Glutaric Acidemia Type I: Atypical Presentation With Visual Disturbances After Mild Head Trauma in a Pediatric Patient

Glutaric Acidemia Type I (GA1) is a rare autosomal recessive metabolic disorder caused by mutations in the GCDH gene, which encodes glutaryl-CoA dehydrogenase, an enzyme essential for the breakdown of lysine and tryptophan. Enzyme deficiency leads to the accumulation of neurotoxic metabolites, glutaric acid and 3-hydroxyglutaric acid, which can cause significant neurological impairment. While GA1 typically presents in early childhood, late-onset cases may occur beyond six years of age or even in adolescence, with some patients
remaining asymptomatic.
We describe the case of a previously healthy 9-year-old girl who presented to the Emergency Department with subjective visual disturbances for 10 days in her right eye following a mild head trauma during a judo practice. Neurological and Ophtalmological evaluation revealed homonymous hemianopsia on the right side and macrocephaly (head circumference >99th percentile, +3.3 Standart Deviations). While a history of suspected macrocephaly during infancy was noted, no detailed investigations were conducted at that time. After hospitalisation, on the next day visual distubances self-resolved and patient had no complaints. Brain MRI with spectroscopy was performed and revealed extensive white matter demyelination in the periventricular and subcortical regions of the frontal, parietal, and occipital lobes. Additional findings included polymicrogyria and arachnoid cysts in the temporal lobes bilaterally. Metabolic testing showed markedly elevated levels of glutaric acid, 3-hydroxyglutaric acid, 2-hydroxyglutaric acid, and alpha-ketoglutaric acid in urine. Genetic testing confirmed two pathogenic GCDH gene variants, establishing the diagnosis of GA1. The patient was recommended dietary restriction of lysine-containing products.
We presented an atypical case of Glutaric Acidemia Type I (GA1) in a pediatric patient who presented with transient visual disturbances following minor head trauma. This case highlights the diverse clinical manifestations of metabolic disorders. Accurate diagnosis is crucial, as it enables implementation of targeted dietary approach, possibly reducing the risk of further neurological deterioration.