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Tetrahydrobiopterin deficiency (THBD, BH 4 D) is a rare metabolic disorder that increases the blood levels of phenylalanine.Phenylalanine is an amino acid obtained normally through the diet, but can be harmful if excess levels build up, causing intellectual disability and other serious health problems.
PTPS deficiency is not necessarily its own disease. It shares history with PKU and hyperphenylalaninemia (HPA) . Asbjørn Følling, a physician studying metabolic diseases, identified an excess of phenylpyruvate as the cause of a strange, musty odor from the urine of two Norwegian children. [13]
Phenylketonuria (PKU)-like symptoms, including more pronounced developmental defects, skin irritation, and vomiting, may appear when phenylalanine levels are near 20 mg/dL (1200 mol/L). [1] Hyperphenylalaninemia is a recessive hereditary metabolic disorder that is caused by the body's failure to convert phenylalanine to tyrosine as a result of ...
Tyrosine is semi-essential; therefore, it can be synthesized by the animal, but only from phenylalanine. Phenylketonuria, a genetic disorder that occurs as a result of the inability to breakdown phenylalanine, is due to a lack of the enzyme phenylalanine hydroxylase. A dietary lack of tryptophan can cause stunted skeletal development. [9]
Hawkinsinuria is an autosomal dominant metabolic disorder affecting the metabolism of tyrosine. [1] [2] Normally, the breakdown of the amino acid tyrosine involves the conversion of 4-hydroxyphenylpyruvate to homogentisate by 4-hydroxyphenylpyruvate dioxygenase. Complete deficiency of this enzyme would lead to tyrosinemia III. In rare cases ...
Phenylalanine is a large, neutral amino acid (LNAA). LNAAs compete for transport across the blood–brain barrier (BBB) via the large neutral amino acid transporter (LNAAT). If phenylalanine is in excess in the blood, it will saturate the transporter. Excessive levels of phenylalanine tend to decrease the levels of other LNAAs in the brain.
Inborn errors of metabolism are often referred to as congenital metabolic diseases or inherited metabolic disorders. [2] Another term used to describe these disorders is "enzymopathies". This term was created following the study of biodynamic enzymology , a science based on the study of the enzymes and their products.
Tetrahydrobiopterin (BH 4, THB), also known as sapropterin (INN), [5] [6] is a cofactor of the three aromatic amino acid hydroxylase enzymes, [7] used in the degradation of amino acid phenylalanine and in the biosynthesis of the neurotransmitters serotonin (5-hydroxytryptamine, 5-HT), melatonin, dopamine, norepinephrine (noradrenaline), epinephrine (adrenaline), and is a cofactor for the ...