Refsum Disease
A rare metabolic disorder causing phytanic acid accumulation. Dietary restriction of phytanic acid is the most important treatment — and can halt disease progression.
PHYH enzyme deficiency means phytanic acid (from plant chlorophyll and dairy) cannot be broken down. It accumulates in tissues, causing progressive damage.
Retinitis pigmentosa (progressive vision loss), peripheral neuropathy (numbness/weakness in hands and feet), cerebellar ataxia (balance problems).
Cardiomyopathy and arrhythmias can occur. Regular cardiac monitoring (ECG, echocardiogram) is essential.
Mild to moderate scaling, typically appearing after neurological features. Responds well to dietary restriction — as phytanic acid levels fall, skin improves.
Phytanic Acid Dietary Guide
Phytanic acid is found in ruminant animal products (from chlorophyll processed by bacteria in their guts) and certain fish. It is NOT found in fruit, vegetables, grains, or white meat.
| Food Category | Phytanic Acid Content | Status | Guidance |
|---|---|---|---|
| Butter, cream, full-fat milk, cheese | High (600–8,000 mg/100g fat) | AVOID | Switch to plant-based alternatives or skimmed/fat-free dairy only |
| Lamb, beef, mutton (ruminants) | High | AVOID | Very lean cuts occasionally — remove all visible fat. Better to avoid. |
| Fatty fish (tuna, salmon, cod liver oil, herring) | High (phytol source) | AVOID | These contain phytol which converts to phytanic acid. Avoid completely. |
| Chicken, turkey, pork, rabbit | Very low / nil | ALLOWED | Non-ruminant meat — safe. Remove visible fat. |
| Fruit, vegetables, cereals, bread, pasta | Negligible | ALLOWED | Foundation of the diet. Unrestricted. |
| Eggs | Very low | ALLOWED | Generally safe. Occasional consumption. |
| Nuts and seeds | Low | ALLOWED | Most safe in normal quantities. Avoid phytol-rich supplements. |
| Plant-based milk (oat, soy, almond) | Negligible | PREFERRED | Excellent dairy substitute for Refsum. |
Monitoring and Treatment
| Monitoring | Frequency | Purpose |
|---|---|---|
| Serum phytanic acid level | Every 3–6 months | Primary treatment marker. Target <30 micromol/L. Ideally <10. |
| ECG and echocardiogram | Annually | Cardiac monitoring for cardiomyopathy and arrhythmias |
| Neurological assessment | Annually or as symptoms change | Peripheral neuropathy, cerebellar function, cognitive changes |
| Ophthalmology (retinal assessment) | Annually | Retinitis pigmentosa — visual field monitoring, dark adaptation |
| Audiology | Every 2 years | Sensorineural hearing loss can occur |
Plasmapheresis (Plasma Exchange)
In crisis situations — when phytanic acid is very elevated and causing rapid deterioration, or when calorie restriction risks mobilising stored fat — plasmapheresis (plasma exchange) can rapidly reduce phytanic acid levels:
- Blood is passed through a machine that removes plasma (and with it, phytanic acid)
- Used as a bridge while dietary restriction takes effect
- Also used pre-operatively or during illness when normal diet cannot be maintained
- Available at specialist metabolic centres — discuss with your neurologist
- NOT a substitute for long-term dietary restriction
Skin Management
Ichthyosis in Refsum is secondary to phytanic acid accumulation. As levels fall with diet, skin often improves significantly. In the meantime:
- Emollient (Diprobase, Epaderm) twice daily — same as for other ichthyosis types
- Urea 10–20% for scaling areas
- Warm baths with bath oil — scale softening
- Scale removal can be more vigorous than in severe types as Refsum ichthyosis is generally milder
Red Flags
- Sudden worsening of numbness, weakness, or balance — may indicate rapid phytanic acid rise
- Cardiac symptoms: palpitations, chest pain, shortness of breath
- During any acute illness or surgery — fasting can mobilise stored phytanic acid and cause crisis
- Rapid vision deterioration