The Impact Of Trimethylaminuria On Patient’S Life

Abstract

Trimethylaminuria (fish odor syndrome) is an inherited disorder which is known for intolerable fishy odor. Humbert discovered the first case in 1970 and the number of incidents is still unknown. It is caused by genetic mutation in the gene FMO3 leading the chemical Trimethylamine to pile up in the human's body. There is no physical symptoms and the patient look healthy, but the only noticeable symptom is the strong noticeable malodor coming from different areas of the body such as the armpit, private areas (genitals organs), mouth breath, and saliva. Unfortunately, there is no cure for such disorder. The patients can follow a strict low protein diet to reduce the odor and by using a low PH soap.

However, following a low protein diet will cause a deficiency of protein that leads to many physical and psychological struggles in addition to the social pressure due to the unbearable smell. At the end, Trimethylaminuria (fish odor syndrome) is a metabolic disorder that can affect anyone. But Trimethylaminuria (TMAU) it can be cured by a certain strict diet and the use of certain hygienic products. IntroductionTrimethylaminuria (fish odor syndrome) is a metabolic genetic disorder that is caused by an inherited in an autosomal recessive mutation of FMO3 gene making the hepatic enzyme that breaks down the chemical Trimethylamin into the odorless trimethylamine-N-oxide. This mutation causes a disable to the enzyme leading to abnormal levels of trimethylamine in the human body. Humbert discovered the first case in 1970. In 2015, there are over 200 cases have been reported worldwide. There are two types of this disorder: primary Trimethylaminuria, which can be presented in early stages in life due to the genetic mutation, and secondary (transitory) Trimethylaminuria, which is caused by excess of proteins in a diet. Some patients may suffer from both types. Trimethylaminuria has strong genetic basis.

There are 18 mutations that relate to flavin-containing (FMO3) which is the main factor of Trimethylaminuria. In the primary Trimethylaminuria the symptoms are presented usually in childhood or early adulthood. TMAU symptoms Trimethylaminuria (fish odor syndrome) is commonly characterized by the malodor that is usually smelled like rotten fish in urine, sweat, breathe and saliva, and may get worse during puberty. In females, the smell is intense in the time of menstruation (monthly discharge of blood), and menopause. Besides TMAU, the excessive levels of Trimethylamine are associated with number of diseases such as renal disorders, cancer, obesity cardiovascular diseases, neuropsychiatric disorders (mental disorder)/. and diabetes, as a result, the patients are susceptible to those diseases. Although the patients appear physically and mentally healthy, the smell that may lead to psychological impact on the patient's life. In childhood, the patient would struggle with being ignored, humiliated, or bullied at school, causing an aggressive or unsettling behavior and learning difficulties and poor educational performance. A feeling of shame and embarrassment, which is the chief reason of low self-esteem. The avoidance of contacting with the society leading them to be social isolated, lonely, frustrated and depressed. In adulthood, patients face difficulties in starting or maintaining relationships. In extreme cases, patients probably have paranoid attitude and suicide tendencies.

Trimethylaminuria cannot be determined by the examiner's sense of smell because of the presence of the odor is often periodic. In addition, the human nose can easily trimethylamine, some people are able to identify concentration as low as 1 part in 109, and some people are unable to detect the smell of trimethylamine. Also, the reason of the odor might be caused by other compounds other than trimethylamine.

There are two tests to diagnose Trimethylaminuria, one of them is urinary excretion. Usually the test can be done under normal dietary condition, it might help to eat a meal that is full in choline (e. g. eggs, soya beans and red meat) before the test. Note that women should not be tested during menstruation. The urinary excretion of trimethylamine is measured as one of the following:

First, percent of total trimethylamine (TMA) (i. e. , free TMA plus the non-odorous metabolite TMA N-oxide) excreted in the urine as unmetabolized free TMA ◦Severe trimethylaminuria: >40% of total TMA excreted as unmetabolized free TMA◦Mild trimethylaminuria: 10%-39% of total TMA excreted as unmetabolized free TMA◦Unaffected: 0%-9% of total TMA excreted as unmetabolized free TMASecond, concentration of unmetabolized TMA in the urine. A urinary concentration of free TMA of 10 µg/mL (18-20 µmol/mmol creatinine) or higher, correlating with a urinary output of TMA of ~15-20 mg/day, appears to represent a threshold for the presence of the fishy body odor associated with the disorder.

The other test is molecular genetic test that consists of single-gene testing. Trimethylaminuria is an inherited in an autosomal receiver aspect. The parents of the patient are compelled heterozygotes (an individual having two different alleles which is a mutation of a different form of a gene and found at the same place on a chromosome).

First, the examiner preforms a sequence analysis of FMO3 then follows it with a gene-targeted deletion/duplication analysis if only one or no pathogenic variant (a change in a gene related to abnormal phenotype or increased in disease risk) is found. The proportion of probands with pathogenic variants that are found by gene-targeted deletion/duplication analysis are unknown because there was only one case of Trimethylaminuria reported for a FMO3 pathogenic variant due to a large deletion. TMAU treatmentIt is necessary for the patients to be aware of their condition and follow a strict treatment strategies and diet. There is no best therapy for TMAU, once a person is diagnosed with TMAU a change in lifestyle must occur. A restricted low protein diet consists of avoiding marine fish, as it is the main dietary modality, but it should not be hard for the patients to avoid. Also, certain proteins called choline ( found in eggs, liver, kidney, peas, beans, soy beans, Brussel sprouts), lecithin (found in egg yolk, soya beans and fish oil supplements), carnitine (found in red meat and dairy product). Furthermore, if the milk was obtained from wheat - fed cows, it might have small amount of trimethylamine thus it is better to avoid it. However, fresh water fish have lower content trimethylamine-N-oxide, so it is not a problem.

Unfortunately, this restricted protein diet will lead to many dietary deficiencies, and it will affect their healthy and daily life especially for pregnant women, as choline is a very important source for growth of nerves and brain for the fetus. Unfortunately, there must be no restriction of choline during pregnancy. This diet would cause protein malnutrition that will result in stunting, anemia, physical weakness, edema (a condition which portray by an excess of watery fluid accumulating in the cavities or tissue ), endothelial dysfunction ( is a shift in the properties of endothelium toward a phenotype characterized by impaired vasodilation and proinflammatory prothrombic status), damaged immunity also lack of protein will result in vitamins D deficiency causing calcium malabsorption, increases the risk of obesity, type 2 diabetes and cardiovascular disease and hyper tension. Overall, lack of nutrient would lead to severe depression, crankiness and moodiness, anxiety and a decrease of energy. The proteins restriction must be prescribed carefully and with consideration of the patient health condition. At the end, the patient must consume 4-8% (20-50 gram) of their daily calories from protein. In addition to dietary treatment, hygiene is important as well. The use of certain soaps and body lotions with a pH close to that of normal skin (pH 5. 5-6. 5) helps keep produce trimethylamine in a less vaporous salt form than can be removed by washing. Also using activated charcoal and copper chlorophyllin segregate trimethylamine produced in the guts, and consuming Riboflavin supplements to increase the production of FMO3 enzyme. Patients also should avoid some elements that develop sweating such as high intensity physical exercise, stress and emotional outdoors, and stay away from hot beverages.

Conclusion

As a result, Trimethylaminuria (fish odor syndrome (TMAU) is a rare life-disruptive disorder that is related to 17 genetic mutations and has no definitive cure. It does not have any physical symptoms, it only has a fishy smell in breath, sweat, urine and other body fluids because of unoxidized trimethylamine secreted by the body. Patients face psychic impacts due to the unbearable smell. They struggle alot with social pressure which leads them to be isolated and separated from the society and may affect their academic performance. Luckily, the symptoms can be decreased by following a low protein diet and using certain products that contains low Ph rate, but the down side of the diet is that the patient would suffer from the lack of protein causing them body weakness and multiable diseases concerning the blood and the heart and diabetes. In addition to the physical effects, the mental effect is equally important. Patients encounter with depression, anxiety and mood changes.