Gene mutation and treatment of neonatal congenital hyperinsulinism

Abstract

Objective To summarize the gene mutation, treatment and prognosis of neonatal congenital hyperinsulinism (CHI) cases. Method The gene mutation and treatment of newborn infants who were admitted to the neonatal center of Beijing Children′s Hospital between February 2015 and February 2018 with confirmed CHI diagnosis and whole exome sequencing (WES) results were retrospectively summarized. Result Totally 8 infants (5 boys and 3girls) were included. The onset age was (13.2±6.1) h (2 h~2 d). The main clinical presentations were inactivity, seizures and poor feeding. Among the 8 patients, 3 were positively responded to diazoxide, 5 were negative and then been treated by octreotide. Among these 5 cases, 3 were positively responded to octreotide (with stable blood glucose level after discharged home and till 6 months of age) and 2 were negative to both diazoxide and octreotide (1 had partial pancreatectomy afterwards but still had 1~2 episodes pf hypoglycemia till 6 months post-operational periods, another 1 died with unknown detail information soon after the parents quit further medical intervention). All 8 cases had heterozygous gene mutations. 7 out of the 8 cases were ABCC8 gene (encoding islet beta-cell potassium channel protein sulfonylurea receptor protein SUR1) mutation on different sites including c.4414G>A, c.221G>A, c.1773C>G, c.4352T>C, c.2924-9C>T, c.4198+1G>T, c.2509C>T, c.2331G>A, c.4316A>G and c.47G>C. Among these 7 cases, 3 were complicated heterozygous mutations with completely no response to diazoxide (2 out of the 3 were positively responded to octreotide, 1 out of the 3 was negative to octreotide) and the other 4 were simple heterozygous mutations (2 out of the 4 were positively responded to diazoxide, 1 out of the 4 was negative to diazoxide but positive to octreotide, and 1 out of the 4 was negative to both diazoxide and octreotide). 1 out of the 8 cases was heterozygous GLUD1 gene mutation at c.1388A>T site and had positive therapeutic responses to diazoxide. All 5 out of the 8 cases with negative therapeutic response to diazoxide had ABCC8 gene mutation. Conclusion ABCC8 gene encoding islet beta-cell potassium channel protein sulfonylurea receptor protein SUR1 is the most common gene to have mutation in CHI. Mutations at multiple sites of this gene may cause CHI. Various therapeutic responses to medications might be related to different types of gene mutation. Key words: Hyperinsulinism; Genes; Diazoxide; Octreotide; Infant, newborn