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Olfactory dysfunction in type I pseudohypoparathyroidism: dissociation from Gs alpha protein deficiency
R L Doty1, A D Fernandez, M A Levine
1Smell and Taste Center, School of Medicine, University of Pennsylvania, Philadelphia 19104, USA.
The Journal of Clinical Endocrinology and Metabolism
|January 1, 1997
Summary
Olfactory dysfunction is present in Type Ia pseudohypoparathyroidism (PHP) patients. However, this olfactory deficit is not solely due to Gs alpha deficiency, suggesting other mechanisms are involved in PHP-related smell impairment.
Area of Science:
- Endocrinology
- Neuroscience
- Genetics
Background:
- Type Ia pseudohypoparathyroidism (PHP) involves hormone resistance linked to Gs alpha deficiency.
- Previous findings suggested Gs alpha's role in olfactory transduction due to olfactory deficits in PHP Ia patients.
- Potential confounding factors like Albright hereditary osteodystrophy (AHO) in PHP patients were not fully explored.
Purpose of the Study:
- To investigate the role of Gs alpha protein in human olfactory transduction.
- To differentiate olfactory dysfunction causes in PHP Type Ia, Type Ib, and pseudopseudohypoparathyroidism (PPHP).
- To assess if Gs alpha deficiency or other factors contribute to olfactory deficits in PHP.
Main Methods:
- Administered odor detection, identification, and memory tests.
- Included 13 patients with PHP Type Ia, 8 with PHP Type Ib, and 7 with PPHP.
- Utilized matched normal controls for comparison.
Main Results:
- Confirmed olfactory dysfunction in PHP Type Ia patients.
- Demonstrated olfactory dysfunction in PHP Type Ib patients, who lack AHO and generalized hormone resistance.
- Showed relatively normal olfactory function in PPHP patients, despite AHO and deficient Gs alpha protein.
Conclusions:
- The olfactory dysfunction in PHP is not solely caused by generalized Gs alpha protein deficiency.
- Findings suggest alternative mechanisms, potentially related to parathyroid hormone (PTH) or PTH-related peptide (PTHrP) resistance, underlie olfactory deficits in PHP.
- Challenges the hypothesis that Gs alpha deficiency is the primary driver of olfactory dysfunction in PHP.