The INS gene provides instructions for producing the hormone insulin, which is necessary for the control of glucose levels in the blood. Glucose is a simple sugar and the primary energy source for most cells in the body.
Insulin is produced in a precursor form called proinsulin, which consists of a single chain of protein building blocks (amino acids). The proinsulin chain is cut (cleaved) to form individual pieces called the A and B chains, which are joined together by connections called disulfide bonds to form insulin.
At least 10 mutations in the INS gene have been identified in people with permanent neonatal diabetes mellitus. Individuals with this condition often have a low birth weight and develop increased blood sugar (hyperglycemia) within the first 6 months of life.
INS gene mutations that cause permanent neonatal diabetes mellitus change single protein building blocks (amino acids) in the protein sequence. These mutations are believed to disrupt the cleavage of the proinsulin chain or the binding of the A and B chains to form insulin, leading to impaired blood sugar control.
Genetics Home Reference provides information about type 1 diabetes.
Mutations in the INS gene can also cause other disorders involving insulin production and blood sugar control. Some individuals with INS gene mutations have increased levels of proinsulin in their blood (hyperproinsulinemia) and may also have impaired blood sugar control. INS gene mutations are also associated with a disorder called maturity-onset diabetes of the young (MODY). This term refers to hereditary forms of relatively mild diabetes mellitus caused by changes in single genes.
- insulin preproprotein