The Effect of ß-cell Specific Glucokinase Mutation on Glucose Homeostasis and Insulin Secretion in a MODY-2 Family

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details. Identifier: NCT01960231
Recruitment Status : Recruiting
First Posted : October 10, 2013
Last Update Posted : June 20, 2017
Information provided by (Responsible Party):
Sheba Medical Center

Brief Summary:

Type 2 diabetes mellitus patients exhibit many glucose homeostasis abnormalities in different tissues and organs. Among the more important defects are disturbed hepatic glucose metabolism and defective pancreatic β-cell function. Hexokinase IV, commonly known as glucokinase, is the predominant hexokinase expressed in the liver, the pancreatic β-cells (where it functions as the glucose sensor for insulin secretion) and in glucose-sensory cells in the hypothalamus and gut.

The glucokinase gene contains two distinct promoters. The downstream one is active only in hepatocytes and the upstream promoter is active only in extrahepatic glucose sensory-cells. Alternative promoters enable differential regulation of gene transcription in liver and extrahepatic sites. In pancreatic β-cells, glucokinase expression at the mRNA level is largely constitutive, whereas in the liver it undergoes large adaptive changes in response to nutritional states, enabling larger changes in glucokinase activity than would otherwise be possible by post-transcriptional regulation alone.

Most of the MODY-2 patients were found to have glucokinase mutations located in areas that are common to the liver and pancreas. The diabetes in these patients is related both to defect in insulin secretion and abnormal hepatic glucose metabolism. Point mutation in the pancreatic specific promoter was recently described as a cause for impaired fasting glucose [Diabetes 58:1929-1935, 2009]. The investigator have recently identified a MODY-2 family with a genetic defect that is located in the pancreatic promoter, sparing the liver promoter. This family demonstrates that abnormal insulin secretion alone (perhaps together with other extrahepatic glucose sensors) is enough to cause diabetes.

In this study, the investigators would like to use an oral glucose tolerance test (OGTT) and continuous glucose monitoring (CGM) technique in order to elucidate the relative roll of the hepatic glucokinase in normal glucose homeostasis. This issue is complicated by the fact that in addition to glucokinase, hexokinase isoenzymes I, II and III are also expressed at very low levels in hepatocytes. They are an important back-up mechanism when glucokinase activity is compromised, as in liver cirrhosis or murine models with liver-specific glucokinase knock-down. However, impaired hepatic glycogen synthesis was demonstrated in MODY-2 subjects (JCI 1996:98:1755). By comparing members of the investigators MODY-2 family with members of other MODY-2 families and normal controls the investigators hope to shade some light on this question.

Condition or disease Intervention/treatment
MODY-2 Diabetes Other: OGTT

Study Type : Observational
Estimated Enrollment : 30 participants
Observational Model: Other
Time Perspective: Prospective
Study Start Date : October 2013
Estimated Primary Completion Date : December 2017
Estimated Study Completion Date : December 2017

Group/Cohort Intervention/treatment
pancreas specific MODY-2 Other: OGTT

Primary Outcome Measures :
  1. fasting and post glucose load glucose level [ Time Frame: 1 year ]

Secondary Outcome Measures :
  1. fasting and post glucose load Insulin [ Time Frame: 1 year ]
  2. fasting and post glucose load c-peptide [ Time Frame: 1 year ]

Other Outcome Measures:
  1. glucose metabolism measured by CGMS [ Time Frame: 1 year ]

Information from the National Library of Medicine

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Ages Eligible for Study:   12 Years to 80 Years   (Child, Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population
MODY-2 family

Inclusion Criteria:

  1. MODY 2 patients with documented mutations in the glucokinase promoter or coding region.
  2. Healthy non-diabetic individuals matched for age, sex and BMI with recruited MODY2 patients.
  3. Age range - 12-80; males and females

Exclusion Criteria:

  1. Unable to provide written informed consent.
  2. Unable to safely stop glycemia related medications for the duration of the test + wash-out period.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01960231

Contact: Jacob Ilany, MD 972-3-5302021

Sheba Medical Center Recruiting
ramat Gan, Israel, 52621
Contact: Ayana Paster, RD    972-3-5302021      
Sponsors and Collaborators
Sheba Medical Center
Principal Investigator: Jacob Ilany, MD Sheba Medical Center

Responsible Party: Sheba Medical Center Identifier: NCT01960231     History of Changes
Other Study ID Numbers: SHEBA-13-0464-JI-CTIL
First Posted: October 10, 2013    Key Record Dates
Last Update Posted: June 20, 2017
Last Verified: June 2017