Isovaleric acidemia ranges in severity from asymptomatic to mild or life-threatening symptoms depending on the mutation and factors predisposing acute attacks. Two major clinical scenarios are often described, an acute form and a chronic intermittent form, but in reality the disease is best thought of as a continuous spectrum from asymptomatic to life threatening. A characteristic ‘sweaty feet’ odor is often present in patient sweat or cerumen due to a buildup of isovaleric acid. Patients may develop aversion early to protein-rich foods.
Acute, early symptoms present soon after birth with increasing lethargy, poor feeding and vomiting, progressing to coma. After the newborn period chronic intermittent symptoms are usual. Patients can have slowed growth rates (failure to thrive), developmental delay, intellectual disability or symptoms affecting the nervous system such as seizures and spasticity, most commonly related to early acute damage. Patients can also experience acute attacks similar to the newborn period, typically triggered by other illnesses such as infections. Patients can exhibit a chronic picture even if a newborn acute attack has not occurred. Isovaleric acidemia can be identified by newborn screening.
IVD