Leptin is a hormone produced by the fat cells that researchers have shown to play a role in
controlling appetite. Certain people with severe insulin resistance have little or no leptin.
The purpose of this study is to investigate people whose leptin levels have been found to be
lower than 85 percent of the general population. Researchers will determine whether insulin
levels in these participants improve when they are treated with genetically engineered
Study participants must be age 8 years or older and must have severe insulin resistance
syndrome and leptin deficiency. During an initial 7-day visit to the Clinical Center,
researchers will evaluate participants' metabolic parameters, such as insulin responsiveness,
lipid levels, appetite, and hormone levels. After taking these tests, participants will
self-inject doses of leptin once or twice a day and will be monitored for treatment outcomes
as well as side effects via follow-up visits. These inpatient follow-up visits will involve
both blood tests and imaging studies at the Clinical Center at 4, 8, and 12 months after the
initial visit, and every 6 months thereafter.
Hypoglycemia is the term used to refer to lower than normal levels of blood sugar. This study
will continue to research the causes of hypoglycemia.
Patients involved in the study will be admitted to the Clinical Center of the National
Institutes of Health and undergo tests for evaluating blood sugar. Patients will be required
to refrain from eating for a set period of time and will undergo blood tests for insulin
levels and several other specific diagnostic tests related to insulin secretion. The patients
will be under supervision and will be provided with appropriate medical and surgical
attention as needed.
The study will allow researchers to obtain blood, plasma, DNA, and RNA for genetic studies of
insulin. There will be a focus on the causes of insulin resistance and diabetes mellitus.
Insulin is a hormone found in the body that controls the level of sugar in the blood. Insulin
resistance refers to conditions like diabetes when insulin does not work properly. In this
study researchers would like to compare patients with diabetes and other forms of insulin
resistance to normal individuals. The study will investigate how insulin attaches to cells.
Researchers will take 4 to 6 ounces (100-150 ml) of blood from adult patients and may request
up to 12 ounces (one unit) of blood if necessary. Skin samples may be taken for a biopsy if
further genetic testing is necessary. In addition some patients may be asked not to eat for
up to 72 hours prior to testing.