Most patients with glutaric acidemia are born with macrocephaly
and develop normally until they suddenly develop hypotonia and dystonia during
or after an intercurrent infection; this usually occurs during the
first 2 to 3 years of life. CT-MRI scans show frontal and cortical
atrophy from birth and, after the onset of dystonia, degeneration
of the caudate nucleus and putamen. Some patients gradually develop
signs of striatal degeneration during the first years of life, and others,
probably less than 5% of patients, remain asymptomatic.
Metabolic acidosis, the usual indication for organic acid screening,
is rare.