Fish-odor syndrome

There is also a genetic deficiency in FM03 in humans leading to Fish Odor syndrome, which results from the inability of the afflicted individuals to metabolism trimethylamine, which has a strong fishy smell, to the N-oxide, which has no smell. 

Five forms of FMO are found in humans (and several experimental animals). Important physiological substrates have not been established, although some possibilities have been proposed (Ziegler, 1993). An interesting polymorphism involves defects in FMO 3, giving rise to deficient metabolism of trimethylamine and a resulting fish-odor syndrome (Al-Waiz et al., 1987). In contrast to P450, FMOs appear not to be inducible or readily inhibited. 

Eugene, M. (1998) [Diagnosis of fish odor syndrome by urine nuclear magnetic resonance proton spectrometry]. Ann Dermatol Venereol 125, 210-212. 

Mitchell, S. C. (1996) The fish-odor syndrome. Perspect Biol Med 39, 514-526. 

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