ESPE Abstracts

Background: Clinically, hyperinsulinemic hypoglycemia (HH) can cause apnea, growth retardation and learning disorders. Early diagnosis and meticulous follow-up are of importance to prevent undesired neurological outcomes. Congenital hyperinsulinism results from eight distinct gene defects. These genes include ABCC8, KCNJ11, GLUD1, GCK, HADH, SLC16A1, HNF4A, and UCP2. The most common causes are autosomal recessive mutations of ABCC8 and KCNJ11 genes (5).

Material and method: In this study, we retrospectively reviewed seven patients with HH who was diagnosed before May 2013 and have been followed in Pediatric Endocrinology Department of Van Yüzüncü Yıl University, Medicine School. All eight patients and their parents and siblings were screened for genetic defect.

Findings: In the present study, seven patients with HH, who was diagnosed before May 2013 and have been followed in Pediatric Endocrinology Department of Van Yüzüncü Yıl University, Medicine School, were reviewed. There was consanguinity (first cousins) between parents in one patient, while there was no consanguinity in remaining seven patients. There were three girls and five boys. Age at onset of HH was within first 4 weeks of life in five patients while it was 6 weeks of age in one patient. Of the remaining patients, one was diagnosed at 6 months of age while other was diagnosed at 11 months of age. All patients were term infants with normal birth weight except two preterm boys delivered by cesarean section. In one patient (preterm infant), hyperinsulinism was resolved on the month 3 of age during follow-up and medical therapy was no longer necessary. All eight patients and their family were screened for mutations in eight distinct genes. ABCC8 and KCJN11 gene studies were completed and mutations were detected in three patients who had undergone subtotal pancreatectomy. A novel mutation (p.126K homozygote) was detected in KCJN11 gene in one patient. Parents were first cousins in the patient with mutation in XXX gene. Screening for mutations in GLUD1, GCK, HADH, SLC16A1, HNF4A, and UCP2 genes is still proceeding.

Conclusion: In the management of preterm infants with hypoglycemia, hyperinsulinism must be excluded before suggesting prematurity as the cause of hypoglycemia. Blood sampling for metabolic markers at the time of hypoglycemia and assessment of glucagon responsiveness are indispensable for diagnosis of hyperinsulinemia. Screening patients with persistent HH for gene defects will guide for genetic counseling as well as management.