Maple Syrup Urine Disease Type 3 (part of Ashkenazi Jewish FlexPanel)
Maple Syrup Urine Disease, MSUD, is characterized by the presence of sweet-smelling urine, with an odor similar to that of maple syrup. Infants with this disease seem healthy at birth but if left untreated suffer severe mental and physical retardation, feeding problems, and eventually death due to the accumulation of branched-chain amino acids.
PrintMaple Syrup Urine Disease, MSUD, is characterized by the presence of sweet-smelling urine, with an odor similar to that of maple syrup. Infants with this disease seem healthy at birth but if left untreated suffer severe mental and physical retardation, feeding problems, and eventually death due to the accumulation of branched-chain amino acids.
Clinically, newborn infants with MSUD Type 3 are similar to patients with intermediate MSUD, but severe lactic acidosis is also present. The infants develop a persistent lactic acidosis between 8 weeks and 6 months of age followed by progressive neurologic deterioration with hypotonia, developmental delay, and movement disorder. The patients have a combined deficiency of BCKD, pyruvate, and alpha-ketoglutarate dehydrogenase complexes, leading to the more complex phenotype than intermediate MSUD. It is an autosomal recessive disorder caused by mutations in the DLD gene. It occurs more frequently in the Ashkenazi Jewish population, where the carrier rate is 1 in 110. Ashkenazi Jewish individuals with a negative family history who test negative for the p.Y35X and p.G229C mutations in DLD have a revised carrier risk of 1 in 2,180.
Analysis of the p.Y35X and p.G229C mutations in DLD by pyrosequencing. This test can be ordered as part of the Ashkenazi Jewish FlexPanel
The mutation detection rate in the Ashkenazi Jewish population is 95%.