Genetic analysis of italian patients with congenital hyperinsulinism of infancy.

Background/Aims: Congenital hyperinsulinism of infancy is a rare disease that needs prompt treatment to avoid brain damage. There are currently no data regarding the clinical and molecular features of Italian patients. Methods: Thirty-three patients with HI and their parents were included. Consanguinity was reported in six patients. Half of patients were macrosomic at birth. None had raised 3-hydroxybutyrylcarnitine or hyperammonemia. Molecular analysis of ABCC8 and KCNJ11 genes was performed in all patients, and subjects with no mutation underwent analysis of HNF4A and GCK. GLUD1 and HADH genes were analyzed in a patient with leucine sensitivity. Results: Mutations in the ABCC8 and KCNJ11 genes were found in 45% of the patients (6 novel). No mutations in HNF4A, GLUD1 and GCK genes were found. Recessive mode of inheritance was found in 21% of patients. A single heterozygous mutation was identified in 24% of probands. 72% of the patients were responsive to medical treatment, and 44% of the 17 patients with no identified mutation achieved spontaneous remission. Nine children, unresponsive to medical therapy, underwent pancreatectomy. Conclusion: This is the first report on hyperinsulinism of infancy in Italy, confirming the complexity of the clinical forms and the heterogeneity of the genetic causes of the disease.