Crouzon and Pfeiffer Syndrome – Craniodysmorphology Testing

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CROUZON AND PFEIFFER SYNDROME – CRANIODYSMORPHOLOGY TESTING
 
 
Gene Symbol: FGFR2  
       
Chromosomal Locus: 10q26
 
Protein:  Fibroblast growth factor receptor 2 
 
Pseudonyms: exon 7/IIIa & exon 10/ IIIc, Craniosynostosis
 
TURNAROUND TIME:     15 days
Testing offered as a Craniodysmorphology screen or panel
 
Screen: 83890 x 1, 83892 x 6, 83894 x 3, 83898 x6, 83904 x 6, 83912 x 3
 
Panel:  83890 x 1, 83892 x 6, 83894 x 4, 83898 x 7, 83904 x 12, 83912 x 4
 
TESTING METHODOLOGY: PCRamplification and DNA sequencing of exons 8 and 10 (7/IIIa and 9/IIIc) of the FGFR2 gene. Ordered as Craniodysmorphology Screen or Craniodysmorphology Panel.  
 
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: Incidence: 1 in 2,000 for Craniosynostosis; 1 in 60,000 for Crouzon and Pfeiffer syndromes combined.
 
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, causingunicoronal or bicoronal craniosynostosis or cloverleaf skull. Also 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. The majority of the mutations are located within exons 8 and 10 of the FGFR2 gene.
 
 
 
Clinical Sensitivity: 80%
 
Analytical Sensitivity: 99%
 
Test Limitations: Deletions of the entire gene or mutations outside the tested regions of the genes 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.
  • To discriminate between syndromes with overlapping clinical symptoms.
  • Prenatal diagnosis for individuals at risk or with ultrasound findings.
ADDITIONAL RESOURCES:
Genetics Home Reference: www.ghr.nlm.nih.gov/gene/FGFR2