Molecular Characterization and Management of Congenital Hyperinsulinism: A Tertiary Centre Experience

Background: There is limited data from India regarding medical management of congenital hyperinsulinism (CHI). Objective: To study the molecular diagnosis, medical management and outcomes of children with CHI. Study design: Ambispective. Participants: Children with CHI admitted in from December, 2011 till March, 2020 at a tertiary care referral hospital. Outcomes: Clinical and genetic profile, treatment, and response Results: 42 children with a median age of 3 days (range 1 day to 6 years) were enrolled, of which 23 (54.7%) were diazoxideresponsive. Mutations were identified in 28 out of 41 (68.2%) patients. The commonest gene affected was ABCC8 in 22 patients. The pathogenic variant c.331G>A in ABCC8 gene was identified in 6 unrelated cases from one community. Good response to daily octreotide was seen in 13 of the 19 (68.4%) diazoxide-unresponsive patients. Monthly long-acting octreotide was initiated and daily octreotide could be stopped or tapered in 9 patients. Sirolimus was tried with variable response in 6 patients but was discontinued in 5 due to adverse effects. Four patients had focal CHI, of which one underwent partial pancreatic resection. The disease severity reduced with age and neurodevelopment was good in the patients with identifiable genetic defects who were optimally managed. Conclusions: Medical management of CHI is effective, if compliance can be ensured, with good quality of life and neurological outcomes.

Mutations in K ATP channel genes and congenital hyperinsulinemic hypoglycemia / 国际儿科学杂志

Congenital hyperinsulinemic hypoglycemia(CHH)is a group of rare heterogeneous diseases with hypoglycemia as the main clinical manifestation caused by insulin imbalance and excessive secretion.It is the most common cause of persistent hypoglycemia in infants and children.Related gene mutations were detected in about 40% of patients, among which inactivating mutations in ABCC8 or KCNJ11 genes are the most common.Delay in diagnosis and improper treatment can cause permanent brain damage in infants and children with CHH.Therefore, early identification and correct diagnosis and treatment are important and essential to prevent brain damage in infants and children with CHH.This article reviews the molecular pathogenesis of CHH caused by K ATP gene inactivation mutations, the impact of ABCC8 or KCNJ11 gene mutations on the pathological types of pancreas, the severity of hypoglycemia and the choice of clinical treatment options in children with CHH, as well as the latest progress in clinical diagnosis and treatment of CHH, in order to improve clinicians′ awareness of CHH.

Clinical and Genetic Heterogeneity of Familial Early-Onset Diabetes: Case of Six Tunisian Patients Suspected of Maturity-Onset Diabetes of the Young 12

Background and objective: Maturity-onset diabetes of the young 12 (MODY12) is a form of early-onset type 2 diabetes, which is transmitted in an autosomal dominant mode. It has clinical features similar to MODY1 and MODY3. The aim of this study is to screen for mutations in ABCC8 gene in six Tunisian patients suspected of MODY12 using Sanger sequencing. Methods: Six probands, with diabetes in 2-3 generations and found previously negative for mutations in HNF1A, HNF4A, INS, IPF1 and NEUROD1, were screened for known mutations in ABCC8 gene using Sanger sequencing. A comparison of the clinical features of our patients with MODY12 cohorts of other studies was also performed using ANOVA test. Results: The six patients were diagnosed with overt diabetes (fasting glycemia: 12.85 ± 3.5 mmol/l, HbA1c: 12.51 ± 2.58%) at mean age of 25.16 ± 5.11 years. They had a BMI mean equal to 26.7 ± 5.9 kg/m2. The majority of the patients were initially treated with OHA or on diet. Some of them converted to insulin therapy. Although, the comparison of our cohort with other MODY12 cohorts showed no significant difference in age at diagnostic and HbA1c, molecular analysis showed only two synonymous non-pathological polymorphisms rs1799857 and rs1805036. Conclusion: Our study highlighted the clinical and genetic heterogeneity of familial earlyonset diabetes in the Tunisian population, which is concordant with previous studies Thus, the need for using nextgeneration sequencing technologies to determine the aetiology of these forms of diabetes.

Clinical characteristics and gene mutations analysis of 56 patients with congenital hyperinsulinism / 中华实用儿科临床杂志

Objective To analyze the clinical characteristics and gene mutations of 56 patients with congenital hyperinsulinism(CHI)and to provide a theoretical basis for clinical diagnosis and treatment of CHI.Methods Fifty-six children who were diagnosed as CHI between February 2002 and January 2016 in Beijing Children's Hospital Affiliated to Capital Medical University were selected as research subjects.A retrospective study was done about the clinical data and the treatment procedures of the 56 patients,such as perinatal conditions,clinical manifestations,laboratory data,treatments,prognosis and so on.Polymerase chain reaction(PCR)-DNA technology or next-generation sequencing technology was used to analyze the CHI relevant genes of the 56 patients.Results Thirty of the 56 patients carried CHI gene mutation.(1)Twenty-three of 56 patients(41.0％)carried ABCC8/KCNJ11 gene mutations:4 of 23 patients carried complex heterozygous mutation,1 of 23 patients carried both ABCC8 and KCNJ11 gene mutation,1 of 23 patients carried maternally inherited ABCC8 gene mutation,12 of 23 patients carried paternally inherited ABCC8 gene mutation,1 of 23 patients carried paternally inherited KCNJ11 gene mutation,3 of 23 patients carried de novo ABCC8 gene mutation,1 of 23 patients had unknown genetic way,19 of 23 patients were treated with Diazoxide,2 of 19 patients were responsive to Diazoxide,7 of 19 patients were unresponsive to Diazoxide and 10 of 19 patients were uncertain to Diazoxide.(2)Five of 56 patients(8.9％)carried GLUD1 gene mutation,4 of 5 patients were treated with Diazoxide and they were all responsive to Diazoxide.(3)One of 56 patients(1.7％)carried de novo GCK gene mutation,responsive to Diazoxide treatment.(4)One of 56 patients(1.7％)carried maternally inherited SLC16A1 gene mutation,responsive to Diazo-xide treatment.Conclusions The ABCC8 gene and GLUD1 gene mutation are the main causative genes of CHI.The GCK gene and SLC16A1 gene mutation are in the minority.Most ABCC8 gene and KCNJ11 gene mutation are unresponsive to Diazoxide treatment.

A case report on congenital hyperinsulinism associated with ABCC8 nonsense mutation: Good response to octreotide / Journal of the ASEAN Federation of Endocrine Societies

@#<p style="text-align: justify;">A 2.4 kg baby boy born via Caesarian section at 35 weeks had the first onset of hypoglycemia at 2 hours of life. The infant required a glucose load of 30 mg/kg/min. Insulin level was 19.6 pmol/L (normal value 17.8-173.0) in the absence of ketosis. He was resistant to oral diazoxide but responded to octreotide infusion. The boy was found to be heterozygous for an ABCC8 nonsense mutation, p.R934*. We present our experience on the use of subcutaneous octreotide for 2 years for the treatment of diazoxide resistant congenital hyperinsulinism (CHI).</p>

A novel mutation of ABCC8 gene in a patient with diazoxide-unresponsive congenital hyperinsulinism / 소아과

Congenital hyperinsulinism (CHI) is a rare condition that can cause irreversible brain damage during the neonatal period owing to the associated hypoglycemia. Hypoglycemia in CHI occurs secondary to the dysregulation of insulin secretion. CHI has been established as a genetic disorder of islet-cell hyperplasia, associated with a mutation of the ABCC8 or KCNJ11 genes, which encode the sulfonylurea receptor 1 and the inward rectifying potassium channel (Kir6.2) subunit of the ATP-sensitive potassium channel, respectively. We report the case of a female newborn infant who presented with repetitive seizures and episodes of apnea after birth, because of hypoglycemia. Investigations revealed hypoglycemia with hyperinsulinemia, but no ketone bodies, and a low level of free fatty acids. High dose glucose infusion, enteral feeding, and medications could not maintain the patient's serum glucose level. Genetic testing revealed a new variation of ABCC8 mutation. Therefore, we report this case of CHI caused by a novel mutation of ABCC8 in a half-Korean newborn infant with diazoxide-unresponsive hyperinsulinemic hypoglycemia.

Association study of the ABCC8 gene variants with type 2 diabetes in south Indians.

BACKGROUND: The ABCC8 gene which encodes the sulfonylurea receptor plays a major role in insulin secretion and is a potential candidate for type 2 diabetes. The ‑3c → t (rs1799854) and Thr759Thr (C → T, rs1801261) single nucleotide polymorphisms (SNPs) of the ABCC8 gene have been associated with type 2 diabetes in many populations. The present study was designed to investigate the association of these two SNPs in an Asian Indian population from south India. MATERIALS AND METHODS: A total of 1,300 subjects, 663 normal glucose tolerant (NGT) and 637 type 2 diabetic subjects were randomly selected from the Chennai Urban Rural Epidemiology Study (CURES). The ‑3c → t and Thr759Thr were genotyped in these subjects using polymerase chain reaction‑restriction fragment length polymorphism (PCR‑RFLP) and a few variants were confirmed by direct sequencing. RESULTS: The frequency of the ‘t’ allele of the ‑3c → t SNP was found to be 0.27 in NGT and 0.29 in type 2 diabetic subjects (P = 0.44). There was no significant difference in the genotypic frequency between the NGT and type 2 diabetic group (P = 0.18). Neither the genotypic frequency nor the allele frequency of the Thr759Thr polymorphism was found to differ significantly between the NGT and type 2 diabetic groups. CONCLUSION: The ‑3c → t and the Thr759Thr polymorphisms of the ABCC8 gene were not associated with type 2 diabetes in this study. However, an effect of these genetic variants on specific unidentified sub groups of type 2 diabetes cannot be excluded.

Permanent Neonatal Diabetes Caused by a Novel Mutation.

Most cases of permanent form of neonatal diabetes mellitus (PNDM) are due to dominant heterozygous gain of function (activating) mutations in either KCNJ11 or ABCC8 genes, that code for Kir 6.2 and SUR1 subunits, respectively of the pancreatic β-cell KATP channel. We describe the interesting case of an infant with PNDM, in whom a compound heterozygous activating/ inactivating mutation was found with clinically unaffected parents, each carrying a heterozygous mutation in ABCC8, one predicting gain of function (neonatal diabetes) and the other a loss of function (hyperinsulinemia).

An ABCC8 gene mutation leading to the onset of KATP-congenital hyperinsulinism in a Chinese boy and his pedigree analysis / 中华内分泌代谢杂志

ABCC8,KCNJ11,and GLUD1 gene mutations were investigated in a male patient with congenital hyperinsulinism and his parents were also investigated.A 1484 G＞A mutation was found in the 10th exon of ABCC8 gene in the patient,which leads to amino acid substitution at the 495 residue of the sulphonylurea receptor SUR1 protein.The patient's father also carried the same heterozygous inactive mutation,while the genotype of the mother was normal,indicating that the gene mutation of the patient was paternally inherited.According to that mutation,it is deduced that the patient may suffer from the focal type of congenital hyperinsulinism.

Congenital Hyperinsulinism Caused by Mutations in ABCC8 (SUR1) Gene.

Congenital hyperinsulinism is the most frequent cause of severe, persistent hypoglycemia in infancy and childhood. We report a 2.5 year old girl with severe congenital hyperinsulinism. Mutation analysis showed that the child is a compound heterozygote for two missense mutations in the ABCC8 gene.

Genetic analysis of neonatal diabetes mellitus and its influence on treatment outcome / 中华内分泌代谢杂志

Fourteen neonatal diabetes mellitus(NDM)patients were recruited. 9 patients were treated with glyburide and the other 5 with insulin. ABCC8, KCNJ11, and INS genes were sequenced in 6 of them. Gene mutations were found in 2, 1, and 1 cases in these genes, respectively. One case with 6q24 hypomethylation and another without known mutation were also found. 8 out of 9 patients treated with glyburide reached euglycemia(88.9%). The other 5 patients with insulin therapy either died or lost contact. The results suggest that glyburide therapy is effective in neonatal diabetes mellitus, while insulin therapy may contribute to poor compliance.