Maple Syrup Urine Disease (MSUD). Classical type. Branched-chain ketoacid dehydrogenase complex deficiency (3 units).
Incidence
1:220.000 in USA. Autos. recessive. Very common disease in the Middle East, as high as 1:2000
Clinical Characteristics
Devastating metabolic disease of newborns 3-10 days of life.Mild hypoglycemia and ketoacidosis.Coma, lethargy and seizures. Progressive and severe CNS disease with long tract signs and gray matter disease. Burned sugar odor in urine and ear wax. Alternating hypotonia with hypertonia is very characteristic (alternating opistotonus). No other metabolic disease cause so severe brain edema in the neonatal period as MSUD. Acidosis if present is usually very mild clinically.
Precipitants
Infections, fasting
Provocation Tests
no
Diagnostic Procedures
2,4,dinitrophenylhydrazine urine test strongly positive, ferric chloride occasionally navy blue. EB(W,F)