Parosmia (from the Greek παρά pará and ὀσμή osmḗ "smell") is a dysfunctional smell detection characterized by the inability of the brain to correctly identify an odors "natural" smell. Instead, the natural odor is usually transformed into an unpleasant aroma, typically a "burned", "rotting", "fecal", or "chemical" smell. There can also be rare instances of a pleasant odor called euosmia. The condition was rare and little-researched until it became relatively more widespread since 2020 as a side effect of COVID-19. Causes
There are numerous diseases with which parosmia is associated. In a case study, Frasnelli et al. examined five patients that endured parosmia or phantosmia, most as a result of upper respiratory tract infections (URTIs). It is hypothesized that URTIs can result in parosmia because of damage to olfactory receptor neurons (ORNs). The condition has been linked to coronavirus disease 2019 as a rare side effect. Common triggers in COVID-19 related parosmia include coffee, chocolate, meat, onion and toothpaste. Exposure to harmful solvents has also been linked to parosmia, specifically by damaging ORNs. Damage to these neurons could render them unable to correctly encode a signal representing a particular odor, which would send an erroneous signal to the odor processing center, the olfactory bulb. This, in turn, leads to the signal triggering a different smell than the stimulating odor, and thus the patient cannot sync the input and output odors.
Some women will develop this in adulthood. Cardiomyopathy can be associated with atrial fibrillation and embolic strokes. Cardiac conduction abnormalities can occur. Wolff-Parkinson-White syndrome is a common conduction pattern in Danon disease. Symptoms in females progress more slowly than in males. Some females may have visual disturbances, and/or retinal pigment abnormalities
Danon Disease is rare and unfamiliar to most physicians. The milder and more subtle symptoms in females can make it more difficult to diagnose females with Danon Disease

Causes
Although the genetic cause of Danon Disease is known, the mechanism of disease is not well understood. Danon disease involves a genetic defect (mutation) in a gene called LAMP2, which results in a change to the normal protein structure. While the function of the LAMP2 gene is not well understood, it is known that LAMP2 protein is primarily located in small structures within cells called lysosomes. Genetics
It is associated with LAMP2. The status of this condition as a GSD has been disputed. Diagnosis
Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a persons medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional. Testing Resources
The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers.