Study Finds Smell, Taste Impaired in Patients With Wolfram Syndrome

Researchers determined patients with Wolfram syndrome have impaired smell identification abilities and blunted perceptions of certain taste stimuli, according to a study published in the Orphanet Journal of Rare Diseases.

Wolfram syndrome is a genetic disease in which patients exhibit insulin-dependent diabetes, optic nerve atrophy, sensorineural hearing loss, and neurodegeneration. Approximately 1 in 770,000 people have Wolfram syndrome worldwide. Although a common clinical marker of neurodegenerative diseases is olfactory disfunction, currently there are only limited data from standardized tests measuring the symptom in Wolfram syndrome.

To test whether the neurodegenerative disease affected olfactory dysfunction, researchers had 40 patients and 2 sex- and age-matched control groups complete the University of Pennsylvania Smell Identification Test (UPSIT). One control group was comprised of individuals with type 1 diabetes (T1D) and the other control group was healthy.

In order to assess taste function in participants, researchers used the National Institutes of Health Toolbox. This test is used to assess sucrose (sweet) taste preference and measure perceived intensity of sucrose, sodium chloride (salty), and quinine hydrochloride (bitter) tastes both on the tip of the tongue (regional test) and the patient’s whole mouth.

Overall, patients with Wolfram syndrome scored significantly lower on UPSIT than those with T1D and healthy controls (P <.001). This led researchers to conclude that patients with Wolfram syndrome had impaired abilities to identify smells. Smell sensitivity was not significantly different among all 3 groups.

In addition, “patients with Wolfram syndrome had a blunted perception of sweetness and saltiness when taste stimuli were applied regionally (P <.05),” researchers said. They continued, “differences in perceived intensity were no longer significant among groups when taste stimuli were tasted with the whole mouth.”

Researchers hope that by identifying the impact of the disease on taste and smell, these biomarkers could be used to evaluate the progression of the disease and measure effectiveness of potential treatments.

“Wolfram syndrome was associated with qualitative olfactory dysfunction that was not secondary to olfactory sensitivity or diabetes,” researchers concluded. In the future, longitudinal studies on taste and smell perception should be conducted in patients with Wolfram syndrome, so as to potentially use chemical senses as clinical markers to determine disease progression.

Reference

Alfaro R, Doty T, Narayanan A, et al. Taste and smell function in Wolfram syndrome. Orphanet J Rare Dis. 2020;15(57). doi: 10.1186/s13023-020-1335-7.