Homocystinuria. Classical Homocystinuria, also known as cystathionine beta synthase deficiency or CBS deficiency,[1] is an inherited disorder of the metabolism of the amino acid methionine, often involving cystathionine beta synthase. It is an inherited autosomal recessive trait, which means a child needs to inherit a copy of the defective gene from both parents to be affected. Presentation[edit] This defect leads to a multisystemic disorder of the connective tissue, muscles, CNS, and cardiovascular system. Homocystinuria represents a group of hereditary metabolic disorders characterized by an accumulation of homocysteine in the serum and an increased excretion of homocysteine in the urine.
Infants appear to be normal and early symptoms, if any are present, are vague. Laboratory Diagnosis[edit] The term homocystinuria describes an increased excretion of the thiol amino acid homocystine in urine (and incidentally, also an increased concentration in plasma). Possible Signs and symptoms[edit] Treatment[edit] B vitamins. List of B vitamins[edit] Vitamin B1 (thiamine)Vitamin B2 (riboflavin)Vitamin B3 (niacin or niacinamide)Vitamin B5 (pantothenic acid)Vitamin B6 (pyridoxine, pyridoxal, or pyridoxamine, or pyridoxine hydrochloride)Vitamin B7 (biotin)Vitamin B9 (folic acid)Vitamin B12 (various cobalamins; commonly cyanocobalamin in vitamin supplements) B vitamin molecular functions[edit] B vitamin deficiency[edit] Several named vitamin deficiency diseases may result from the lack of sufficient B-vitamins.
B vitamin side effects[edit] Because water-soluble B vitamins are eliminated in the urine, taking large doses of certain B vitamins may produce transient effects. B vitamin sources[edit] B vitamins are found in whole unprocessed foods. The B12 vitamin is of note because it is not available from plant products, making B12 deficiency a legitimate concern for vegans. Another popular means of increasing one's vitamin B intake is through the use of dietary supplements. Related nutrients[edit] References[edit] HapMap Homepage.
Med student. The Journal of Nutritional Biochemistry - Dietary supplements of mixtures of indispensable amino acids lacking threonine, phenylalanine or histidine increase the activity of hepatic threonine dehydrogenase, phenylalanine hydroxylase or histidase, respecti. Received 18 July 2000; received in revised form 4 January 2001; accepted 9 January 2001. Experiments were carried out to determine whether the addition of a mixture of indispensable amino acids (IAA) lacking in threonine, phenylalanine or histidine, respectively, to a nutritionally complete diet would increase the hepatic activities of the rate-limiting enzymes for catabolism of threonine, phenylalanine or histidine and prevent the adverse effects of the amino acid on growth when the dietary level of the amino acid is excessive.
Week old Leghorn chicks were fed semi-purified diets containing 19% crude protein to which were added no IAA supplement or 10% crude protein from an IAA mix and 5 graded levels of either L-threonine, L-phenylalanine or L-histidine in a 2 × 5 factorial arrangement of treatments. Each amino acid was investigated in a separate experiment involving four replicate pens (seven chicks each) per diet. Molecular pathology - Human Molecular Genetics - NCBI Bookshelf. On the Biosynthesis of Cyclopenin and Cyclopenol, Benzodiazepine Alkaloids from Penicillium cyclopium Westling - Nover - 2005 - European Journal of Biochemistry.