Persistent body malodor can cause great psychosocial distress to patients. One of the most pungent is the "fish odor" syndrome, or trimethylaminuria. In this condition, metabolism of food constituents such as choline and carnitine to trimethylamine N-oxide is impaired. As a result, the urine, sweat, breath and body secretions contain trimethylamine. This amine smells strongly of rotting fish and can be detected by the human nose at concentrations less than one part per million. Although approximately 1 percent of the population may be affected, little is known about this condition. Ayesh and colleagues used interest generated by a British newspaper article on the syndrome to learn more about the condition, particularly its mode of inheritance.
Following the newspaper article, 187 letters of inquiry were received from people who suspected they or their children had the syndrome. These individuals were asked to provide two urine samples for trimethylamine excretion assessment: the first a 24-hour collection under normal dietary conditions and the second an eight-hour collection following an oral challenge test with 600 mg of trimethylamine.
Eleven cases of trimethylaminuria were clinically and biochemically confirmed. These six females and five males ranged in age from infancy to 70 years and were all in good general health. A variety of adverse psychosocial reactions was reported, including depression, difficulties with relationships and career advancement, substance abuse and paranoia.
The parents of six of the 11 patients originally identified were also tested. All of the parents showed impaired trimethylamine metabolism after oral challenge, suggesting heterozygous characteristics in the carrier.
The authors conclude that the fish odor syndrome can be inherited as an autosomal recessive condition and that the malodor may cause severe distress to patients. To manage the problem, they recommend reducing carnitine and choline in the patient's diet, prescribing neomycin and metronidazole, and informing the patient that certain events might exacerbate the problem, including menstruation, fever or stress. (BMJ, September 11, 1993, vol. 307, p. 655.)
COPYRIGHT 1994 American Academy of Family Physicians
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