Abstract Trimethylaminuria (TMAU) is a rare metabolic disorder resulting in the accumulation of trimethylamine (TMA), which is a foul-smelling metabolite that is excreted in bodily fluids and exudes ...a characteristic odour of rotting fish. Although the condition is not life-threatening, the psychological and social consequence can be devastating. Herein, we present the case of a 35-year-old woman with a diagnosis of TMAU. This case outlines the methods by which a diagnosis of TMAU can be made, while also magnifying the negative psychosocial impact of this rare diagnosis. It also reflects real-world experience with the currently available therapeutic options. TMA is produced in the gastrointestinal tract from dietary precursors such as choline (present in eggs, liver and poultry), trimethylamine N-oxide (TMAO; found in marine fish) and carnitine (found in meat). Primary trimethylaminuria is due to a mutation in the FMO3 gene, leading to the inability to oxidize this amine to the nonodorous metabolite (TMAO) (Antoñanzas J, Querol-Cisneros E, Alkorta-Aranburu G et al. Primary trimethylaminuria syndrome: more than an unpleasant odor. Int J Dermatol 2023; 62: e176–8). At present, over 40 variants in FMO3 associated with TMAU have been identified. Secondary or acquired TMAU is the result of a combination of factors including increased consumption of dietary precursors, gut dysbiosis, hepatic impairment and hormonal fluctuations resulting in an accumulation of TMA. Treatment regimens involve limiting precursors intake, using acidic soaps to reduce the volatility of excreted TMA, targeting gut microbiota, and the use of oral sequestering agents (Schmidt AC, Leroux JC. Treatments of trimethylaminuria: where we are and where we might be heading. Drug Discov Today 2020; 25: 1710–17). However, current treatment options have had limited therapeutic effect. Referral to metabolic specialists for correct nutritional support and referral to psychiatry is paramount for these patients. As evident from our patient’s viewpoint, this diagnosis can have a lifelong impact on social engagement and psychological health.
A 45-year-old woman provides her perspective on living with a rare disorder, trimethylaminuria, also known as ‘fish odour syndrome’. She describes the negative quality-of-life impact this diagnosis ...has had on her life, and feeling misunderstood and isolated with this diagnosis.
