Genetic diseases can be diagnosed using a variety of methods: physical exam, personal/family medical history, or tests performed in a laboratory. But, did you know that smells can also be used to make a diagnosis for some genetic diseases? It’s true!
Smells are caused by small, unstable compounds that activate the olfactory receptors in your nose. These compounds can often be detected in extremely small concentrations. There are several genetic diseases that prevent an individual’s body from breaking down certain compounds. When these compounds build up in the body, they can cause specific smells!
Here are a few genetic diseases known to have an associated smell that can be helpful in establishing a diagnosis:
Trimethylaminurea
Trimethylaminuria (TMAU) is a rare genetic disorder that causes a distinctive fish-like body odor. The odor occurs when unusually high levels of trimethylamine (TMA) are released in the urine, breath, and sweat. The odor is described as smelling like rotting fish or rotting eggs. A diet avoiding foods with high levels of TMA can improve this odor.
Maple syrup urine disease
Maple syrup urine disease (MSUD) is an inherited metabolic disorder named after the hallmark maple syrup odor of the urine. This unique odor is caused by an accumulation of amino acids in the urine. Treatment for MSUD is through dietary restriction of branched-chain amino acids. With treatment, affected individuals may remain healthy and live through adulthood.
Phenylketonuria
Phenylketonuria (PKU) is a rare genetic disorder in which people lack a substance in the body called phenylalanine hydroxylase (PAH). This deficiency causes elevated phenylalanine levels in the body. One of the unique features of PKU is a “mousy” or “musty” odor to the skin, hair, sweat and urine due to the elevated phenylalanine levels.
Isovaleric acidemia
Isovaleric acidemia (IVA) is a genetic disorder that causes a buildup of certain acids in the body, called organic acids. One of the unique features of isovaleric acidemia is a “sweaty foot” odor of the person with this condition when they are sick.
Although these diseases are each associated with a specific smell, it’s important to remember that they are also accompanied by other signs and symptoms and require the examination and treatment by a geneticist and/or other healthcare providers. You can find additional information about these genetic diseases on the ThinkGenetic website. It may also be helpful to contact a genetic counselor near you using the NSGC find a genetic counselor webpage.
About Morgan Simmons – Morgan received her master’s degree in human genetics and genetic counseling from Emory University in 2017 and is currently a genetic counseling fellow at the Emory University Lysosomal Storage Disease Center and a ThinkGenetic contributor.
Very informative!
Thank you, Michelle!
Thank you for this article on a subject that needs more awareness. Two of my children have Isovaleric Acidemia and had medical professionals known that the smell exhibited at 18 months and again at age 3 1/2, my son Stephen , now 19, was associated with Isovaleric Acidemia , his brain injury could have been prevented.
http://www.aphlblog.org/2013/05/two-siblings-born-with-isovaleric-acidemia-one-caught-with-newborn-screening-one-wasnt/
You’re very welcome, Jana! We at ThinkGenetic hope that by increasing awareness we will be able to encourage earlier diagnoses for conditions such as isovaleric acidemia. I’m so sorry to hear about your son, but I wish you and your family the best.
This was very helpful. For the last 9 years I’ve had symptoms of TMAU and I’ve been to doctor after doctor after doctor to get help but they’re not helping me. I need a geneticist asap as this is affecting all aspects of my life professional, social, etc. It goes without saying I’m depressed from this as well.
We’re sorry to hear about your health concerns. We’ve had several people reach out to us in the past with questions about TMAU due to breath odor. This can be diagnosed in a few ways, one of which is seeing a geneticist. To find a geneticist near you, you can use the following website: https://www.acmg.net/ACMG/Find_Genetic_Services/ACMG/ISGweb/FindaGeneticService.aspx
It may also be beneficial to connect to the Mebo Research group at https://www.meboresearch.org/. They’ve had some TMAU testing opportunities in the past and they may have more in the future. The Mebo blog also has suggestions people with TMAU have tried to combat odor.
Unfortunately, even if someone is diagnosed with TMAU treatment is typically still symptom-based to the best of our knowledge. People generally try elimination diets to relieve some of the symptoms including avoiding foods that contain trimethylamines like milk from wheat-fed cows, eggs, peanuts, beans, broccoli, saltwater fish, shrimp, and cauliflower. Several people have had some success using hunter’s soaps such as Scent-A-Way.
Please remember that information presented on these sites should not be taken as medical advice. You should always talk about the information presented on the site or by members you interact with from these sites with your healthcare providers. Please consult your doctor before making changes to your diet.
We hope this helps and wish you all the best in your search to find answers,
Jessica Dronen
Genetic Diseases Research and Information Specialist
ThinkGenetic