Glutaric aciduria type 1 presenting with Parkinsonism with presynaptic dopaminergic dysfunction in an adult female: a case report

Glutaric aciduria type 1 (GA1) is an autosomal recessive neurometabolic disorder caused by pathogenic variants in the GCDH gene, typically presenting in infancy with dystonia following encephalopathic crisis. Late- and adult-onset forms are rare and may manifest with nonspecific neurological features. We describe a 43-year-old woman with levodopa-responsive parkinsonism and presynaptic dopaminergic dysfunction. Genetic analysis revealed compound heterozygous GCDH variants, consistent with GA1. One of the reported variants (c.1178G > A, p. Gly393Glu) is extremely rare and has never been associated with adult-diagnosed GA1 with atypical features. Furthermore, this is the first report of GA1 patient presenting with parkinsonism in whom we demonstrated presynaptic dopaminergic dysfunction, along with a favorable response to levodopa.