3 DLD (p.Y35X, p.G229C), 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.  Treatment consists of a strict, lifelong special diet to attempt to control the accumulation of amino acids in the blood. MSUD is inherited in an autosomal recessive manner and has a frequency of approximately 1/850,000 in the general population and approximately 30% of cases are of Ashkenazi Jewish heritage.