Volume 189 - Issue 8
Trimethylaminuria (fish malodour syndrome): a “benign” genetic condition with major psychosocial sequelae
Authors: Helen Mountain, Joanna M Brisbane, Amanda J Hooper, John R Burnett and Jack Goldblatt
Med J Aust 2008; 189 (8): 468. || doi: 10.5694/j.1326-5377.2008.tb02126.x
Published online: 20 October 2008
Published online: 20 October 2008
To the Editor: We report the case of a 41-year-old woman who sought medical opinion about an unpleasant body odour, first noticed when she was 7 years old. After experiencing ridicule, distress, shame, anxiety and low self-esteem during her school years, she first consulted a doctor about the problem at the age of 17 years, then again 2 years later, followed by a further four doctors over the next 20 years. All dismissed her concerns, and she was repeatedly told that she had a hygiene neurosis. Investigations and treatments during this time included being “sniffed”, vaginal swabs and vaginal cauterisation. Finally, a general practitioner referred her to a dermatologist, who consulted a microbiologist, and the diagnosis of trimethylaminuria (TMAU), or fish malodour syndrome, was confirmed by urinalysis. Now having a name for her condition, she found an Internet-based support foundation and referred herself for genetic counselling.
TMAU is caused by an enzyme deficiency due to mutations in the flavin-containing mono-oxygenase 3 (FMO3) gene,1 resulting in excess excretion of trimethylamine in urine, sweat and breath. It is diagnosed by clinical symptoms and urine analysis.2 The characteristic body odour resembling rotting fish can be intermittent, variable and influenced by diet, hormones and medications. Restriction of choline- and carnitine-rich dietary precursors (eg, fish, eggs, soybeans, peas) is difficult to maintain and effective in only 25% of patients.2 Acid soaps and body lotions can often reduce the odour.3 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, can have important ramifications including missed or delayed diagnosis.4
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.4, Psychosocial problems resulting from delayed diagnosis, body odour and the lack of cure are considerable, making this a far from “benign” disorder.
Recognition of TMAU as a significant clinical entity and increased understanding of the issues patients face are needed. Awareness of the typical patient history would facilitate prompt metabolic diagnosis and pre-empt some of the associated psychosocial sequelae. Referral of patients for genetic counselling enables short-term psychosocial support and family cascade genetic testing. Consultation with a metabolic clinic for dietary management may also be beneficial.
References
- Treacy EP, Akerman BR, Chow LM, et al. Mutations of the flavin-containing monooxygenase gene (FMO3) cause trimethylaminuria, a defect in detoxification. Hum Mol Genet 1998; 7: 839-845. 0_CBBFIEJD
- Mitchell SC, Smith RL. Trimethylaminuria: the fish malodor syndrome. Drug Metab Dispos 2001; 29: 517-521. 0_CBBHGEDI
- Wilcken B. Acid soaps in the fish odour syndrome [letter]. BMJ 1993; 307: 1497. 0_CBBBIHHA
- Walker V. The fish odour syndrome. BMJ 1993; 307: 639-640. 0_i1091853
- Ayesh R, Mitchell SC, Zhang A, Smith RL. The fish odour syndrome: biochemical, familial, and clinical aspects. BMJ 1993; 307: 655-657. 0_pgfId-1878798
Shifting focus to adolescent wellbeing and inclusive participation in the digital age
Allyson R Todd, Elena Wang, Stephanie R Partridge
The clinical presentation, investigation, and management of women diagnosed with endometriosis in Australian general practices, 2011–2021: an open cohort study
Danielle Mazza, Kailash Thapaliya, Sharinne B Crawford, Alissia Hui, Maryam Moradi, Luke E Grzeskowiak
The impact of the Breast Screen NSW transition from film to digital mammography, 2002–2016: a linked population health data analysis
Rachel Farber, Nehmat Houssami, Katy J L Bell
Non‐technical errors associated with deaths in surgical care, Australia, 2012–2019, by surgical specialty (Australian and New Zealand Audit of Surgical Mortality): a retrospective cohort study
Jesse Ey, Victoria Kollias, Octavia Lee, Kelly Hou, Matheesha Herath, John B North, Ellie Treloar, Suzanne Edwards, Martin Bruening, Adam J Wells, Guy J Maddern
The CURE Asthma roadmap
Gary P Anderson, Anthony Flynn, Phil G Bardin, John D Blakey, Shyamali C Dharmage, Paul Foster, Peter G Gibson, Adam Jaffe, Alan James, Christine R Jenkins, Sundram Sivamalai, Peter D Sly, Guy B Marks, Vanessa M McDonald, Judy Wetttenhall
Evidence from Australian cohort studies about asthma trajectories and transitions across the life course: a narrative review
Caroline Lodge, Xin Dai, Ingrid A. Laing, Michael P Menden, Anthony Flynn, Gary P Anderson, Sarath Ranganathan, Shyamali C Dharmage