Active, Not Recruiting

NCT Number: NCT02692872

Screening for Alpha Thalassemia in Healthy Volunteers

Background:

Alpha thalassemia is a blood disorder. It is caused by genetic deletions. Part of the DNA is missing from a group of genes called alpha globin. Alpha thalassemias are some of the most common genetic deletions. We are testing for alpha thalassemia trait. Alpha thalassemia trait is when someone has only two out of the normal four alpha globin genes. In some people, they lead to no symptoms. Others have changes that lead to disease, including mild anemia. Researchers want to learn more about alpha thalassemia and blood vessels. This may allow them to develop new treatments for blood diseases such as sickle cell disease.

Objective:

To better understand how alpha globin deletions in healthy people affect blood vessels.

Eligibility:

Healthy volunteers ages 18-39 who self-report African ancestry.

Design:

Participants will provide a one-time saliva sample. This can be by mail, in-person at a study event, or at NIH.

Participants will get a small kit to collect their saliva sample. The kit has easy instructions. The sample does not need to be put in the refrigerator.

Participants will spit a small amount of saliva (less than half a teaspoon) into a collection tube.

Participants will close the funnel lid tightly, and then unscrew the funnel lid from the tube. They will then close the tube tightly with the small cap provided and shake the tube for 5 seconds.

Participants will place the tube in the provided envelope and mail it to NIH. The specimen will be stored and processed in the lab.

Participants may be invited to participate in more research studies, whether or not researchers find that they have alpha thalassemia trait.

Active, Not Recruiting

This study is active but is not currently recruiting participants.

Notify Me

Key information

Conditions

Alpha Thalassemia Anemia Anemia, Hemolytic Anemia, Hemolytic, Congenital Congenital, Hereditary, and Neonatal Diseases and Abnormalities Genetic Diseases, Inborn Hematologic Diseases Hemic and Lymphatic Diseases Hemoglobinopathies Thalassemia alpha-Thalassemia

Age range

18 year–39 year

Sex eligibility

All sexes

Study type

Observational

Primary location

National Institutes of Health Clinical Center

Bethesda, Maryland, 20892, United States

About this study

Many of the complications of sickle cell disease, such as stroke, kidney damage, skin ulceration,pulmonary hypertension, and cardiac hypertrophy are prevented, delayed or reduced by inheritance of one of more deletions of the alpha globin genes. Our long-term research goal is to understand how deletions of alpha globin protect against the vascular complications of sickle cell disease.

Deletions of alpha globin are common and found in approximately 5% of the world s population.They are especially common among Africans and people of African ancestry, as well as in India, China, and the Pacific Islands, where prevalence can range from 5 - 80%. A single deletion has little effect on the red blood cell, but two deletions can give rise to alpha thalassemia, a mild microcytic anemia. Patients with sickle cell disease who have two alpha globin deletions tend to have a higher hemoglobin level, smaller red blood cells, and a lower fraction of circulating reticulocytes - consistent with decreased hemolysis and red cell turnover. They also have a lower number of dense or irreversibly sickled cells. These changes might explain why alpha globin deletions reduce the severity of sickle cell disease.

However, a novel function for alpha globin as a regulator of endothelial nitric oxide (NO) has recently been identified that raises new questions about how alpha globin deletions protect against sickle cell disease. We hypothesize that individuals with two alpha globin deletions will have decreased gene expression and protein levels of alpha globin in vascular endothelium, permitting more NO to diffuse across the myoendothelial junction, compared to individuals who have all four alpha globin genes intact. In this protocol we will screen healthy volunteers to identify those with two alpha globin deletions; these individuals as well as matched controls will be referred to a separate protocol to undergo studies of vascular endothelial function.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

INCLUSION CRITERIA:

Subject report of the following:

Age 18 - 39
Self-report of African ancestry
Willingness and legal ability to give and sign informed study consent

Exclusion criteria

There are no exclusion criteria for this screening protocol

Treatment and study plan

Primary outcomes

Identify Presence of Double Alpha Globin Deletions in Healthy Volunteers.

Time frame: Ongoing

As this is not a treatment protocol, there is no primary endpoint. The primary objective is to identify presence of double alpha globin deletions in healthy volunteers.

Sponsors and collaborators

Lead sponsor

National Institute of Allergy and Infectious Diseases (NIAID)

Nih

Registry information

Official study title

Screening for Alpha Globin Deletions

Important dates

Study start: 2017
Primary completion: 2027
Study completion: 2027
First posted: Feb 26, 2016
Registry last updated: Apr 24, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Published trials that share one or more normalized conditions with this study.

Completed