Fishy smelling urine is a primary identifying symptom in infant children (Trimethylaminuria literally meaning "trimethylamine in urine"). Trimethylamine is also released in the persons sweat, reproductive fluids, and breath, and can give off a fishy odor when the concentration of trimethylamine is high enough to be detected. The intensity of the smell is directly correlated with the concentration of trimethylamine in the bloodstream. Some people with trimethylaminuria report having a strong odor all the time, but when in a clinical setting most have only moderate to no smell, depending on diet and the severity of their FM03 mutation. In a study by Wise PM, of 115 identified tmau subjects, 0% had a smell detectable at a social distance and only 5% had some minor malodour when sniffing their palms. After a choline challenge load test (intentionally ingesting a TMA precursor) only 10% expressed a smell at a social distance, suggesting that those that produced odour had a more severe form of FMO3 impairment. Smell events are often sporadic and episodic in nature (based on diet over the previous 24 hours), making it often difficult to diagnose by smell alone. Individuals with this condition do not have any physical symptoms, and they typically appear healthy.The condition seems to be more common in women than men, for unknown reasons. Scientists suspect that such female sex hormones as progesterone and estrogen aggravate the condition. According to several reports, the condition worsens around puberty.
Treatment
There is no known permanent cure or treatment for primary trimethylaminuria, only mitigation of the effects. For secondary trimethylaminuria, it depends on the cause; for precursor overload, reducing the intake of TMA and its precursors will end symptoms. For TMAU caused by hypothetical gut dysbiosis, clinical review by a doctor, a plant based diet and reduced precursor intake should return gut flora to a healthy state.Primary TMAU sufferers generally have some residual FMO3 activity in the liver which processes TMA, however this happens relatively slowly. According to a study by Al-Waiz M TMA filters through to the bladder at half the rate of TMAO, and a healthy functioning person passes 99% of TMAO in urine within 24 hours. Therefore its estimated that the majority of TMA would be filtered out within 48 hours if no additional TMA or precursor is ingested, regardless of liver function. The metabolic and clinical manifestations of TMAU are generally regarded as benign, as there is no associated organ dysfunction. This designation, and the fact that the condition is often unrecognised by doctors, misdiagnosed and can have important ramifications including missed or delayed diagnosis.Affected individuals experience shame and embarrassment, fail to maintain relationships, avoid contact with people who comment on their condition, and are obsessive about masking the odour with hygiene products and even smoking. The malodorous aspect can have serious and destructive effects on schooling, personal life, career and relationships, resulting in social isolation, low self-esteem, depression, paranoid behaviour, and suicide.