Babies born with abnormally high levels of insulin are at the risk of suffering permanent brain damage and life-long disability, finds a study that showed it's possible to predict when and how the condition may affect the child in the long-term.

The generally rare condition, called congenital hyperinsulinism, can also be as common as cystic fibrosis in children born into communities where cousins marry. So far, scientists understood that there were two main subtypes of the disease known as diffuse -- affects the entire pancreas -- and focal -- affects just one area of the organ.

The new study, led by a team from the University of Manchester in the UK, showed that focal CHI can be further categorised into two types -- spreading focal lesions and isolated focal lesions. Spreading focal lesions are generally larger and spread outwards into areas of healthy cells, while isolated focal lesions, have a capsule around them that keeps the diseased cells separate from healthy cells.

For the study, published in the Frontiers in Endocrinology journal, the team investigated the cases of 25 infants with focal CHI to see how the two types of lesions influenced their long-term outcomes. They found babies with spreading focal lesions suffered more severely from the disease and were diagnosed earlier. These infants were more likely to suffer brain damage, which permanently affected their development, learning and behaviour.

In contrast, in infants with isolated lesions, the disease was diagnosed later and surgery to remove the lesion was less complicated. These data help to explain why newborn babies diagnosed with the same disease may go on to have very different outcomes and could influence the way clinicians choose to manage each new case of CHI.

"One of the problems facing clinicians is that it's really difficult to predict which babies will have problems after surgical treatment," said Karen Cosgrove, from the varsity.

"Our data gives some important clues that will help clinicians to know how much extra care each baby is likely to need," Cosgrove said.