Defining the Physiological Mechanisms of Risk Genes for Hyperglycaemia, Insulin Resistance and Type 2 Diabetes (DIVA - PAM)

University of Oxford

Status: Unknown

Conditions: Type 2 Diabetes

Treatments: Other: Isoglycaemic Clamp; Other: 4 Hour Frequently Sampled Oral Glucose Tolerance Test

Study type: Observational

Funder types: Other

Identifiers

NCT02723110

15/SC/0072

Details and patient eligibility

About

Recent genetic association studies have identified variants in the Peptidyl-Glycine alpha-amidating mono-oxygenase (PAM) gene that increase the risk of diabetes likely through a defect in beta-cell function. This has been followed up and supported by novel kinetic assays and cellular studies. This investigation will recall heterozygous carriers of the risk allele at rs78408340 and age, BMI and gender matched controls from the Oxford Biobank. The study will compare the incretin effect, glucagon-like peptide-1(GLP-1), insulin, glucose levels and PAM protein activity in individuals both with and without the risk variant. The aim of the study is to gain mechanistic insight into the effect of the variant on human physiology and diabetes pathogenesis.

Full description

Note: The study will utilize an adaptive study design with an interim analysis at 40 volunteers (20 v 20) with the possibility of adding an additional 20 volunteers to the study (10 v 10) if the criteria for futility or clear effect are not met.

The criteria are; stop and reject null hypothesis if t > 2.490 and stop and accept null hypothesis if t < 1.033. If the t falls between these values an additional 20 volunteers (10 v10) will be recruited. The decision to stop or additional volunteers will be based on the incretin effect (primary outcome).

Enrollment: 40 estimated patients

Sex: All

Ages: 30 to 65 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Adult, age 30-65 inclusive, healthy, appropriate genotype
• Mental capacity to consent

Exclusion criteria

• Demographics: <30 and >65 years old
• Medical history: Bariatric surgery, surgery on gut/ stomach; history of recent significant weight loss (>10% of weight in last year); known cardiovascular disease
• Medications: Currently prescribed glucose-lowering medication, oral/IV corticosteroid treatment, any medication effecting gastric motility or glucose metabolism

Trial design

40 participants in 2 patient groups

rs78408340 heterozygous carriers

Treatment:

Other: 4 Hour Frequently Sampled Oral Glucose Tolerance Test

Other: Isoglycaemic Clamp

homozygous non-risk allele carriers

Treatment:

Other: 4 Hour Frequently Sampled Oral Glucose Tolerance Test

Other: Isoglycaemic Clamp