Taste and smell function in Wolfram syndrome

M. Yanina Pepino,Tamara Hershey,Heather Lugar,Raul Alfaro,Anagha Narayanan,Tasha Doty

doi:10.1186/s13023-020-1335-7

M. Yanina Pepino, Tamara Hershey + Show 4 more

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https://doi.org/10.1186/s13023-020-1335-7

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Abstract

BackgroundWolfram syndrome is a rare genetic disease characterized by insulin-dependent diabetes, optic nerve atrophy, sensorineural hearing loss and neurodegeneration. Although olfactory dysfunction, a classical clinical marker of neurodegenerative processes, has been reported in Wolfram syndrome, its use as a clinical marker in Wolfram is limited due to data scarcity. In addition, it is unknown whether Wolfram syndrome affects the sense of taste.MethodsSmell and taste perception were assessed in participants with Wolfram syndrome (n = 40) who were 15.1 ± 6.0 years of age (range: 5.1–28.7 years) and two sex- and age-matched control groups: one group with type 1 diabetes mellitus (T1D; n = 25) and a healthy control group (HC; n = 29). Smell sensitivity was assessed by measuring n-butanol detection thresholds and smell identification by using the University of Pennsylvania Smell Identification Test (UPSIT). Taste function was assessed using NIH Toolbox, which includes the assessment of sucrose (sweet) taste preference, and perceived intensity of sucrose, sodium chloride (salty), and quinine hydrochloride (bitter) both in the tip of the tongue (regional test) and the whole mouth.ResultsSmell sensitivity was not significantly different among groups; however, smell identification was impaired in Wolfram syndrome, as reflected by significantly lower UPSIT scores in Wolfram syndrome compared to HC and T1D (P < 0.001). Compared to participants in the control groups, participants with Wolfram syndrome had a blunted perception of sweetness and saltiness when taste stimuli were applied regionally (P < 0.05), but differences in perceived intensity were no longer significant among groups when taste stimuli were tasted with the whole mouth. Groups preferred similar sucrose concentrations.ConclusionWolfram syndrome was associated with olfactory dysfunction. However, the olfactory dysfunction was qualitative (related to smell identification) and not secondary to olfactory insensitivity or diabetes, suggesting is arising from dysfunction in central olfactory brain regions. In contrast to olfaction, and despite decreased perception of taste intensity in the anterior tongue, the sense of taste was overall well-conserved in individuals with Wolfram syndrome. Future longitudinal studies of taste and smell perception in Wolfram syndrome will be important to determine the use of the chemical senses as clinical markers of disease progression.

Highlights

Wolfram syndrome is a rare genetic disease characterized by insulin-dependent diabetes, optic nerve atrophy, sensorineural hearing loss and neurodegeneration
Using the University of Pennsylvania Smell Identification Test (UPSIT), we previously reported that 72% of patients with Wolfram syndrome had olfactory defects [20]
Olfactory sensitivity There were no significant differences between groups for n-butanol detection thresholds (Mean ± SEM; healthy control group (HC): 8.4 ± 0.8; type 1 diabetes mellitus (T1D): 7.6 ± 0.8 and Wolfram syndrome: 7.3 ± 0.4; F (2, 72) = 0.82, P = 0.44) or the percentage of participants in each group whose detection threshold was below the 10th percentile for age and sex matched normative data (P > 0.49; Fig. 1)

Summary

Introduction

Wolfram syndrome is a rare genetic disease characterized by insulin-dependent diabetes, optic nerve atrophy, sensorineural hearing loss and neurodegeneration. A classical clinical marker of neurodegenerative processes, has been reported in Wolfram syndrome, its use as a clinical marker in Wolfram is limited due to data scarcity. It is unknown whether Wolfram syndrome affects the sense of taste. Wolfram syndrome is a rare genetic disease with an estimated prevalence of 1 in 770,000 [1] caused by mutations in the genes WFS1 [2] or, less commonly, WFS2 [3]. Olfactory dysfunction has been associated with Wolfram syndrome in clinical reports [16,17,18,19] data from standardized tests measuring sense of smell is very limited. Because UPSIT measures only how well an individual can identify odorants, it is unknown whether the Wolfram syndrome group’s UPSIT performance is secondary to impairments in the peripheral nervous system (smell sensitivity), solely due to impairment at the central level (smell identification), or a combination of both [22]

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