Widening the phenotypic spectrum - Non epileptic presentation of folate transporter deficiency

Abstract

Introduction: Folate is essential for production of DNA, neurotransmitters and myelin and regulation of genetic activity. A specific transporter protein is required to transport folate from blood to CSF. Various inherited brain-specific folate transport defects have been recognized due to mutation in Folate Receptor alpha (FOLR1). FOLR1 mutation is one of the vitamin responsive encephalopathies and is inherited as an autosomal recessive condition. It has a wide spectrum of phenotype, commonly presenting as epileptic encephalopathy. Less frequently the condition may manifest with subtle hypotonia, movement disorder as tremors, ataxia or intellectual disability and autistic spectrum disorder. We present a case of folate transporter deficiency with non-epileptic manifestations, presenting with tremors, speech delay and stable white matter changes in MRI brain.

Objective: We present a case of Folate transporter defect with Non-epileptic presentation.

Conclusion: Folate transporter deficiency has a wide range of presenting symptoms. Presentation with slowly progressive atypical symptoms, stable white matter changes in brain MRI that does not fit a specific diagnosis, should raise a high suspicion of FOLR1 mutation, even in absence of seizures. Since folate transporter deficiency is a treatable neurodegenerative disorder, early diagnosis and supplementation with folinic acid is vital.

Keywords: Folate transporter defect; Folinic acid; Non-epileptic; Seizures; Tremors; White matter hyperintensity.