Icahn School of Medicine at Mount Sinai
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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, however it has increased incidence in the Ashkenazi Jewish population with a carrier frequency of approximately 1 in 97 in this population. Testing for the three BCKDHB mutations, p.R183P, p.G278S, p.E372X (E422X), 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/during pregnancy.

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:
Two 5-10 ml tubes of anticoagulated blood. The preferred anticoagulant is EDTA (lavendar top tubes), ACD (yellow top) tubes are also accepted.

Shipping: Send at room temperature.

Turnaround Time: 10-14 days

CPT Codes: 83891, 83892x2, 83900, 83912, 83914x2

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

Additional Information: Jewish Genetic 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.