Infantile Refsum Disease Associated with Hypobetalipoproteinemia

Infantile Refsum disease (IRD) is a rare peroxisome biogenesis disorder with wide range of clinical severity. Herein, we report a mild form of IRD who had been followed as a symptomatic hypobetalipoproteinemia resembling with abetalipoproteinemia. At 6 years of age, the patient was diagnosed as having hypobetalipoproteinemia with spinocerebellar degeneration, peripheral neuropathy, retinitis pigmentosa, mild mental retardation, and sensorineural hearing loss. Although low vitamin E levels normalized after oral supplementation, the patient's clinical symptoms worsened very slowly. At 30 years of age, elevated levels of very long chain fatty acids and phytanic acid and decreased plasmalogen levels were detected in the plasma. Genetic analysis revealed a homozygous mutation of Q67R in PEX10 . Although hypocholesterolemia is relatively common in IRD, it has been overlooked so far. Since there are many similarities between IRD and abetalipoproteinemia or symptomatic hypobetalipoproteinemia, care should be taken to differentiate symptomatic hypobetalipoproteinemia from IRD.