Isolated Non-Progressive Hemidystonia in a Patient Homozygous for H63D Variant of Hereditary Hemochromatosis: A Case Report and Systematic Literature Review of Movement Disorders in Hereditary Hemochromatosis

Abstract

Background: Hereditary hemochromatosis (HH) is a genetic disorder of iron metabolism, characterized by progressive iron accumulation. Neurological involvement, which can manifest with various symptoms, including movement disorders, is uncommon. Methods: We describe a case of a 50-year-old male patient homozygous for the H63D variant of the HFE gene (encoding the human homeostatic iron regulator protein), who also carried the c.340+4T>C polymorphism in the same gene and has been affected since the age of 13 years by hemidystonia involving primarily his right upper extremity. His brain MRI, obtained approximately 35 years after initial symptoms, revealed iron deposition predominantly in the contralateral pallidum. The patient has shown no progression of his neurologic syndrome and no systemic manifestations over the 35 years of follow-up. Moreover, we conducted a comprehensive literature search in Pubmed and Web of Science in English of all previously reported cases of movement disorders due to HH. Results: We found 19 studies including 69 patients with movement disorders. Movement disorders associated with HH were, in most cases, hypokinetic and less commonly hyperkinetic. The most common movement disorders were tremor, parkinsonism, ataxia, and less frequent dystonia, chorea, and myoclonus. Movement disorders could either precede the diagnosis of HH, or they could occur with a variable latency ranging from a few months up to 12 years after disease onset. Iron deposition on brain MRI in the basal ganglia or cerebellum was found in few of those cases. Conclusions: The association between hemochromatosis and movement disorders is rare. Blood analysis, including serum iron, ferritin, and transferrin saturation levels, should be investigated in patients with movement disorders of unknown etiology or with iron deposition on neuroimaging. A better understanding of genotype-phenotype correlations would facilitate the early diagnosis of HH.