) gene. These skeletal dysplasias include achondroplasia (ACH), the most common genetic form of dwarfism, thanatophoric dysplasia (TD1 and TD2), the most common form of sporadic, lethal skeletal dysplasia, hypochondroplasia (HCH), a milder skeletal dysplasia which resembles achondroplasia, and nonsyndromic coronal craniosynostosis.

Performing postnatal genetic testing can be clinically useful for individuals that display characteristic features such as short stature or frontal bossing. However, this hotspot panel has greater utility prenatally for fetuses that present with certain ultrasound findings, such as shortened long bones, small ribcage, or cloverleaf skull, after a normal chromosome analysis. For more details on which mutations are included on the hotspot panel, please see the Skeletal Dysplasias: FGFR3 Hotspot Panel Information Sheet.

Testing can be ordered for just the hotspot panel of common mutations, or with the option of reflexing to full gene sequencing if the hotspot panel is negative. Additionally, targeted mutation analysis can be performed if a previous familial mutation has already been identified.

Prenatal diagnosis is also available. Prior to ordering prenatal testing, please contact our laboratory at 212-241-7518 to discuss.


Specimen Requirements

Prenatal

  • Chorionic villi: 4 mg in conical tube with sterile saline or transport media
  • Amniotic fluid: 15 mL in conical tube
  • Cultured cells: Two confluent T-25 flasks

  • Additionally, please send:
  • Maternal blood: 5-10 mL in EDTA tube (lavender top) required to perform MCC studies on all prenatal samples and in case maternal confirmation studies are necessary
  • Paternal blood: 5-10 mL in EDTA tube (lavender top) in case paternal confirmation studies are necessary

Postnatal

  • For adults
  • Blood: Two 5-10 mL tubes with EDTA (lavender top) or two 5-10 mL tubes with ACD (yellow top) from the patient.
  • Additionally, please send two 5-10 mL tubes with EDTA (lavender top) or two 5-10 mL tubes with ACD (yellow top) from both parents

  • For newborns or children
  • Blood: 2 mL in pediatric EDTA tube (lavender top) or 2 mL in pediatric ACD tube (yellow top) from patient
  • Additionally, please send 10-15 mL in EDTA tube (lavender top) or 10-15 mL in ACD tube (yellow top) from both parents

Ordering Information

Shipping

  • Ship at room temperature

Turnaround Time

  • Hotspot panel: 5-7 days
  • Optional reflexive full gene sequencing: 2-3 weeks (after completion of hotspot analysis)


Resources

General Test Requisition
Skeletal Dysplasias: FGFR3 Hotspot Panel Information Sheet