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Familial hyperinsulinism (ABCC8-related)

Familial hyperinsulinism (FHI) causes an overproduction of insulin, which leads to low blood sugar, also known as hypoglycemia. Within the first few days and weeks after birth, babies with FHI become lethargic, irritable, have low muscle tone and feeding problems. If the condition is not managed properly, repeated episodes of hypoglycemia can increase the risk of serious complications, including seizures, respiratory problems, brain damage, and early death.

It is important to note that males of Ashkenazi Jewish ethnicity have a 1 in 540 chance (0.19%) of having a child with a type of this condition called “Focal” FHI, even if their female reproductive partner is not a carrier of FHI.

Focal FHI refers to a condition in which an isolated area of the pancreas overproduces insulin but the remainder of the pancreas produces insulin normally. Focal FHI occurs when an FHI genetic change is inherited from a carrier father, then, during the prenatal development of the pancreas, a second change spontaneously occurs in some of the pancreatic cells. With focal FHI, symptom severity, age of onset, and treatment vary depending on the individual.

Quick facts about familial hyperinsulinism (ABCC8-related)
Genes: ABCC8
Inheritance: Autosomal Recessive
Alternative Names: FHI
Relevant resources for familial hyperinsulinism (ABCC8-related)

A quick genetics rundown

As humans we have about 23,000 genes. These genes are like tiny instruction manuals that influence our health, growth and development. We inherit half of our genes from our biological mum and the other half from our biological dad. These genes are lined up on structures called chromosomes. Most of us have 23 pairs of chromosomes. The first 22 pairs are called autosomes and for the most part - these are the same among men and women. The 23rd pair determine our sex - two X chromosomes for a female and one X and one Y chromosome for males.

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How is familial hyperinsulinism (ABCC8-related) inherited?

familial hyperinsulinism (ABCC8-related) is known as an autosomal recessive condition. For autosomal recessive conditions, if a person has a variation in one copy of their gene, they are a carrier. This means that they are healthy because they also have a working copy of the gene. But, they can still pass their non-working copy to their child.

If the other parent also happens to be a carrier of the same gene, there is a 25% (1 in 4) chance that they both pass this gene variation on to their child — and as such, have a child affected by the condition.

If both parents are carriers of familial hyperinsulinism (ABCC8-related), there's a one in four chance that their children could develop symptoms.

What is carrier screening?

Carrier testing is like a checkup for your genes. It tests to see if you carry a gene variation that could cause a serious genetic condition in your child. Eugene offers an inclusive genetic carrier screening panel that includes familial hyperinsulinism (ABCC8-related), but there's a total 301 conditions that can be tested.

Eugene's carrier test is a clinical grade test that can be done from the comfort of your own home — it's just a saliva test. You're also paired with a genetic counsellor who provides mindful support and guidance every step of the way.

Learn more about carrier screening

Should parents screen for familial hyperinsulinism (ABCC8-related) before or early in pregnancy?

The biggest benefit of screening for familial hyperinsulinism (ABCC8-related) is that it can help future parents understand their reproductive risk so they can be ready and empowered to make more informed decisions. If neither partner are carriers, it provides reassurance and peace of mind that the risk of having a child with a genetic condition is low.

Since 90% of children that have a recessive genetic condition like familial hyperinsulinism (ABCC8-related) had no previous family history of it, it often feels completely out of the blue for the parents. Getting screened is a way to know this risk in advance, which can help familes manage or even prevent the condition in the first place.