Table 1 Summary of the five main types of MSUD
Type | Age of onset | Affected gene | Clinical features |
|---|---|---|---|
Classic | Neonatal | BCKDHA BCKDHB DBT | Maple syrup odor of cerumen Poor feeding Irritability, lethargy Opisthotonos Focal dystonia “Fencing,” “bicycling” Obtundation, coma Central respiratory failure |
Intermediate | Variable | BCKDHA BCKDHB DBT | Maple syrup odor of cerumen Poor growth Poor feeding Irritability Developmental delays Encephalopathy during illness |
Intermittent | Variable | BCKDHA BCKDHB DBT | Normal early growth & development Episodic decompensations that can be severe |
Thiamine responsive | Variable | DBT | Like the intermediate type |
E3 deficient | Variable | DLD | Early-onset neurologic phenotype: Hypotonia Developmental delay Emesis Hepatomegaly Lethargy Seizures Spasticity Leigh syndrome Failure to thrive. Hepatic phenotype: Nausea Emesis Hepatomegaly Hepatic encephalopathy |