Background:
Prader-Willi (PWS) syndrome is characterized by severe hypotonia and feeding difficulties in early infancy, followed in late-infancy/early childhood by excessive eating and obesity. Developmental delay is common as are hypogonadism and short stature. Most cases (99%) are caused by absence of a paternal contribution to the imprinted region on chromosome 15q11-q13; approximately 70% of these are due to a large ~5-7 Mb deletion detectable by high resolution chromosome analysis and/or FISH. The remaining cases include smaller mutations and maternal uniparental disomy – tests for both of these are available in the KDL Molecular Genetics Laboratory.
Methodology:
Slides are prepared per standard protocols. Ten metaphase cells and 50 interphase cells are scored under fluorescence microscopy.
Specimen Requirements:
Blood:
- Adult - 3-5 mL drawn into a GREEN top sodium heparin vacutainer tube or into a pre-heparinized plastic syringe (use 0.2 cc sodium heparin, 1000 unit/mL). Do NOT use lithium heparin.
- Child - 1-2 mL, as above.
- Infant - 1-2 mL, as above.
- Keep at room temperature and transport to laboratory as soon as possible.
- Contact Client Services at (855) 535-1522 for supplies and instructions.
A REQUISITION FORM MUST ACCOMPANY ALL SAMPLES. Please include detailed clinical information, including ethnicity, clinical history, and family history.
Test Performed (Days):
Mon-Sat
Turn Around Time:
3-7 days
Shipment Sensitivity Requirements:
Ship via overnight express, using the FedEx priority overnight label provided. Contact Client Services at (855) 535-1522 for shipping kits and instructions.
References:
Additional Info: