This study will explore the genetics of taste and taste deficits. The sense of taste plays a crucial role in food choices, allowing people to identify beneficial foods (those with high caloric value, which are typically sweet) and foods likely to be toxic (usually bitter substances). The loss of sense of taste in older people plays a role in decreased appetite and poor nutrition. Taste deficits may adversely affect people in ways that are not well understood. This study will examine why some people (about one-fourth of all people in the United States) cannot taste a substance called phenylthiocarbamide (PTC). The inability to taste PTC is due to inherited factors that are not yet clear.

Individuals age 18 and older who can taste PTC and individuals who cannot taste PTC may be eligible for this study. Participants will taste a number of liquid solutions until they find one with a clear taste. Then they will taste another group of solutions and decide which ones have that taste and which have no taste. Finally, they will taste a third group of solutions until they find one with a different taste. About 2 tablespoons of blood will be drawn from participants for genetic tests related to the sense of taste.

Condition
Taste Disorder Healthy

The primary goal of this study is to identify the underlying cause of deficits in the ability to taste bitter substances, using the compound phenylthiocarbamide (PTC) as a model. Individuals will be tested to identify those who can and cannot taste PTC. Individuals will have 20 cc of blood drawn to obtain DNA. These DNA samples will then be analyzed for variation in genes whose products are known to be involved in bitter taste perception pathways. Information about individuals' DNA sequence variation will then be correlated with their PTC taste phenotype to identify the specific genetic variation that causes phenotypic variation, providing molecular structure-function information in the bitter sensory pathway.

Genders Eligible for Study:  Both

Accepts Healthy Volunteers

Criteria

INCLUSION CRITERIA:
This study includes individuals age 18 or older.
This study includes both males and females, and includes members of all racial and ethnic groups.
This study includes both individuals with a normal sense of taste, and those unable to taste PTC.
EXCLUSION CRITERIA:
Individuals excluded will be those under age 18, those who are cognitively impaired, those with a physical impairments in swallowing, those who have general impairments in the sense of taste, those currently using psychoactive medications, prisoners, or other at-risk populations.

Maryland
      National Institute on Deafness and Other Communication Disorders (NIDCD), 9000 Rockville Pike,  Bethesda,  Maryland,  20892,  United States; Recruiting

Study ID Numbers:  010230; 01-DC-0230
Record last reviewed:  August 11, 2004
Last Updated:  August 11, 2004
Record first received:  August 17, 2001
ClinicalTrials.gov Identifier:  NCT00022997
Health Authority: United States: Federal Government
ClinicalTrials.gov processed this record on 2004-11-08