Vitamin D Binding Protein (Gc) Allele Variation Effects Response to Vitamin D Treatment

We have just completed a randomized, clinical trial of 100,000 IU Vitamin D3 given as a single dose at the beginning of winter. We found a wide range of responses to the dose. This study proposes that genetic differences account for some of the variation in response of 25(OH)D levels after treatment with oral Vitamin D.

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Key information

Conditions

Vitamin D Status

Age range

19 year–90 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Creighton University

Omaha, Nebraska, 68131, United States

About this study

We suspect that the wide range of response is effected by other factors such as variation in Vitamin D binding protein (the major transporter of Vitamin D metabolites).

Gc, also known as Vitamin D binding protein (DBP), group specific component, or Gc globulin, is a 52-58 kDa multifunctional plasma protein, synthesized in the liver. The gene encoding for Gc is located on chromosome 4, and three common co-dominant alleles give rise to three phenotypes (Gc1s, Gc1f, and Gc2). Gc binds actin, recruits neutrophil leukocytes and converts into a macrophage- and osteoclast- activating factor. It also is the major transporter of Vitamin D and its' metabolites. Lauridsen et al. showed that Gc phenotype correlates with 25(OH)D levels in a group of postmenopausal women.

This study proposes that Gc phenotype accounts for some of the variation in response of 25(OH)D levels after treatment with oral Vitamin D.

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

Must be willing to participate with an additional blood draw.
Must have been in the previous study.

Exclusion criteria

Will not be eligible if not a part of the previous study

Treatment and study plan

Primary outcomes

Gc concentration and phenotype

Time frame: at 1st visit

Sponsors and collaborators

Lead sponsor

Creighton University

Other

Registry information

Acronym: Gc

Important dates

Study start: 2007
Primary completion: 2008
Study completion: 2008
First posted: Apr 2, 2008
Registry last updated: Apr 2, 2008

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