Early-Onset Sensorimotor Axonal Neuropathy as Sole Manifestation of HADHA -Related Disorder/ Mitochondrial Trifunctional Protein Defect

Pathogenic variants in the HADHA and HADHB genes are associated with impairment of mitochondrial trifunctional protein. Mitochondrial trifunctional protein deficiency is a disorder of long-chain fatty acid oxidation with different clinical presentations: the neonatal-onset form expressing with severe cardiac phenotype, the infantile-onset form with intermediate hepatic phenotype with metabolic crises, and the late-onset form with mild neuromyopathic phenotype. Long-term complications in patients with the intermediate and late-onset phenotypes include peripheral neuropathy and retinopathy. We report a patient harboring 2 compound heterozygous variants in the HADHA gene (p.Tyr724* and p.Gly319Ser) and presenting with an early-onset, progressive sensorimotor axonal polyneuropathy, without any other systemic manifestations typical of mitochondrial trifunctional protein deficiency. We also provide a literature review of HADHA mutated patients presenting with early-onset isolated neuropathy phenotype.