Diagnostic testing for Freeman-Sheldon syndrome.
- 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: "Whistler appearance" due to facial muscle contractures, joint contractures of hands and feet, facial dysmorphism, strabismus, dental crowding, restricted cervical flexion, scoliosis, hearing loss, cryptorchidism and inguinal hernia.
Prevalence: Uncertain; approximately 100 cases have been reported to date.
Inheritance: Autosomal dominant.
Cause: Pathogenic MYH3 gene mutations.
Clinical Sensitivity: Approximately 70 percent.
Methodology: Bidirectional sequencing of MYH3 exon 17 which includes the two most common mutations, R672C and R672H.
Analytical Sensitivity and Specificity: 99 percent.
Limitations:Diagnostic errors can occur due to rare sequence variations. Mutations outside exon 17 will not be detected.
Counseling and informed consent are recommended for genetic testing. Consent forms are available online.
|Component Test Code*||Component Chart Name||LOINC|
|2002663||FSS SEQ Specimen|
|2002664||Freeman-Sheldon Syndrome Interpretation|
- Whistling Face Syndrome