Refsum Disease

INTRODUCTION:
  • Refsum disease, also known as classic or adult Refsum disease, heredopathia atactica polyneuritiformis, phytanic acidoxidase deficiency and phytanic acid storage disease
  • It is an autosomal recessive neurological disease that results from the over-accumulation of phytanic acid in cells and tissues. 
  • Adolescent onset and is diagnosed by above average levels of phytanic acid.
ETIIOLOGY:
  • Refsum disease is a peroxisomal disorder caused by the impaired alpha-oxidation of branched chain fatty acids resulting in buildup of phytanic acid and its derivatives in the plasma and tissues.
  • This may be due to deficiencies of phytanoyl-CoA hydroxylase or peroxin-7 activity. In general, Refsum disease is caused by PHYH mutations.
CHARACTERISTICS:
  • Neurologic damage, cerebellar degeneration, and peripheral neuropathy. 
  • Onset is most commonly in childhood/adolescence with a progressive course, although periods of stagnation or remission occur. 
  • Symptoms also include ataxia, scaly skin (ichthyosis), difficulty hearing, and eye problems including retinitis pigmentosa, cataracts, and night blindness.
  • In 80% of patients diagnosed with Refsum disease, sensorineural hearing loss has been reported. 
TREATMENT:
  • Since phytanic acid is not produced in the human body, individuals with Refsum disease are commonly placed on a phytanic acid-restricted diet and avoid the consumption of fats from ruminant animals and certain fish, such as tuna, cod, and haddock.
  • Grass feeding animals and their milk are also avoided. 
  • CYP4isoform enzymes could help reduce the over-accumulation of phytanic acid in vivo
  • Plasmapheresis is another medical intervention used to treat patients. 
  
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