NIH Clinical Research Studies

Protocol Number: 97-DC-0057

Active Accrual, Protocols Recruiting New Patients

Non-Parametric and Parametric Linkage Studies of Stuttering
Stuttering is an abnormality in speech that affects the rhythm of speech. People who stutter know what they wish to say, but at the time are unable to say it because of involuntary repetition, unnecessary lengthening (prolongation), or early stopping (cessation). Stuttering is characterized by repetitions or prolongation of the first syllable, or silent prolongations, sometimes known as blocks.

Researcher intend on studying the genetic basis for stuttering. The goal of the study is to find the genes that help cause stuttering and determine regions of the human genetic make-up (genome) that are linked to stuttering.. To do this researchers will study the patterns of inheritance in families who have had members who stutter.

The study has two objectives. The first objective is to develop a large collection of DNA samples from individuals in stuttering families, that will include both members that stutter and who do not stutter.

The second objective of the study will be to find out the basic combination of genes (genotype) making up all of the participants DNA. Once this is completed researchers hope to map out and find areas or regions of DNA that are linked to stuttering.

Genetic linkage is the initial step in positional cloning, and the cloning of genes which predispose individuals to stuttering is a long term goal of this research study.

Sponsoring Institute:
National Institute on Deafness and Other Communication Disorders (NIDCD)
Recruitment Detail
Type: Participants currently recruited/enrolled
Gender: Male & Female
Referral Letter Required: No
Population Exclusion(s): None

Eligibility Criteria:

This study includes literate individuals 8 years of age and over.

This study also requires stuttering that persists for a period of 6 months or more, which is taken as a standard minimum period that defines stuttering.

This study includes both males and females, although families with affected females are specifically solicited, since females are less afflicted with this disorder in adulthood.

This study includes all racial and ethnic groups, and will specifically seek stutterers from genetically isolated populations (e.g. Ethnic Israeli, West Africa), since these may provide increased power to detect linkage and subsequently narrow the position of the genes involved.


Families in which affected family members (beyond the proband) stuttered only as children.

Families with no clearly affected individuals beyond the proband.

Cognitively impaired individuals, in the instances that their impairment prevents understanding and free decision-making regarding the Informed Consent.

Individuals who developed stuttering following trauma to the central nervous system.

Individuals with chronic medical conditions that prevent clear evaluation of stuttering, including stroke, dementia, and degenerative neurological disease.

Illiterate Individuals.

Special Instructions:
Currently Not Provided
DNA Samples
Buccal Swab
Statistical Analysis
Recruitment Keyword(s):
Investigational Drug(s):
Investigational Device(s):
Supporting Site:
National Institute on Deafness and Other Communication Disorders

Patient Recruitment and Public Liaison Office
Building 61
10 Cloister Court
Bethesda, Maryland 20892-4754
Toll Free: 1-800-411-1222
TTY: 301-594-9774 (local),1-866-411-1010 (toll free)
Fax: 301-480-9793


Vertical transmission of susceptibility to stuttering with sex-modified expression

Genetic factors in stuttering confirmed

Concordance for stuttering in monozygotic and dizygotic twin pairs

Active Accrual, Protocols Recruiting New Patients

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