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Is there such a thing as cysteine deficiency in humans or other mammals?

What effects would such a deficiency have?

As I understand it, most cysteine for humans comes from dietary sources, though it can be biosynthesized in humans.

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Cysteine deficiencies are possible, and one cause is the genetic disorder homocystinuria. Cysteine can be produced from methionine through a homocysteine intermediate, and defective genes for the enzymes involved can prevent proper cysteine production and cause a buildup of homocysteine. Patients have to eat a very carefully controlled diet with very low amounts of protein. This prevents homocysteine buildup by avoiding methionine exposure, but also requires that the patient take vitamin B6 and B12 supplements and betaine. They might need to take cysteine supplements as well. The symptoms affect many organ systems, including the brain, nerves, and blood vessels, with about 25% of patients dying due to blood clots by age 30.

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