Systemic Primary Carnitine Deficiency Presenting With Substantia Nigra and Basal Ganglia Injury: A Case Report.
Level 4 - case-series / case-control
Single case report
PubMed 40191062 · doi:10.1002/jmd2.70014
What was done
This case report describes the clinical course, diagnostic workup, and management of a 1-year-9-month-old girl who presented with impaired consciousness, hypoketotic hypoglycemia, hyperammonemia, and myocardial hypertrophy following an unremarkable newborn screen. Management included high-calorie infusions, L-carnitine supplementation, extracorporeal membrane oxygenation (ECMO) for respiratory failure, genetic sequencing of the SLC22A5 gene, serial brain MRI, and targeted L-DOPA therapy for dystonia.
What was found
Genetic testing confirmed a homozygous SLC22A5 mutation alongside markedly low serum total and free carnitine levels. Day 7 brain MRI showed bilateral basal ganglia and substantia nigra lesions. Following severe dystonia and respiratory failure requiring ECMO, L-DOPA was started on day 62, which was followed by improvements in dystonia, motor function, and swallowing. By day 88, repeat MRI demonstrated resolution of the basal ganglia signal abnormalities, though cerebral atrophy remained.
Why it matters
It highlights substantia nigra and basal ganglia injury as a rare metabolic presentation of primary carnitine deficiency missed on newborn screening, and suggests L-DOPA may offer symptomatic relief for associated secondary dystonia.
Limits
Findings are limited to a single patient without controls. The relative therapeutic contribution of L-DOPA versus carnitine repletion and natural recovery cannot be definitively separated, and long-term neurodevelopmental outcomes beyond day 88 were not reported.
Cited by
- supports Individuals with inborn carnitine deficiency may need carnitine supplementation to achieve a low Glucose Ketone Index.