Refsum disease: Overview

Refsum disease is an inherited condition that causes vision loss, absence of the sense of smell (anosmia), and a variety of other signs and symptoms.

The vision loss associated with Refsum disease is caused by an eye disorder called retinitis pigmentosa. This disorder affects the retina, the light-sensitive layer at the back of the eye. Vision loss occurs as the light-sensing cells of the retina gradually deteriorate. The first sign of retinitis pigmentosa is usually a loss of night vision, which often becomes apparent in childhood. Over a period of years, the disease disrupts side (peripheral) vision and may eventually lead to blindness.

Vision loss and anosmia are seen in almost everyone with Refsum disease, but other signs and symptoms vary. About one-third of affected individuals are born with bone abnormalities of the hands and feet. Features that appear later in life can include progressive muscle weakness and wasting; poor balance and coordination (ataxia); hearing loss; and dry, scaly skin (ichthyosis). Additionally, some people with Refsum disease develop an abnormal heart rhythm (arrhythmia) and related heart problems that can be life-threatening.

Source: GHR (NLM/NIH)1

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Back to: « Refsum disease

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Refsum disease is a rare disorder of lipid metabolism that is inherited as a recessive trait. Symptoms may include a degenerative nerve disease (peripheral neuropathy), failure of muscle coordination (ataxia), retinitis pigmentosa (a progressive vision disorder), and bone and skin changes. Refsum disease is characterized by an accumulation of phytanic acid in the plasma and tissues. is a derivative of phytol, a component of chlorophyll.

In 1997 the gene for Refsum disease was identified and mapped to chromosome 10. The protein product of the gene, PAHX, is an enzyme that is required for the metabolism of phytanic acid. Refsum disease patients have impaired PAHX - phytanic acid hydrolase. It is thought that Refsum disease is a peroxisomal disorder, since human PAHX contains PTS2 localization sequences, which target it to the peroxisome.

Our bodies can not synthesize phytanic acid: we have to obtain all of it from our food. Therefore, prolonged treatment with a diet deficient in phytanic acid can be beneficial.

Source: NCBI, Genes and Disease (NCBI/NIH)2

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Summary

Refsum disease is an inherited condition that causes vision loss, loss of smell (anosmia), and a variety of other signs and symptoms. The vision loss associated with Refsum disease is caused by an eye disorder called retinitis pigmentosa. Other features can include bone abnormalities of the hands and feet; progressive muscle weakness and wasting; poor balance and coordination (ataxia); hearing loss; arrhythmias and heart abnormalities; and dry, scaly skin (ichthyosis). Refsum disease can result from mutations in the PHYH gene or the PEX7 gene and is inherited in an autosomal recessive pattern.[1] Last updated: 11/9/2011

Source: GARD (NIH)3

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Refsum Disease: A rare autosomal recessive disorder characterized by abnormalities in the breakdown of phytanic acid and impaired growth of myelin sheaths. Signs and symptoms include neurologic damage, cerebellar degeneration, and neuropathy.4

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Refsum Disease: An autosomal recessive familial disorder that usually presents in childhood with Polyneuropathy; Sensorineural Hearing Loss; Ichthyosis; Ataxia; Retinitis Pigmentosa; and Cardiomyopathies. (From Joynt, Clinical Neurology, 1991, Ch37, p58-9; Rev Med Interne 1996;17(5):391-8) This condition can be caused by mutation in the genes encoding peroxisomal phytanoyl-CoA hydroxylase or proteins associated peroxisomal membrane, leading to impaired catabolism of Phytanic Acid in Peroxisomes.5

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Refsum disease (RD) is a very rare, clinically variable, multisystemic metabolic disease, characterized by anosmia,early-onset retinitis pigmentosa (see this term) and possible neurological manifestations, including neuropathy, and cerebellar ataxia, deafness, ichthyosis, skeletal abnormalities, and cardiac arrhythmia. It is characterized biochemically by accumulation of phytanic acid in plasma and tissues.6

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References

  1. Source: GHR (NLM/NIH): ghr.nlm.nih.gov/ condition/ refsum-disease
  2. Source: NCBI, Genes and Disease (NCBI/NIH): ncbi.nlm.nih.gov/ books/ NBK22208/ 
  3. Source: GARD (NIH): rarediseases.info.nih.gov/ diseases/ 5691/ refsum-disease
  4. Source: NCI Thesaurus
  5. Source: MeSH (U.S. National Library of Medicine)
  6. Source: Monarch Initiative

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Note: This site is for informational purposes only and is not medical advice. See your doctor or other qualified medical professional for all your medical needs.