A new type of diabetes has been found by scientists, and it doesn't show the typical symptoms of Type 1 or Type 2

A newly recognised form of diabetes, called Type 5, was announced this week at the World Congress of Diabetes 2025. A global task force will investigate this less-understood condition, which differs from Type 1 and Type 2 diabetes. The condition, now named Type 5 diabetes, was announced by Prof Peter Schwarz, president of the International Diabetes Federation, at the World Congress of Diabetes 2025 held in Bangkok this week, a TOI report stated.

Distinct from Type 1 and Type 2

Type 5 diabetes affects people who are underweight, lack a family history of diabetes and do not show the typical symptoms of Type 1 or Type 2 diabetes. Dr Nihal Thomas, professor in the department of endocrinology at Christian Medical College (CMC), Vellore, said, “People living with Type 5 diabetes are typically underweight, have no family history of diabetes and show symptoms that do not quite match Type 1 or Type 2 diabetes.”

The condition was first observed in the 1960s and referred to as J-type diabetes, after being detected in Jamaica. It was classified by the World Health Organisation in 1985, but removed in 1998 due to lack of physiological evidence. At the time, experts believed it to be a misdiagnosed case of Type 1 or 2 diabetes. New research has since confirmed that Type 5 is different.

Research establishes physiological differences

In 2022, Dr Thomas and Dr Riddhi Dasgupta from CMC, along with Prof Meredith Hawkins of Albert Einstein College of Medicine, New York, studied the condition and identified key physiological differences. The findings were published in the journal Diabetes Care.

“Those with Type 5 are insulin deficient, but not insulin resistant. This is a key difference from Type 2 diabetes, where the body resists insulin's action despite producing it,” Dr Thomas said.

Found mostly in low-resource settings

People with Type 5 usually have a body mass index (BMI) of less than 18.5 kg/m². The condition has been linked to poor nutrition after birth in babies born with low weight. Unlike Type 1 diabetes, patients with Type 5 do not show the usual antibodies. “Also, about 50% of them could be managed with tablets, not insulin. This is important as Type 5 is mostly seen in areas of low resources,” Dr Thomas said.

In India, the condition is more common in regions with lower gross domestic product (GDP).

Growing global attention

After the Diabetes Care study, Scientific American published a review article in 2023 that brought wider attention to the condition. A global task force has now been formed to study the epidemiology and biology of Type 5 diabetes.

Dr Thomas clarified that Type 5 should not be confused with MODY-5 (Maturity Onset Diabetes of the Young), which is caused by specific genetic mutations. “There are about 25 to 30 million cases of Type 5 diabetes worldwide, perhaps more,” he added.