Refsum disease (hereditary motor and sensory neuropathy type IV (HMSN IV) or Heredopathia Atactica Polyneuritiformis) It is due to phytanic oxidase deficiency.
Incidence
AR disease. Rare in childhood but some manifestations may be congenital, like bone deformities. Caused by abnormal accumulation of phytanic acid (C16 BCFA)
Clinical Characteristics
Symptoms start after age 4-7 yrs but may be recognized later. Slow progression. Variable clinical picture. Intermittent peripheral neuropathy. Ataxia often marked. Atypical retinitis pigmentosa is present with night blindness as first symptom. Absent ERG. Absent DTR CSF protein elevated often > 100 mg% with no cells. High phytanic acid levels in plasma.
Precipitants
no
Provocation Tests
no
Diagnostic Procedures
Determine phytanic acid in plasma, which is elevated to 300-1600 umol/L (nl=<10 umol/L) (abn 10-50 mg% vs. nl <0.3 mg%).