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HNF1A gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

HNF1A gene

The HNF1A gene encodes a transcription factor that regulates gene activity, playing a critical role in the development and function of the pancreas and liver.

Normal Function

The HNF1A gene provides instructions for making a protein called hepatocyte nuclear factor-1 alpha (HNF-1α). The HNF-1α protein acts as a transcription factor, which means it attaches (binds) to specific regions of DNA and helps control the activity of certain genes. While this protein is found in several tissues and organs, it seems to be especially important in the pancreas and liver.

Regulation of gene activity by the HNF-1α protein is critical for the growth and development of beta cells in the pancreas. Beta cells produce and release (secrete) the hormone insulin. Insulin helps regulate blood sugar levels by controlling how much sugar (in the form of glucose) is passed from the bloodstream into cells to be used as energy. The HNF-1α protein also controls genes involved in liver development. By controlling genes that regulate cell growth and survival, the HNF-1α protein is thought to act as a tumor suppressor, helping prevent cells from growing and dividing too rapidly.

Health Conditions Related to Genetic Changes

Maturity-onset diabetes of the young

Mutations in the HNF1A gene cause maturity-onset diabetes of the young (MODY), a group of conditions characterized by abnormally high blood glucose levels that usually begin before age 30. HNF1A gene mutations cause the most common type of MODY, called HNF1A-MODY (also known as MODY3).

HNF1A gene mutations that cause HNF1A-MODY occur in one of the two copies of the gene in each cell. These mutations result in the production of an altered HNF-1α protein that is unable to function normally. This interrupts transcription, impairing beta cell development and function. As a result, the cells are less able to produce insulin in response to glucose, leading to elevated blood glucose levels.

Other disorders

Rarely, individuals with HNF1A-MODY develop noncancerous liver tumors called hepatocellular adenomas due to a non-inherited somatic mutation in the second copy of the HNF1A gene. Hepatocellular adenomas can also occur in people without HNF1A-MODY if they have somatic mutations in both copies of the HNF1A gene. These mutations severely reduce or eliminate the function of the HNF-1α protein in affected liver cells, causing them to grow uncontrollably.

Other Names for This Gene

  • HNF1 Homeobox A Gene
  • LFB1
  • TCF1

Genomic Location

The HNF1A gene is found on chromosome 12.

Frequently Asked Questions

Symptoms of HNF1A-MODY are similar to other forms of diabetes, including increased thirst, frequent urination, unexplained weight loss, and fatigue. However, the onset is usually before age 30, and often the symptoms are milder, leading to a diagnosis during routine blood tests or pregnancy. A key indicator is a strong family history of diabetes that doesn't fit the typical Type 1 or Type 2 patterns.
HNF1A-MODY often responds very well to low doses of sulfonylurea medications, which stimulate the pancreas to produce more insulin. Unlike Type 2 diabetes, insulin therapy is often not needed initially and can sometimes be avoided for many years. Lifestyle modifications, including a healthy diet and regular exercise, are also important but typically less impactful than medication for blood sugar control.
HNF1A-MODY is inherited in an autosomal dominant pattern. This means that if a parent has the HNF1A gene mutation, there is a 50% chance that each of their children will inherit the mutation and develop the condition. Genetic counseling can help families understand these risks and discuss testing options.
HNF1A-MODY is distinct because it's caused by a single gene mutation, typically presenting before age 30, and is inherited in an autosomal dominant pattern. Unlike Type 1 diabetes, it's not an autoimmune condition, and unlike Type 2, it's not primarily linked to obesity or insulin resistance, though these can sometimes coexist. Individuals with HNF1A-MODY often have a strong family history of early-onset diabetes and are usually very sensitive to sulfonylurea medications, which can effectively manage their blood sugar.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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