A wide spectrum of pathogenic variant types has been identified in ABCC8 and KCNJ11. These include single-nucleotide variants (SNVs), small insertions and deletions (indels), canonical and non-canonical splicing variants, deep intronic variants that disrupt normal RNA processing, and copy-number variants such as exon-level deletions or duplications. Collectively, hundreds of distinct disease-causing variants have been described across these genes, highlighting marked genetic heterogeneity. We have written and published comprehensive mutation update articles for both ABCC8 and KCNJ11, summarising the expanding variant spectrum and its clinical relevance.
🧬 Gene Summary: ABCC8 and KCNJ11
Also called SUR1 and Kir6.2, the K-ATP channel genes
What do the ABCC8 and KCNJ11 genes do?
In simple terms, these two genes provide instructions to make a channel in the pancreas that helps to control when insulin is released. The channel acts like a “gatekeeper,” making sure insulin is released only when blood sugar is high enough.
How can changes in the ABCC8 and KCNJ11 genes cause hyperinsulinism?
When ABCC8 or KCNJ11 do not work properly, the pancreas may release too much insulin, even when blood sugar is low. This can lead to repeated episodes of low blood sugar (hypoglycemia), especially in newborns and infants.
How common are changes in the ABCC8 and KCNJ11 genes in hyperinsulinism?
Very common, changes in these two genes are the most common genetic cause of congenital hyperinsulinism.
How are changes in the ABCC8 and KCNJ11 genes inherited?
Changes in these genes can be inherited in different ways:
- Recessive inheritance
- Both parents usually carry one non-working copy of the gene
- Parents are typically not affected
- Dominant inheritance
- One non-working copy of the gene can cause hyperinsulinism
- A parent may have mild symptoms or none at all
- New (de novo) changes
- Sometimes the gene change happens for the first time in the child
💡 A genetic counsellor can explain what this means for your family and future children. See also our section on Inheritance.
What does an ABCC8 or KCNJ11 change mean for my child?
Children with ABCC8 or KCNJ11-related hyperinsulinism may:
- Have low blood sugar starting shortly after birth
- Need frequent feeds, medication, or IV glucose
- Have symptoms that range from mild to severe
Some children improve over time, while others need longer-term treatment.
How does this affect treatment?
Knowing that a child has an ABCC8 or KCNJ11 gene change helps doctors decide:
- If imaging of the pancreas (such as PET scanning) is needed
- Whether surgery could be helpful
- How closely blood sugars need to be monitored
Sometimes changes in these genes cause focal hyperinsulinism, which may be treatable with limited surgery.
Where can I learn more or get support?
- Talk with your child’s hyperinsulinism care team
- Meet with a genetic counsellor
- Connect with hyperinsulinism family support organizations
🔍 Looking for more technical information?
Clinicians and researchers can view detailed information here.
How variants in these genes cause hyperinsulinism
The ABCC8 and KCNJ11 genes encode the SUR1 and Kir6.2 subunits of the pancreatic ATP-sensitive potassium channel. Inactivating (loss-of-function) variants in the KCNJ11 or ABCC8 genes are the most common known cause of congenital hyperinsulinism.
Clinical presentation
Many individuals with this form present with hyperinsulinaemic hypoglycaemia within the first few days of life. Individuals are often macrosomic as a results of increased insulin secretion in utero, where it acts as a growth factor. Many children, but not all, show poor response to the drug diazoxide. This is because diazoxide works by binding to the SUR1 subunit of the KATP channel.