What is Refsum Disease?
Refsum Disease is a rare genetic disease. The disease usually begins in late childhood or early adulthood, however, some people will not develop symptoms until their 40s or 50s.
What Are the Symptoms?
- Increasing night blindness due to degeneration of the retina
- Loss of the sense of smell
- Problems with balance and coordination
- Dry and scaly skin
- Heartbeat abnormalities
- Shortened bones in their fingers or toes, or a visibly shortened fourth toe.
How Do You Get Refsum Disease?
This disorder is inherited as a recessive trait. More than 90% of all cases result from mutations in the PHYH gene. The remaining cases are caused by mutations in a gene called PEX7. Due to this mutation, people with this disorder lack the enzyme in peroxisomes that break down phytanic acid, a type of fat found in certain foods. As a result, toxic levels of phytanic acid build up in the brain, blood, and other tissues.
How Is Refsum Disease Diagnosed?
This disorder is diagnosed by the presence of phytanic acid in blood or urine samples.
Is There a Treatment?
This disorder is treatable because phytanic acid is not produced by the body. It is only found in foods. The primary treatment is to restrict or avoid foods that contain phytanic acid, including dairy products, beef and lamb, and fatty fish such as tuna, cod, and haddock. Some individuals might also require plasmapheresis which controls the buildup of phytanic acid. Other treatment is symptomatic and supportive.
With treatment, muscle weakness, numbness, and dry and scaly skin generally disappear. Vision and hearing problems may persist and the sense of smell may not return. Untreated, Refsum Disease can lead to sudden death caused by heartbeat abnormalities.