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FGFR2 - Gene Analysis Reflexed from Craniodysmorphology Screen

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Gene Symbol: FGFR2

Chromosomal Locus: 10q26.13
 
Protein:  Fibroblast growth factor receptor 2 
 
Pseudonyms: FGF receptor, protein tyrosine kinase, receptor-like, 14; TK14; Antley-Bixler syndrome, Apert syndrome, Beare-Stevenson, nonspecific Craniosynostosis, Crouzon syndrome, Jackson-Weiss syndrome, LADD syndrome, Pfeiffer syndrome, Saethre-Chotzen syndrome and Scaphocephaly with maxillary retrusion and mental retardation.
 
TURNAROUND TIME:     4 weeks
    
TESTING METHODOLOGY:PCRamplification and DNA sequencing of the entire coding region of the of the FGFR2 gene (FGFR2c isoform). Exons 8 and 10 are excluded since this test is a reflex test after a  Craniodysmorphology Screen; or Craniodysmorphology Panel. However, a modified form of the test can be ordered to include exons 8 & 10 FGFR2 Complete Gene Analysis, as well.
 
SPECIMEN REQUIREMENTS:
  • Collect:  Prefer two 5ml whole blood EDTA (lavender top) tube.  
  • Min. Collection: 0.7 ml whole blood EDTA.
  • Transport: Blood EDTA at Room Temp shipped regular next day air (No Saturday delivery; store specimen refrigerated and ship Monday). 
  • Stability: Ambient: up to 7 days; Refrigerated: 2 weeks. Frozen: unacceptable
  • Unacceptable Conditions: Serum. Frozen or severely hemolyzed blood. Clotted blood.         
  • Prenatal testing:  Direct: 5ml direct unspun amniotic fluid or 15mg CVS tissue with a backup flask growing. Culture: confluent T25 flask.  Maternal blood sample is required for maternal cell contamination studies.
A Molecular Genetics Laboratory Test Requisition must accompany the specimen. Contact the Molecular Laboratory at 918-502-1721 to obtain further information.
 
Note: Counseling and informed consent are recommended for genetic testing. A consent form is available as a resource but not required.
 
INTERPRETATIVE DATA:
Incidence: Craniosynostosis (1 / 2000), Crouzon syndrome (1/60,000) and Apert syndrome (1/10,000).
 
Inheritance:Spontaneous or inherited in an autosomal dominant manner. In the inherited form, the diseases are considered fully penetrant although variable expression is typical.
 
Disease Characteristics: Premature closure of the sutures between the bones of the skull, causing unicoronal or bicoronal craniosynostosis or cloverleaf skull. Also observed are distinctive facial features and variable abnormalities of the hands and feet.
 
Molecular Genetic Mechanism:  A variety of missense, nonsense and insertion/deletion mutations have been described.
 
 
Clinical Sensitivity: Up to 90% (including exons 8 & 10)
 
Analytical Sensitivity: 99%
 
Test Limitations: Deletions of the entire gene will not be detected.Rare diagnostic errors can occur due to primer or probe site mutations or rare polymorphisms.
 
INDICATIONS FOR USE:
  • To determine the genetic basis for craniodysmorphology in an affected individual.
  • The panel is designed to help discriminate between syndromes with overlapping clinical symptoms.
  • Prenatal diagnosis for Individuals at risk due to family history or ultrasound findings
ADDITIONAL RESOURCES:
OMIM Antley-Bixler - http://omim.org/entry/207410
OMIM Beare-Stevenson - http://omim.org/entry/123790
OMIM Jackson-Weiss - http://omim.org/entry/123150
OMIM LADD syndrome - http://omim.org/entry/149730
OMIM Scaphocephaly - http://omim.org/entry/609579
Genetics Home Reference:  www.ghr.nlm.nih.gov/gene/FGFR2