Scientists discover rare new type of diabetes affecting newborns worldwide

Diabetes is usually thought of as a lifelong condition that develops later in childhood or adulthood. But new research shows that in some babies, the disease can begin within days of birth. Scientists have now identified a rare, previously unknown genetic form of neonatal diabetes that also affects brain development and causes seizures.

The study, titled Recessive TMEM167A variants cause neonatal diabetes, microcephaly, and epilepsy syndrome and published in The Journal of Clinical Investigation, found that changes in a little-known gene called TMEM167A prevent the body from making and releasing insulin properly in early life. By studying affected children from different countries and using advanced stem cell techniques, researchers showed that this single gene plays a critical role in both insulin-producing cells and the developing brain.

Neonatal diabetes is a rare condition diagnosed within the first six months of life. Unlike type 1 or type 2 diabetes, it is almost always genetic. Babies with neonatal diabetes cannot produce enough insulin from birth and require insulin treatment immediately.

More than 85 per cent of neonatal diabetes cases are linked to single-gene mutations. What makes this newly identified form distinct is that it does not affect blood sugar alone but also interferes with early brain development.

<>What did researchers discover about the TMEM167A gene?

The researchers identified recessive mutations in the TMEM167A gene in six children from different parts of the world. All of them developed diabetes very early in life, often within days or weeks of birth.

Crucially, every child also had severe microcephaly, meaning the brain and head were much smaller than expected, and most experienced epileptic seizures. This combination places the condition under a rare disorder known as microcephaly, epilepsy and diabetes syndrome (MEDS), with TMEM167A now confirmed as a new genetic cause.

Why does one gene affect both insulin production and the brain?

According to the study, the pancreas and the brain both rely heavily on cellular systems that correctly process and transport proteins.

TMEM167A is involved in moving newly made proteins from the endoplasmic reticulum to the Golgi apparatus, a cellular sorting centre. When this transport system fails, insulin-producing beta cells become stressed and eventually die. Neurons, particularly during early brain development, are similarly vulnerable to this disruption.

All six children in the study developed diabetes before six months of age and required insulin from diagnosis. Brain scans revealed profound abnormalities, including microcephaly and, in some cases, smooth brain surfaces caused by disrupted neuronal migration.

Five of the six children developed epilepsy early in life, underscoring the severity of the condition. The findings highlight the importance of early genetic diagnosis for both clinical care and family counselling.

The researchers recommend that TMEM167A be added to genetic testing panels for neonatal diabetes and congenital microcephaly. Identifying the precise genetic cause can help clinicians anticipate complications, guide treatment decisions and inform families about recurrence risks in future pregnancies.