Is There A Cure for Fish Odor Syndrome?

Fish odor syndrome or trimethylaminuria is a condition characterized by a fishy body odor that is released in the sweat, urine, breath and reproductive fluids due to excessive excretion of trimethylamine. People with this condition cannot break down trimethylamine, a chemical found in certain foods. Excess trimethylamine is the cause of the fishy odor or rotten fish odor.

Besides the fishy odor, patients may also experience the following symptoms:

• Anemia
• Depression
• Hypertension
• Neutropenia (low blood neutrophil count)
• Recurrent pneumonia
• Splenomegaly (an increased spleen size)
• Tachycardia (an increased heart rate)
• High urine trimethylamine level
• Low self-esteem
• Anxiety
• Social isolation

The aforementioned symptoms may not be experienced by all and vary from person to person.

The fishy odor may get worse with increased sweating, exercising, and emotional stress. In women, the symptoms may worsen during

• Menstruation
• Taking oral contraceptives
• Menopause

The odor may vary from person to person and can interfere with daily aspects of life, leading to social or psychological problems.

Fish odor syndrome is caused by a deficiency in FMO3 genes. Under normal conditions, the trimethylamine precursors (choline) obtained from the food is reduced to trimethylamine by colonic bacteria. This trimethylamine then diffuses through the cell membranes to reach the liver, and the FMO3 in the liver oxidizes trimethylamine into odorless trimethylamine-N-oxide; however, people having fish odor syndrome fail to metabolize trimethylamine due to lack of FMO3 genes, leading to the buildup of trimethylamine.

People inherit fish odor syndrome by an autosomal recessive pattern, which means both the copies of the gene obtained from parents have mutations. Both the parents may each carry one copy of mutated genes (carriers), although they do not show any signs or symptoms. In some conditions, the carriers may exhibit mild or occasional symptoms. When two carriers of an autosomal recessive condition have children, there is a 25% chance to have a child with fish odor syndrome.

Fish odor syndrome is usually diagnosed based on the symptoms, a clinical examination, and a test to measure the level of trimethylamine in the urine. Genetic testing can help to diagnose fish odor syndrome.