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What is Refsum Disease?
Refsum disease is an extremely rare and complex disorder that affects
many parts of the body. A form of the retinal degenerative disease
known as retinitis pigmentosa (RP) is a common feature of this disease.
What are the symptoms?
Individuals with Refsum disease are unable to metabolize phytanic acid.
As a result, high levels of phytanic acid accumulate in the blood and
tissue. It is thought that disorders associated with this disease
result from harmful levels of phytanic acid.
Phytanic acid is found in meat, fish, and dairy products. The body also
converts phytol, a substance found in green leafy vegetables, to
Refsum disease is usually diagnosed during childhood or young adulthood
when vision problems due to RP become apparent. Progressive vision loss
from RP begins when harmful levels of phytanic acid collect beneath the
retina. The retina is essential to vision as it converts light into
electrical impulses and then transfers these impulses to the brain via
the optic nerve.
The first symptom of RP is night blindness followed by a gradual loss
of peripheral (side) vision.
Night blindness makes vision difficult in dark or dimly lit places.
The loss of peripheral vision is often referred to as tunnel vision. RP
tends to progress slowly in patients with Refsum disease.
Cataracts, which are common to RP, are also seen in individuals with
Cataracts hamper vision by clouding the lens of the eye making it
difficult for light to reach the retina. In most cases, however,
cataracts can be surgically removed. The extent of vision loss with
Refsum disease varies greatly depending on the levels of phytanic acid
and the presence of cataracts.
In addition to vision-related disorders, individuals with Refsum
disease experience other sensory complications.
Loss of smell (anosmia) usually occurs in early childhood but may go
undiagnosed until other more pronounced symptoms become apparent.
Gradual or sudden hearing loss can occur in adulthood, usually after
the third decade.
Cardiac (heart) abnormalities, peripheral neuropathy (nerve disorder
causing loss of sensation), ataxia (balance disorder), paresthesia
(unusual burning or prickling sensation of skin), ichthyosis (dry,
scaly skin), anorexia (loss of appetite), and skeletal bone
abnormalities are also common.
Is it an inherited disease?
Refsum disease is genetically passed through families by the autosomal
recessive pattern of inheritance. In this type of inheritance, both
parents, called carriers, have one gene for the disease paired with one
normal gene. Each of their children then has a 25 percent chance (or 1
chance in 4) of inheriting the two Refsum disease genes (one from each
parent) needed to cause the disorder.
Carriers are unaffected because they have only one copy of the gene. At
this time, it is difficult to determine who is a carrier for Refsum
disease until after the birth of an affected child. However, slightly
elevated levels of phytanic acid have been detected in some people
thought to be carriers for Refsum disease.
What treatment is available?
A diet low in foods containing phytanic acid and phytol may arrest the
progression of RP and lessen the severity of other complications
associated with Refsum disease. To help control these complications, it
is important that patients maintain their body weight. Weight loss
releases phytanic acid stored in body tissue and increases symptoms
associated with the disease. Patients should be supervised by a
physician to monitor blood levels of phytanic acid and adjust dietary
regimens. A physician can also prescribe medications to enhance
Individuals with Refsum disease should have their heart monitored
regularly by a physician. A neurologist can evaluate and monitor
individuals with peripheral neuropathy and ataxia.
Lotions may help control skin problems. As vision declines, individuals
with Refsum disease may benefit from the use of low-vision aids,
including electronic, computer-based, and optical aids. Orientation and
mobility training, adaptive skills, job placement, and income
assistance are available through community resources. Ongoing
scientific research is directed at identifying the gene that causes
Refsum disease to develop improved treatments.
Researchers have identified genetic variations that cause Refsum
disease. These genetic findings are giving scientists targets for
Are there any other related diseases or syndromes?
Refsum disease can be confused with other similar disorders.
Bassen-Kornzweig disease, also known as abetalipoproteinemia, is
characterized by retinal degeneration, neuromuscular disability and
dietary fat intolerance. Kearns-Sayre syndrome involves retinal
degeneration, ptosis (drooping of upper eyelid), deafness, muscular
dystrophy, and cardiac abnormalities. Expert medical consultation can
distinguish between these disorders.
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