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Tyrosine hydroxylase deficiency; Simplified overview of the biosynthesis and catabolism of serotonin and the catecholamines, with tyrosine hydroxylase (TH) and its cofactor tetrahydrobiopterin (BH 4) circled in red. Note that different parts of these processes take place in different tissues.
Tyrosine hydroxylase or tyrosine 3-monooxygenase is the enzyme responsible for catalyzing the conversion of the amino acid L-tyrosine to L-3,4-dihydroxyphenylalanine (L-DOPA). [ 5 ] [ 6 ] It does so using molecular oxygen (O 2 ), as well as iron (Fe 2+ ) and tetrahydrobiopterin as cofactors .
Sometimes a lumbar puncture is performed to measure concentrations of biopterin and neopterin, which can help determine the exact form of dopamine-responsive movement disorder: early onset parkinsonism (reduced biopterin and normal neopterin), GTP cyclohydrolase I deficiency (both decreased) and tyrosine hydroxylase deficiency (both normal).
The sex steroid deficiency produces effects similar to 17α-hydroxylase deficiency. Severely affected genetic females (XX) are born with normal internal and external genitalia and there are no clues to abnormality until adolescence, when the androgenic and estrogenic signs (e.g., breasts and pubic hair) of puberty either fails to occur or is ...
Late onset CAH was originally characterized in 1957 by French biochemist Jacques Decourt, [126] but the association with mild 21-hydroxylase deficiency called nonclassical 21-hydroxylase deficiency, which is characterized by diverse hyperandrogenic symptoms appearing postnatally in males and females, was first described in 1979 by Maria New. [127]
The symptoms of isolated 17,20-lyase deficiency, in males, include pseudohermaphroditism (i.e., feminized, ambiguous, or mildly underdeveloped (e.g., micropenis, perineal hypospadias, and/or cryptorchidism (undescended testes)) external genitalia), female gender identity, and, in non-complete cases of deficiency where partial virilization occurs, gynecomastia up to Tanner stage V (due to low ...
Tyrosine hydroxylase is the rate limiting enzyme responsible for the transformation of L-Tyrosine to L-3,4-dihydroxyphenylalanine , a catecholamine precursor. Catecholamines, dopamine , epinephrine , and norepinephrine , signal different stressors so the body can activate pathways to return towards homeostasis.
17α-hydroxylase deficiency; 17,20 lyase deficiency; 17β-hydroxysteroid dehydrogenase deficiency; 5α-reductase deficiency; Androgen excess in 46,XX individuals: 21-hydroxylase deficiency; 3β-hydroxysteroid dehydrogenase 2 deficiency; Cytochrome P450 oxidoreductase deficiency (disorder in mother causes 46,XX fetal virilization) 11β ...