This site became the new on June 19th. Learn more.
Show more Menu IMPORTANT: Listing of a study on this site does not reflect endorsement by the National Institutes of Health. Talk with a trusted healthcare professional before volunteering for a study. Read more... Menu IMPORTANT: Talk with a trusted healthcare professional before volunteering for a study. Read more... Menu
Give us feedback

Mechanisms of Low Levels of Apolipoprotein B

This study has been completed.
Information provided by:
National Heart, Lung, and Blood Institute (NHLBI) Identifier:
First received: May 25, 2000
Last updated: July 28, 2016
Last verified: January 2008
To determine mechanisms of low levels of apolipoprotein B.

Cardiovascular Diseases Heart Diseases Hypobetalipoproteinemia

Study Type: Observational

Resource links provided by NLM:

Further study details as provided by National Heart, Lung, and Blood Institute (NHLBI):

Study Start Date: August 1997
Study Completion Date: June 2002
Primary Completion Date: June 2002 (Final data collection date for primary outcome measure)
Detailed Description:


Elevated apoB levels are associated with an increased risk of coronary heart disease. Hypobetalipoproteinemia (HBLP) is characterized by apoB levels less than the 5 percentile. Dr. Welty, the principal investigator, sequenced mutations for truncated forms of apoB-67, apoB-55 and apoB-44.4 which causes HBLP, described a kindred from the Framingham Heart Study with HBLP due to an unidentified apoB gene mutation and purified apoB-67 containing lipoprotein particles. Heterozygous apoB-67 subjects have one normal allele making apoB-100; therefore, apoB levels would be predicted to be at least 50 percent of normal; however, they are 24 percent of normal. Dr. Welty has shown that these lower than expected levels result from decreased production of VLDL apoB-100, LDL apoB-100 and apoB-67, increased catabolism of VLDL apoB-100, and increased direct removal of apoB-67 from VLDL.


The first aim is to locate the apoB gene mutation in the Framingham kindred. The second aim is to perform stable isotope studies in the apoB-55 and apoB-44.4 kindreds to determine if apoB metabolism for these shorter truncations is similar to that for apoB-67. In aim three, apoB-100 synthesis is studied in heterozygous apoB-70 transgenic mice. If it is 25-25 percent of normal litter mates, the mechanism for this reduction in apoB-100 levels will be studied in hepatocytes isolated from the transgenic mice. In specific aim 4, size and composition of VLDL are compared in apoB-67 subjects and controls to determine if larger size or compositional changes account for the faster catabolism of VLDL apoB-100. The study has been extended through June 2007.


Ages Eligible for Study:   up to 100 Years   (Child, Adult, Senior)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   No
No eligibility criteria
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT00005565

Sponsors and Collaborators
National Heart, Lung, and Blood Institute (NHLBI)
OverallOfficial: Francine Welty Beth Israel Deaconess Medical Center
  More Information

Publications: Identifier: NCT00005565     History of Changes
Other Study ID Numbers: 5114
R01HL056895 ( U.S. NIH Grant/Contract )
Study First Received: May 25, 2000
Last Updated: July 28, 2016

Additional relevant MeSH terms:
Cardiovascular Diseases
Heart Diseases
Lipid Metabolism, Inborn Errors
Metabolism, Inborn Errors
Genetic Diseases, Inborn
Lipid Metabolism Disorders
Metabolic Diseases processed this record on September 21, 2017