Why Does Diabetes Affect Some Kidneys More Than Others? Your genes may hold the answer.
If you have diabetes, you've probably been told about the risk of kidney disease. But here's something that surprises many patients: two people with the same type of diabetes, similar blood sugar control, and the same number of years with the condition can have very different outcomes for their kidneys. One might sail through decades with healthy kidney function, while the other develops serious kidney damage. Why? Science increasingly points to your genes.
The Numbers Tell an Important Story
Diabetes is one of the fastest-growing health conditions in the world and a leading cause of kidney failure. But it is not equally devastating for everyone who has it.
This means that the majority of people with diabetes — if well managed — do not develop severe complications. So what separates those who do from those who don't? Blood sugar control matters, of course. But researchers have found something else at work: family history, and ultimately, genetics.
If your sibling has both diabetes and kidney disease, you have approximately 2–4 times the risk of developing kidney disease yourself — compared to someone whose sibling has diabetes but healthy kidneys. This family clustering was one of the first clues that genes play a major role.
What Exactly Are "Diabetes Complications"?
When we talk about complications of diabetes, we're really talking about damage to blood vessels — both large and small — caused by persistently high blood sugar levels over many years. These fall into two broad categories:
What's fascinating — and important — is that these complications don't always occur together. Some people with diabetes develop severe kidney disease but have minimal eye damage. Others develop eye disease without significant kidney involvement. These patterns suggest that different genetic factors may be driving different complications, even within the same person.
How Do Genes Influence Kidney Disease in Diabetes?
Your genes don't cause diabetic kidney disease directly. Rather, they influence how vulnerable your kidneys are to the damage that high blood sugar causes. Think of it like this: if two houses are caught in the same storm, the one built on weaker foundations suffers more damage. High blood sugar is the storm; your genes help determine the foundation.
"Genetics alone didn't cause your kidney disease — but your genes may have made your kidneys more or less resilient to the long-term effects of diabetes."
Scientists have now identified several specific genes that appear to influence kidney disease risk in people with diabetes. One of the most significant recent discoveries involves a gene called COL4A3 — a gene that is part of the scaffolding that holds your kidney's filtering structure together. A common variation in this gene appears to either protect the kidneys from diabetic damage or make them more vulnerable to it.
What Researchers Have Found
A 2019 study examined over 19,000 people with diabetes and identified COL4A3 — a gene involved in the structure of the kidney's filtering membrane — as a significant factor in who develops kidney disease. Interestingly, this protective effect was strongest in people with poor blood sugar control, suggesting the gene becomes especially important when blood sugars run high.
Other genes linked to kidney disease risk in diabetes include those involved in kidney structure (BMP7, DDR1), kidney inflammation (AFF3), and filtering function (UMOD). Each gives scientists — and eventually your doctors — a better map of why some kidneys are more vulnerable than others.
Does This Mean My Fate Is Written in My DNA?
Absolutely not. And this is perhaps the most important message in all of this science. Genes are not destiny — they are tendencies. Having a genetic variant that increases kidney disease risk does not mean you will develop kidney failure. It means your kidneys may need more careful protection.
Here's why this distinction matters in practice: The treatments we have for preventing and slowing diabetic kidney disease are remarkably effective. These include:
- Tight blood sugar control: Strong evidence shows that keeping HbA1c well controlled significantly reduces the risk of kidney complications.
- Blood pressure management: High blood pressure speeds up kidney damage in diabetes. ACE inhibitors and ARBs (common blood pressure medications) have a specific kidney-protective effect.
- SGLT2 inhibitors: A newer class of diabetes medication that has shown remarkable ability to slow kidney disease progression and protect cardiovascular function.
- GLP-1 receptor agonists: Another newer medication class with proven cardiovascular and kidney benefits in people with type 2 diabetes.
- Regular kidney function monitoring: Early detection of rising protein in the urine (albuminuria) or declining eGFR gives your nephrologist the chance to intervene before damage becomes irreversible.
What About Family Members?
Because kidney complications in diabetes run in families, your relatives who have diabetes deserve to know their risk may be higher if you have developed kidney disease. This doesn't mean they should panic — it means they should be especially diligent about:
- Annual urine tests: This simple urine test (UACR) can detect early kidney stress, often years before function declines.
- Regular eGFR blood tests: This measures how well your kidneys are filtering. A trend downward — even within the normal range — is an important signal.
- Proactive discussion with their doctor about kidney-protective medications: Don't wait for problems to appear. Ask about SGLT2 inhibitors and ACE inhibitors.
The Future: Personalised Kidney Care
We are at the beginning of an exciting era in medicine. As genetic research advances, we are moving closer to a world where your doctor can use your genetic profile — alongside your traditional risk factors — to predict your personal risk of kidney complications and tailor your treatment accordingly (called precision medicine).
Questions About Your Kidney Health?
Dr. Roger Smith and the team at Renal Services Limited offer comprehensive nephrology consultations, including kidney risk assessment and personalised management plans for patients with diabetes in Jamaica.