From the Research
Refsum disease typically presents in late childhood or early adolescence, with most cases being diagnosed between the ages of 10 and 20 years, although the age of presentation can vary widely, as evidenced by a study showing a mean age at diagnosis of 35.5 years 1. The disease often begins with night blindness (nyctalopia) due to retinitis pigmentosa, followed by progressive visual field constriction and eventual blindness. Other early manifestations include anosmia (loss of smell), peripheral neuropathy causing weakness and sensory disturbances, and cerebellar ataxia affecting coordination and balance. Some key points to consider include:
- The variability in presentation age relates to the accumulation of phytanic acid, which depends on dietary intake of phytol-containing foods and individual metabolic differences in the defective alpha-oxidation pathway 2.
- Some patients may have milder enzyme deficiencies, allowing them to process small amounts of phytanic acid and delaying symptom onset 3.
- Early diagnosis is crucial as dietary restriction of phytanic acid can slow disease progression, as demonstrated by improved electroretinographic responses following dietary intervention in a patient with Refsum disease 4.
- A retrospective survey analysis found that most participants exercise at least once per week and have a low-phytanic-acid diet, highlighting the importance of lifestyle modifications in managing the disease 1.
- A case report of a patient with late-onset Refsum disease presenting with leukodystrophy suggests that the disease can manifest in unusual ways, even in adulthood 5.