Rapid genetic analysis in congenital hyperinsulinism

Area of Science:

• Pediatric Endocrinology
• Medical Genetics

Background:

• Accurate diagnosis of focal versus diffuse congenital hyperinsulinism (CHI) is critical for surgical management.
• Genetic analysis of ABCC8 and KCNJ11 mutations can differentiate focal (paternal mutation, 11p15 loss) from diffuse (maternal mutation, homozygous/compound heterozygous mutations) CHI.
• Traditional genotyping is often too slow for timely clinical decisions.

Purpose of the Study:

• To evaluate the utility of rapid genetic analysis of ABCC8 and KCNJ11 genes in guiding surgical decisions for severe, medically unresponsive congenital hyperinsulinism (CHI).

Main Methods:

• Performed rapid genetic analysis of ABCC8 and KCNJ11 genes within two weeks for four patients with severe CHI prior to pancreatic surgery.
• Correlated genetic findings with histological examination (biopsies) and positron emission tomography (PET) scans.

Main Results:

• Genetic analysis was non-informative in two patients, who were diagnosed with diffuse CHI via biopsies.
• One patient with a paternal KCNJ11 mutation was diagnosed with focal CHI, confirmed by PET scan and biopsies.
• One patient with a de novo ABCC8 mutation presented with diffuse CHI, confirmed by PET scan and biopsies.

Conclusions:

• Rapid genetic analysis of ABCC8 and KCNJ11 is valuable but should not be the sole preoperative assessment tool for CHI.
• Exceptions include cases with identified maternal, homozygous, or compound heterozygous mutations, which strongly predict diffuse disease.