Genetics and Diabetes Transplants: What You Need to Know

Diabetes is often described as a condition involving high blood sugar, but the full story is much more complex.

Our genes can influence whether we develop diabetes, how the condition affects the body and, in some cases, which treatment may work best.

At the same time, medical advances are making it possible to replace damaged insulin-producing cells through pancreas, islet-cell and stem-cell transplantation.

These treatments are not suitable for everyone, and they are not yet a simple cure. However, they are helping researchers move closer to restoring the body’s natural ability to produce insulin.

How Does Genetics Affect Diabetes?

Genes are the biological instructions we inherit from our parents.

They influence many aspects of our bodies, including how we process glucose, produce insulin and regulate the immune system.

However, the role of genetics is not the same in every type of diabetes.

Type 1 Diabetes

Type 1 diabetes is an autoimmune condition.

This means the immune system mistakenly attacks the beta cells in the pancreas that produce insulin.

A person can inherit genes that increase the risk of developing type 1 diabetes.

Some of the most important are called HLA genes. These genes help the immune system distinguish between the body’s own cells and foreign substances.

Certain HLA patterns increase the risk of type 1 diabetes, while others may offer some protection.

However, having a high-risk genetic pattern does not mean that someone will definitely develop the condition.

Other factors are also involved. These may include environmental exposures, infections, immune-system changes and other biological events that researchers are still studying.

In other words, type 1 diabetes is not usually inherited through one faulty gene.

It develops through a combination of genetic susceptibility and other triggers.

Type 2 Diabetes

Type 2 diabetes also has a strong genetic component.

People with a parent or close relative who has type 2 diabetes are generally more likely to develop it themselves.

However, type 2 diabetes is not caused by one gene alone.

Scientists have identified hundreds of areas in the human genome that may influence the risk of type 2 diabetes.

These genetic differences can affect:

• how well the pancreas produces insulin;
• how sensitive the body is to insulin;
• where the body stores fat;
• how the liver processes glucose; and
• how appetite and metabolism are regulated.

A large international study involving more than 2.5 million people identified 1,289 genetic signals associated with type 2 diabetes.

This shows that two people with the same diagnosis may develop diabetes through very different biological pathways.

Lifestyle and environmental factors remain important.

Physical activity, diet, age, body weight, sleep, medication and social circumstances can all interact with genetic risk.

Having a family history of type 2 diabetes therefore increases risk, but it does not make the condition unavoidable.

When Is Diabetes Caused by a Single Gene?

Some rare forms of diabetes are caused mainly by a change in one gene.

These are known as monogenic diabetes.

The two main forms are:

• maturity-onset diabetes of the young, usually called MODY; and
• neonatal diabetes, which develops very early in life.

Monogenic diabetes may account for approximately 1% to 5% of all diabetes cases, depending on the population and how actively people are tested.

It is often mistaken for type 1 or type 2 diabetes because the symptoms can be similar.

Doctors may consider genetic testing when diabetes:

• develops before six months of age;
• develops at a young age without the usual signs of type 1 diabetes;
• affects several generations of the same family;
• occurs without typical type 1 diabetes antibodies; or
• develops in someone who does not show strong signs of insulin resistance.

An accurate genetic diagnosis can make a major difference.

Some people with monogenic diabetes can move from insulin injections to tablets called sulfonylureas.

Others may need insulin or monitoring for related kidney, liver or developmental conditions.

Genetic testing may also help relatives understand whether they are at risk.

Why Would Someone Need a Diabetes Transplant?

In type 1 diabetes, the body has destroyed most of its insulin-producing beta cells.

Insulin injections and insulin pumps replace the missing insulin, while continuous glucose monitors help people track their glucose levels.

These technologies can be highly effective, but they do not fully reproduce the way a healthy pancreas works.

A healthy pancreas constantly adjusts insulin production.

It releases more insulin when blood glucose rises and reduces insulin production when glucose falls.

Transplantation attempts to restore this natural process by providing working pancreatic tissue or replacement beta cells.

The aim is not to transplant diabetes from one person to another.

The aim is to replace the cells or organ that can no longer produce enough insulin.

Whole-Pancreas Transplantation

A pancreas transplant involves surgically placing a healthy donor pancreas into the recipient’s body.

The person’s original pancreas is usually left in place because it still performs other important digestive functions.

Pancreas transplantation is most commonly considered for people with type 1 diabetes who also need a kidney transplant because of severe kidney damage.

It may also be considered for a small number of people who experience repeated, life-threatening episodes of low blood sugar despite receiving the best available diabetes treatment.

A successful transplant can allow the body to produce insulin again.

Some recipients may no longer need insulin injections while the transplanted pancreas continues to function.

However, this is major surgery.

Possible risks include:

• bleeding;
• infection;
• blood clots;
• inflammation of the transplanted pancreas;
• rejection of the new organ; and
• failure of the transplant.

Recipients also need long-term medication to suppress their immune systems.

These medicines help prevent rejection, but they can increase the risks of infection, kidney damage and certain cancers.

For this reason, a pancreas transplant is normally reserved for people whose medical need is serious enough to justify the risks.

Islet-Cell Transplantation

Islet-cell transplantation is less invasive than transplanting an entire pancreas.

Islets are small groups of cells found inside the pancreas.

They include the beta cells that produce insulin.

During an islet transplant, doctors isolate these cells from a deceased donor pancreas.

The cells are then infused into a large blood vessel leading to the liver.

The transplanted cells settle in the liver and may begin producing insulin.

This treatment is mainly considered for adults with type 1 diabetes who experience:

• repeated severe episodes of low blood sugar;
• an inability to recognise when their glucose is becoming dangerously low; or
• highly unstable glucose levels despite specialist treatment.

In 2023, the United States Food and Drug Administration approved the first donor-derived pancreatic islet-cell therapy for selected adults with type 1 diabetes.

Some recipients become insulin-independent, while others still need insulin but experience fewer severe glucose emergencies.

In one study of carefully selected transplant recipients, 95% remained free from severe hypoglycaemic events five years after their final islet infusion.

Just over half were insulin-independent at that stage.

These results are encouraging, but they do not mean that every recipient will have the same outcome.

What Is an Islet Auto transplant?

An islet auto-transplant uses a person’s own cells rather than cells from a donor.

This procedure may be performed when someone needs to have their pancreas removed because of severe chronic pancreatitis or another pancreatic condition.

Doctors remove islet cells from the person’s pancreas and place them into the liver.

Because the cells come from the patient’s own body, anti-rejection medication is usually unnecessary.

This procedure is generally not an option for someone with established type 1 diabetes because the immune system has already destroyed most of that person’s insulin-producing cells.

Why Does the Immune System Reject Transplanted Cells?

The immune system is designed to identify and destroy substances that appear foreign.

Transplanted organs and cells carry biological markers from the donor.

The recipient’s immune system may recognise these markers as foreign and attack the transplant.

People with type 1 diabetes face an additional problem.

The autoimmune response that destroyed their original beta cells may also attack the replacement cells.

A transplant may therefore face two separate threats:

1. The immune system may reject the cells because they came from another person.
2. The original diabetes-related autoimmune process may attack the new beta cells.

Immunosuppressive medicines can reduce these reactions, but they also weaken the body’s ability to fight infections and abnormal cells.

Solving this immune problem is one of the biggest challenges in diabetes-transplant research.

Could Stem Cells Provide an Unlimited Supply?

Donor organs and donor islet cells are in very short supply.

Stem-cell technology may offer a possible solution.

Stem cells can develop into different types of specialised cells.

Researchers have learned how to guide certain stem cells into becoming insulin-producing pancreatic cells.

These laboratory-grown cells could potentially provide a renewable and standardised supply of transplant material.

Early human studies have produced promising results.

In a clinical study published in 2025, 14 people with type 1 diabetes received stem-cell-derived islet cells.

All showed signs that the transplanted cells were producing insulin.

Among the 12 people who received the full treatment dose:

• all avoided severe hypoglycaemic events during the reported period;
• all had an HbA1c level below 7%; and
• 10 became insulin-independent after one year.

Although these results are encouraging, the study was small.

Participants still needed immune-suppressing medication, and longer follow-up is required.

Researchers have also produced insulin-making cells from a patient’s own reprogrammed cells.

In 2024, doctors reported that a woman with type 1 diabetes began producing insulin after receiving laboratory-grown islet cells made from her own cells.

This was an important scientific development, but it involved only one patient.

It should not yet be viewed as a proven or widely available treatment.

Can Gene Editing Prevent Rejection?

Gene editing may help scientists create cells that are less visible to the immune system.

Researchers are experimenting with changing genes that control immune recognition.

The goal is to produce insulin-making cells that can survive in the body without requiring lifelong immunosuppressive medication.

In an early human study, researchers transplanted genetically modified donor islet cells into a man with type 1 diabetes without using standard anti-rejection medication.

The cells continued to show signs of function during follow-up, and researchers did not detect the expected immune attack against them.

However, this was a small, early proof-of-concept experiment.

The cell dose was not intended to make the patient completely insulin-independent.

Gene-edited cells also raise important safety questions.

Cells that are hidden too effectively from the immune system might be more difficult for the body to destroy if they become infected or develop abnormal growth.

Researchers will therefore need reliable safety mechanisms and long-term monitoring.

Is Transplantation a Cure for Diabetes?

It is more accurate to describe transplantation as a possible form of beta-cell replacement rather than a permanent cure.

A successful pancreas or islet transplant can restore insulin production and greatly improve glucose control.

Some people may stop using insulin for a period of time.

However:

• the transplanted cells may eventually stop working;
• the immune system may reject the transplant;
• autoimmune diabetes may return;
• immunosuppressive treatment may cause serious side effects; and
• the procedure may not work equally well for everyone.

Most people with type 1 diabetes will continue to use insulin, glucose monitoring and automated insulin-delivery technology rather than transplantation.

At present, transplantation is mainly considered when severe diabetes complications outweigh the risks of the procedure.

The Main Challenges Still Facing Researchers

Before cell replacement can become a routine treatment, researchers need to overcome several major obstacles.

Donor Shortages

There are not enough donor pancreases to treat everyone who could potentially benefit.

Immune Rejection

Cells from another person are normally attacked by the recipient’s immune system.

Recurrent Autoimmunity

The immune response responsible for type 1 diabetes may attack replacement beta cells as well.

Side Effects of Immunosuppression

Anti-rejection drugs can increase the risks of infection, kidney problems and cancer.

Limited Graft Lifespan

Transplanted cells do not always continue functioning permanently.

Manufacturing and Safety

Laboratory-grown cells must be produced consistently and must not contain immature cells that could grow uncontrollably.

Cost and Availability

Transplantation requires highly specialised medical teams, facilities and long-term monitoring.

Fair Access

New treatments must be tested in people from diverse genetic and ethnic backgrounds and should not be limited only to wealthy countries or patients.

What Does the Future Look Like?

The long-term goal is clear.

Scientists want to create a safe and reliable supply of insulin-producing cells that can survive in the body without lifelong anti-rejection medication.

Achieving this would transform type 1 diabetes care.

Stem-cell-derived islets, gene-edited cells, immune-protective capsules and personalised cell therapies are all being investigated.

The progress is real, but it is important not to overstate it.

Most of these treatments are still being tested in small clinical studies.

Researchers need to establish whether they remain safe and effective for many years and across larger groups of patients.

Final Thoughts

Genetics is helping doctors understand why diabetes develops differently from one person to another.

In type 1 diabetes, genes influence the risk of an autoimmune attack.

In type 2 diabetes, many genetic differences affect insulin production, insulin resistance and metabolism.

In monogenic diabetes, a change in a single gene may directly determine the diagnosis and treatment.

Transplantation offers a way to replace the cells that diabetes has damaged or destroyed.

Whole-pancreas and islet-cell transplantation can already help carefully selected patients, while stem cells and gene editing are opening new possibilities.

These developments do not yet provide a simple, permanent cure.

Nevertheless, they represent meaningful progress towards restoring the body’s own ability to control blood glucose.

References

1. American Diabetes Association Professional Practice Committee. Diagnosis and Classification of Diabetes: Standards of Care in Diabetes—2026. Diabetes Care. 2026;49(Suppl. 1).
2. American Diabetes Association Professional Practice Committee. Pharmacologic Approaches to Glycemic Treatment: Standards of Care in Diabetes—2026. Diabetes Care. 2026;49(Suppl. 1).
3. Suzuki K, Hatzikotoulas K, Southam L, et al. Genetic drivers of heterogeneity in type 2 diabetes pathophysiology. Nature. 2024;627:347–357.
4. National Institute of Diabetes and Digestive and Kidney Diseases. Monogenic Diabetes: MODY and Neonatal Diabetes Mellitus. Reviewed August 2024.
5. National Institute of Diabetes and Digestive and Kidney Diseases. Pancreatic Islet Transplantation.
6. United States Food and Drug Administration. FDA Approves First Cellular Therapy to Treat Patients with Type 1 Diabetes. Published 28 June 2023.
7. Hering BJ, Clarke WR, Bridges ND, et al. Factors associated with favourable five-year outcomes in islet-transplant-alone recipients with type 1 diabetes complicated by severe hypoglycaemia. Diabetologia. 2023;66:163–173.
8. Reichman TW, Mascia M, Melton D, et al. Stem-cell-derived, fully differentiated islets for type 1 diabetes. New England Journal of Medicine. 2025.
9. Wang S, Du Y, Zhang B, et al. Transplantation of chemically induced pluripotent stem-cell-derived islets in a patient with type 1 diabetes. Cell. 2024.
10. Carlsson PO, Hu X, Scholz H, et al. Survival of transplanted allogeneic beta cells with no immunosuppression. New England Journal of Medicine. 2025.

This article is provided for general educational purposes and is not a substitute for medical advice, diagnosis or treatment from a qualified healthcare professional.