Low Arginine in Gyrate Atrophy

Dietician Haritha Shyam, Diet, Food, Nutrition
It's fascinating to know that nutrition plays a role in eye disorders, and a dietitian can assist in either preventing or mitigating the progression of the disease. In this case, we'll explore how a low arginine diet can benefit individuals with Gyrate Atrophy.

What is Gyrate Atrophy?

  • Gyrate Atrophy is a rare inherited disease of the eye's retina and choroid, characterized by nearsightedness, cataracts, and progressive loss of vision.
  • Genetic defects impair essential metabolic pathways and cause the toxic accumulation of specific metabolites, which can damage the retina and choroid plexus.
  • Extreme nearsightedness is common
  • The retina deteriorates from the periphery to the center causing a progressive narrowing of the field of vision (tunnel vision).
Progression of the disease

  • During childhood, they begin experiencing near-sightedness (myopia), difficulty seeing in low light (night blindness), and loss of side (peripheral) vision
  • As time progress, their field of vision continues to narrow, (tunnel vision)
  • Many people with Gyrate Atrophy also suffer from clouding of the lens of their eyes (cataracts). These progressive vision changes lead to blindness by about the age of 50 - as there is some amount of vision, the condition is either undiagnosed or underdiagnosed. The patient does not get any treatment as there is no medical intervention.
Deficiency of OKT

  • The basic biochemical defect is a deficiency of themitochondrial enzyme ornithine ketoacid transaminase(OKT), which converts ornithine to glutamic-y-semialdehyde.
  • Resulting in the accumulation of ornithine and progressivechorioretinal degeneration of unknown Pathogenesis.
Symptoms of visual equity

  • Most people with this condition show no symptoms at allapart from vision loss, but some people show additionalfeatures of the disorder.
  • Occasionally, newborns with gyrate atrophy develop excessammonia in the blood (hyperammonemia), which may lead topoor feeding, vomiting, seizures, or coma.
  • In a few cases, mild to moderate intellectual disability is alsoassociated with this condition. Gyrate Atrophy may also causedisturbances in the nerves connecting your brain and spinalcord to your muscles and sensory cells (peripheral nervoussystem).
  • The slowly progressive irreversible loss of vision from retinaldegeneration often leads to complete blindness, usually bythe fourth or fifth decade of life.

  • Screening for carrier status and diagnosis of a geneticcondition is only possible through genetic testing. If similarsymptoms are noticed in another sibling, early screeningshould be done for the younger child. 
  • Through DNA testing the exact underlying genetic defect canbe identified.
Role of Ornithine and Arginine

  • The most common method of reducing the buildupof ornithine is by reducing the intake of its source,arginine, through a low-arginine diet.

There is no pharmaceutical treatment available to haltthe progression of the disorder, making dietaryrestrictions the only form of treatment. Earlyintervention through dietary restrictions can slow theprogression of the disease and potentially preservesome vision.

  • It has been demonstrated that a diet that is low inprotein and specifically restricts the intake ofarginine can slow down the decline in function asdemonstrated by changes in the visual field. 
  • Ornithine is not present in proteins as an amino acidand is instead generated from Arginine in humans.This is why we cannot identify foods that are high inOrnithine, instead, we need to identify foods thatcontain high levels of Arginine. 
  • It has been observed that some patients experiencea decrease in their Ornithine levels after taking largedoses of Vitamin B6. Vitamin B6 serves as theprecursor to pyridoxal phosphate. 
  • Increasing Lysine intake is also suggested as apotential remedy, however, it is not a guaranteedtreatment. Lysine supplementation may berecommended for certain individuals.
Therefore, the only form of therapy is a low Argininediet.

Food rich in arginine

  • Nuts -walnut, peanut, pistachio, ground nut, cashewnut, raisins 
  • Seeds - sunflower seeds 
  • Gelatin 
  • Chocolate, cheese, coconut, oats 
  • Whole wheat and its products 
  • Soybeans 
  • Wheat germ