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Hartnup disease (also known as "pellagra-like dermatosis" [1] and "Hartnup disorder" [2]) is an autosomal recessive [3] metabolic disorder affecting the absorption of nonpolar amino acids (particularly tryptophan that can be, in turn, converted into serotonin, melatonin, and niacin).
A man with pellagra, which is caused by a chronic lack of vitamin B 3 in the diet. Severe deficiency of niacin in the diet causes the disease pellagra, characterized by diarrhea, sun-sensitive dermatitis involving hyperpigmentation and thickening of the skin (see image), inflammation of the mouth and tongue, delirium, dementia, and if left untreated, death. [7]
Carcinoid syndrome thus may produce niacin deficiency and clinical manifestations of pellagra. Anti-tuberculosis medication tends to bind to vitamin B 6 and reduce niacin synthesis, since B 6 (pyridoxine) is a required cofactor in the tryptophan-to-niacin reaction. Several therapeutic drugs can provoke pellagra.
Niacin deficiency is a consequence of a diet low in both niacin and the amino acid tryptophan, a precursor for the vitamin. Low plasma tryptophan is a non-specific indicator, meaning it can have other causes. The signs and symptoms of niacin deficiency start to revert within days of oral supplementation with large amounts of the vitamin. [23] [24]
About 1 in 4 Americans have too much niacin in their body from eating meats and nuts, but some people are still taking it as a supplement. Excess amounts of this B vitamin linked to higher heart ...
Also known as kynureninase deficiency, this extremely rare inherited disorder is caused by the defective enzyme kynureninase which leads to a block in the pathway from tryptophan to niacin (nicotinic acid). As a result, tryptophan is no longer a source of niacin, hence leading to pellagra (niacin deficiency).
Example of a label showing the amount of niacin (Vitamin B3), and specifying to be niacinamide in the ingredient section.. The United Stated adopted in 1942 the terms niacin to nicotinic acid and niacinamide to nicotinamide to avoid references to nicotine, [12] [13] the terms were incorporated into the United States Adopted Name [14] that was created later in 1961.
$8.22 at amazon.com. While you’ve probably heard of The Old Farmer’s Almanac, you may not know that it’s a publication that was founded by Robert B. Thomas in 1792 in Grafton, Massachusetts ...