Premium
Marked Amine and Amine Metabolite Changes in Norrie Disease Patients with an X‐Chromosomal Deletion Affecting Monoamine Oxidase
Author(s) -
Murphy D. L.,
Sims K. B.,
Karoum F.,
Chapelle A.,
Norio R.,
Sankila E.M.,
Breakefield X. O.
Publication year - 1990
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1990.tb13307.x
Subject(s) - monoamine oxidase , tyramine , metabolite , monoamine oxidase a , monoamine oxidase b , biogenic amine , monoamine neurotransmitter , dopamine , serotonin , isozyme , endocrinology , medicine , chemistry , biology , biochemistry , enzyme , receptor
Urinary and plasma amines and amine metabolites were quantified in two individuals with Norrie disease resulting from a deletion in chromosomal region Xp 11.3, recently reported to be associated with absence of the gene encoding monoamine oxidase (MAO)‐A and nondetectable MAO‐A activity in fibroblasts and MAO‐B activity in platelets. Marked (four‐ to 100‐fold) elevations in levels of urinary phenylethylamine, o ‐tyramine, and m ‐tyramine (which are preferential substrates for MAO‐B) and marked reductions (90%) in levels of 3‐methoxy‐4‐hydroxyphenylglycol (a deaminated metabolite of norepinephrine, a preferential substrate for MAO‐A) in urine and plasma confirmed the presence of a systemic, functionally significant reduction in the activities of both MAO isozymes. The magnitude of these changes, which are equivalent to those found in subjects taking MAO‐inhibiting antidepressants, suggests that early initiation of dietary and drug restrictions may be clinically important in these and other patients with X‐chromosomal mutations involving MAO. These findings further support the proposition that the MAOA and MAOB genes are located in close proximity on the X chromosome. Negligible changes in the metabolites of dopamine and serotonin raise the possibility that other metabolic pathways are of importance for their production, that dietary or intestinal bacterial sources contribute substantially to the presence of these amine metabolites in urine, or both.