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Genetic Testing Lab

Test Catalog Molecular Genetics Laboratory Maple Syrup Urine Disease

Maple Syrup Urine Disease

Test Description:
Maple Syrup Urine Disease (MSUD) is an autosomal recessive metabolic disorder that is caused by deficiency in the activity of an enzyme complex referred to as branched-chained-a-ketoacid acid dehydrogenase (BCKD) complex. The most severe presentation of MSUD, known as “classic” MSUD, accounts for 80% of cases and can result in neonatal onset with encephalopathy and coma. Although metabolic management of the disease is possible and newborn screening for MSUD is available in many states, the outcome is unpredictable and a significant portion of affected individuals are mentally impaired or experience neurological complications. MSUD is a panethnic disorder, but it has increased incidence in the Ashkenazi Jewish population where the carrier frequency of approximately 1 in 97 in this population. Testing for the three BCKDHB mutations, p.R183P, p.G278S, p.E372* (E422*), should identify >95% of MSUD Type IB carriers in the Ashkenazi Jewish population. Carrier screening for MSUD may be considered for individuals of Eastern European (Ashkenazi) Jewish ancestry before or during pregnancy.

Full gene sequencing is available for reproductive partners of know mutation carriers. Prenatal diagnosis is also available. Prior to ordering prenatal testing, please contact our laboratory at 212-241-7518 to discuss.

References:
1. Chuang DT and Shih VE (2000) Disorders of branched chain amino acid and keto metabolism. In Scriver CR, Beaudet et al., (eds) The metabolic and molecular basis of inherited disease, 8th ed. McGraw Hill, New York, pp 1971-2006.
2. Edelmann L et al., (2001) Maple syrup urine disease: identification and carrier-frequency determination of a novel founder mutation in the ashkenazi jewish population. Am. J. Hum. Genet. 69:863-868.
3. Levin ML et al., (1993) Cerebral edema in maple syrup urine disease. J. Pediatr. 119:46-50.
4. Scott, S.A., Edelmann, L., Liu, L., Luo, M., Desnick, R.J. and Kornreich, R. Experience with carrier screening and prenatal diagnosis for sixteen Ashkenazi Jewish Genetic Diseases. Hum. Mutat. 31:1-11, 2010.

Specimen Requirements:

Post-natal: Two 5-10 mL tubes of anticoagulated blood in EDTA (lavender top) or two 5-10 mL tubes of anticoagulated blood in ACD (yellow top).

Prenatal: 

  • Chorionic Villi: 5-10 mg in conical tube with sterile saline OR transport media
  • Amniotic Fluid: 10 ml in conical tube
  • Cultured Cells: two confluent T-25 flasks

Additionally, please send:

  • 5-10 ml maternal blood in EDTA (lavender top) required to perform MCC studies on all prenatal samples and in case maternal confirmation studies are necessary
  • 5-10 ml paternal blood in EDTA (lavender top) in case paternal confirmation studies are necessary

Shipping: Send at room temperature.

Turnaround Time: 10-14 days

CPT Code: 81205

Consent and Requisition Forms: Carrier Screening Requisition and Consent [PDF]

Additional Information: Expanded Ashkenazi Jewish Carrier Screening Brochure [PDF]

Related Tests: Ashkenazi Jewish Carrier Test Panel

Prior to ordering prenatal testing, please contact our laboratory at 212-241-7518 to discuss.