Diazoxide-responsive Congenital Hyperinsulinism Research Articles

SAT165 A Novel Mutation In The HNF4α Gene (C.691C>T, P.arg231trp) Likely To Be Pathogenic For Maturity Onset Diabetes Of The Young Type 1 Presenting With Hyperinsulinemic Hypoglycemia In An Infant

Abstract Disclosure: A. Rodriguez: None. S. Sastry: None. W. Chemaitilly: None. N. Gurtunca: None. Background: Maturity Onset Diabetes of the Young type 1 (MODY 1) is a monogenic form of diabetes mellitus caused by a defective HNF4α gene, resulting in reduced insulin secretion and diabetes in early adolescence and young adulthood. MODY 1 is also known to be associated with increased insulin secretion during fetal, neonatal and childhood periods with consequences that range from fetal macrosomia to persistent hyperinsulinism. Traditionally, HNF4α gene mutations represents 5% of all cases of diazoxide-responsive hyperinsulinism. Clinical Case: A 1 month old male born full term and large for gestational age (birth weight of 4920g) following an uncomplicated pregnancy and delivery developed hypoglycemia soon after birth and required hospital admission on day of life 2 with a serum glucose of 30 mg/dL and an insulin level of 5 uIU/mL. A fasting challenge showed hypoglycemia at 9 hours with a serum glucose of 47 mg/dL and an insulin level of 10.3 uIU/mL confirming hyperinsulinemic hypoglycemia. He was started on diazoxide to which he responded well and was placed on a continuous glucose monitor (CGM). He was originally started on diazoxide 8mg/kg/day that later was decreased to 6.6mg/kg/day due to blood glucoses in the 200’s. He passed the fasting study 5 days after starting diazoxide and went home with the CGM with subsequent dose titration made with guidance from remote data sharing. A neonatal hypoglycemia panel was sent and showed a novel mutation, c.691C>T, p.ARG231Trp in the HNF4α gene classified as a variant of uncertain significance. Computer modeling software suggested that this gene might disrupts the gene structure and function. This variant is present in population databases at a 0.0009% frequency and this missense change has been observed in individuals with clinical features of maturity onset diabetes of the young. Patient’s father carries the same mutation and paternal grandmother carries a diagnosis of type 2 diabetes mellitus. Conclusion: This is a novel mutation that should be considered pathogenic based on this patient’s neonatal presentation and previous literature. This case also presents possible uses of CGM in infants with diazoxide responsive congenital hyperinsulinism in order to decrease burden from monitoring and streamline communication with the medical team Presentation: Saturday, June 17, 2023

Octreotide-LAR is a Useful Alternative for the Management of Diazoxide-Responsive Congenital Hyperinsulinism.

The data on the congenital hyperinsulinism (CHI) in Asian Indian patients is limited. Diazoxide is often unavailable in India, which poses challenge in managing CHI. The study was aimed to present our experience with CHI with a special focus on the effectiveness and cost-effectiveness of octreotide long-acting release (OCT-LAR) among diazoxide-responsive CHI. The data of 14 index cases with CHI registered at our center were retrospectively analyzed. The diagnosis of CHI was based on elevated serum insulin (3.4-32.5 μIU/ml) and C-peptide (0.58-1.98 ng/ml) at the time of symptomatic hypoglycemia (BG≤41 mg/dl). Fourteen patients (13 males) presented at a median (range) age of 3 (1-270) days, seizures being the most common mode of presentation (78.6%). Ten patients were diazoxide-responsive, two were partially responsive, while two were unresponsive. Genetics was available for eight patients; ABCC8 (n=3, 1 novel) and HADH (n=2, both novel) were the most commonly mutated genes. OCT-LAR was offered to eight patients including four with diazoxide-responsive disease and was universally effective. We propose a cost-effective approach to use OCT-LAR in the management of CHI, which may also make it more cost-effective than diazoxide for diazoxide-responsive disease. Five of the 11 (45.5%) patients had evidence of neurological impairment; notably, two patients with HADH mutations had intellectual disability despite diazoxide-responsiveness. We report three novel mutations in CHI-associated genes. We demonstrate the effectiveness of and propose a cost-effective approach to use OCT-LAR in diazoxide-responsive CHI. Mutations in HADH may be associated with abnormal neurodevelopmental outcomes despite diazoxide-responsiveness.

SUN-690 HNF4A Mutation in Siblings with Diazoxide Responsive Congenital Hyperinsulinism

Background: Congenital hyperinsulinism (HI) is the leading cause of severe, persistent hypoglycemia in infants. Transient HI seen at risk neonates due to prenatal stress and some of the congenital HI cases due to mutations in K-ATPase channel are responsive to diazoxide. It is not a common practice to obtain genetic evaluation for diazoxide responsive HI. However, children with dominant inactivating variants in HNF4A gene may present with diazoxide-responsive HI and mimic transient HI in infancy. Objective: To describe two siblings with diazoxide responsive HI with HNF4A mutation associated with maturity onset diabetes of youth type 1 (MODY1). Clinical Case: Case 1, term female with macrosomia and Case 2, preterm male appropriate for gestational age were born to same mother without gestational diabetes and with no perinatal stress. Siblings were non-dysmorphic and both presented with hypoglycemia during first week of life. Diagnosis of HI is confirmed based on inappropriately suppressed β-hydroxybutyrate at the time of hypoglycemia and inappropriate glycemic response to glucagon consistent with increased insulin action. Both siblings responded to diazoxide therapy. Family history was significant for late-onset diabetes in paternal extended family. Case 1 required very low dose diazoxide (2 mg/kg/day) during first year of life to sustain normoglycemia. She came off of diazoxide at 19 months of age. Case 2 is normoglycemic on 5mg/kg/day diazoxide at 4 months of age. Genetic evaluation through whole exome sequencing pursued upon diagnosis of Case 2 revealed paternally inherited heterozygous pathogenic start loss variant in HNF4A gene (c.3G>T) in both siblings. Father was completely asymptomatic without any history of hypo- or hyperglycemia. Conclusion: HNF4A gene encodes hepatocyte nuclear factor-4-alpha that regulates hepatic gluconeogenesis and lipid metabolism. Dominant inactivating variants in HNF4A gene associated with familial HI, are typically associated with increased size for gestational age, mild diazoxide-responsive hypoglycemia (which may be transient) and monogenic diabetes during adolescence. HNF4A mutations were described as one of the most common genetic cause of diazoxide-responsive congenital hyperinsulinism and are associated with MODY1. It is important to consider genetic evaluation in diazoxide responsive HI cases. Identifying children with HNF4A variant early on will impact their long-term follow-up leading to earlier diagnosis and treatment of MODY-1 and potentially improve long-term outcomes.

SUN-270 Heterozygous Mutation in ABCC8 in a Pedigree with Congenital Hyperinsulinism, Multiple Macrosomic Stillbirths, and Adult-Onset Diabetes Mellitus

ABCC8 encodes the SUR-1 subunit of the ATP-sensitive potassium (K-ATP) channel on beta cells. Mutations in this gene are associated with K-ATP channel gain of function (diabetes mellitus) and loss of function (hyperinsulinism). We describe a family with a heterozygous variant of uncertain significance (VUS) in the ABCC8 gene that may be associated with both diabetes mellitus and congenital hyperinsulinism. A macrosomic boy (birth weight 3.86kg; >99th centile) was born to a mother with type 2 diabetes. On day 7 of life he was diagnosed with hyperinsulinism based on an insulin of 46.1mIU/L (2.6-24.9) and glucose of 2.2mmol/L. He responded to diazoxide and his hypoglycaemia appeared to resolve by 6 months old. The boy had an older half-sister who was also macrosomic at birth (>99th centile) and had diazoxide-responsive congenital hyperinsulinism which required treatment until two years of age. He also had an older brother who was stillborn with severe macrosomia at 36 weeks weighing 5.7kg (well above 99th centile). There was a family history of stillbirth of very macrosomic babies in five cases across two generations from three mothers. The boy’s mother was macrosomic and possibly hypoglycaemic as a neonate. She developed gestational diabetes in all of her pregnancies and diabetes at age 30 years. There is also adult-onset diabetes mellitus in the boy’s maternal grandmother, maternal great-aunt and maternal great-grandmother (diagnosed in the fourth or fifth decade). The cases of hyperinsulinism/foetal macrosomia and adult-onset diabetes follow an autosomal dominant pattern. Hyperinsulinism gene panel analysis revealed a heterozygous missense mutation in the ABCC8 gene (Ala1457Thr) in the boy, which was then found in his half-sister and mother. The VUS is in a highly conserved region of the SUR1 subunit and in-silico analysis tools suggest a deleterious effect. It has been reported in cases of hyperinsulinism (MacMullen 2011) and adult-onset diabetes mellitus (Ovsyannikova 2016), but never within the same pedigree. Genetic testing of other affected and unaffected family members is underway. This case suggests that a single heterozygous mutation (Ala1457Thr) in ABCC8, currently listed as VUS, may be responsible for both loss of function (hyperinsulinism) and gain of function (diabetes mellitus) of the K-ATP channel within a single pedigree. References MacMullen, C, Zhou, Q, Snider, E, Tewson, P, Becker, S, Aziz, A, Stanley, C. (2011). Diazoxide-Unresponsive Congenital Hyperinsulinism in Children With Dominant Mutations of the β-Cell Sulfonylurea Receptor SUR1. Diabetes, 60(6), 1797-1804. doi:10.2337/db10-1631 Ovsyannikova, A, Rymar, O, Shakhtshneider, E, Klimontov, V, Koroleva, E, Myakina, N, & Voevoda, M (2016). ABCC8 Related Maturity Onset Diabetes of the Young (MODY12) Clinical Features and Treatment Perspective. Diabetes Therapy, 7(3), 591-600. doi:10.1007/s13300-016-0192-9

Congenital Hyperinsulinism in China: A Review of Chinese Literature Over the Past 15 Years.

Objective:Congenital hyperinsulinism (CHI) is a rare but severe cause of hypoglycemia. The present study investigates the clinical presentation, therapeutic outcomes and genetic mutations of CHI in Chinese individuals over the past 15 years.Methods:The authors retrospectively reviewed one case in their department and 206 cases reported from January 2002 to October 2016 in China. PubMed, Ovid Medline, Springer and Wanfang Database, CBMD database, and CKNI database were the sources used to collect the data.Results:In total, 207 cases were recruited. Of these, the ages of 100 (48.3%) were within the 4th week after birth. Seventy-seven cases (37.2%) were born large for gestational age (LGA). Seizures occurred in 140 cases (67.6%). Among 140 cases (67.6%) who were administered diazoxide treatment, 90 (64.3%) were responsive. Seven cases (3.4%) received octreotide treatment and 19 cases (9.2%) underwent surgery. 63/129 cases (48.8%) were detected to have gene mutations, including ABCC8 (69.8%), KCNJ11 (12.7%), GLUD1, GCK, HADH, and HNF4A. Among the diazoxide-unresponsive cases, gene mutations were detected in 20/36 (55.6%) cases with ABCC8 and in 2 (5.6%) cases with KCNJ11. Among the diazoxide-responsive cases, gene mutations were detected in 8 patients with ABCC8, 4 with KCNJ11, 5 with GLUD1, and 1 with GCK.Conclusion:The present study indicates that most CHI cases occurred in neonates and that 1/3 of the cases were born LGA. ABCC8 and KCNJ11 are the most common gene mutations. More than half of the diazoxide-unresponsive CHI detected mutations are in ABCC8 and KCNJ11 genes. The GLUD1 gene mutations cause diazoxide-responsive CHI. Identifying the gene mutations can assist in the diagnosis and treatment of CHI.

AB076. Congenital hyperinsulinism due to mutation of HNF4A: a case report.

Background Hyperinsulinemic hypoglycemia (HH) is the commonest cause of persistent hypoglycemia in the neonatal and infancy periods. HNF4A mutations are the third most common cause of diazoxide responsive congenital hyperinsulinism. Individuals carrying HNF4A mutations that result in familial monogenic diabetes later in life can present in early infancy with hyperinsulinism. The study was to describe a child associated with HH due to mutations in the HNF4A gene.

Congenital hyperinsulinism: clinical and molecular characterisation of compound heterozygous ABCC8 mutation responsive to Diazoxide therapy.

BackgroundMutations in ABCC8 and KCNJ11 are the most common cause of congenital hyperinsulinism (CHI). Recessive as well as dominant acting ABCC8/KCNJ11 mutations have been described. Diazoxide, which is the first line medication for CHI, is usually ineffective in recessive ABCC8 mutations. We describe the clinical and molecular characterisation of a recessive ABCC8 mutation in a CHI patient that is diazoxide response.Clinical caseA term macrosomic female infant presented with symptomatic persistent hypoglycaemia confirmed to be secondary to CHI. She exhibited an excellent response to moderate doses of diazoxide (10 mg/kg/day). Molecular genetic analysis of the proband confirmed a biallelic ABCC8 mutation – missense R526C inherited from an unaffected mother and a frameshift c.1879delC mutation (H627Mfs*20) inherited from an unaffected father. Follow-up highlighted persistent requirement for diazoxide to control CHI. Functional analysis of mutants confirmed them to result in diazoxide-responsive CHI, consistent with the clinical phenotype.ConclusionBiallelic ABCC8 mutations may result in diazoxide-responsive CHI. Irrespective of the molecular genetic analysis results, accurate assessment of the response to diazoxide should be undertaken before classifying a patient as diazoxide-responsive or unresponsive CHI.

Reduced Glycemic Variability in Diazoxide-Responsive Children with Congenital Hyperinsulinism Using Supplemental Omega-3-Polyunsaturated Fatty Acids; A Pilot Trial with MaxEPAR

Objective: Congenital hyperinsulinism (CHI) is a rare condition of hypoglycemia where therapeutic options are limited and often complicated by side-effects. Omega-3-polyunsaturated fatty acids (PUFA), which can suppress cardiac myocyte electrical activity, may also reduce ion channel activity in insulin-secreting cells. PUFA supplements in combination with standard medical treatment may improve glucose profile and may reduce glycemic variability in diazoxide-responsive CHI.Design: Open label pilot trial with MaxEPAR liquid (eicosapentaenoic and docosahexaenoic acid) PUFA (3 ml/day for 21 days) in diazoxide-responsive CHI patients (https://eudract.ema.europa.eu/, EudraCT number 201100363333).Methods: Glucose levels were monitored pre-treatment, end of treatment, and at follow-up by subcutaneous continuous glucose monitoring systems (CGMS) in 13 patients (7 girls) who received PUFA. Outcome measures were an improved glucose profile, reduced glycemic variability quantified by a reduction in the frequency of glucose levels <4 and >10 mmol/l, and safety of PUFA. All children were analyzed either as intention to treat (n = 13) or as per protocol (n = 7).Results: Mean (%) CGMS glucose levels increased by 0.1 mmol/l (2%) in intention to treat and by 0.4 mmol/l (8%) in per protocol analysis (n = 7). The frequency of CGMS <4 mmol/l was significantly less at the end of treatment than in the pre-treatment period [556 (7%) vs. 749 (10%)]. Similarly, the frequency of CGMS >10 mmol/l, was also less at the end of treatment [27 (0.3%) vs. 49 (0.7%)]. Except for one child with increased LDL cholesterol, all safety parameters were normal.Conclusion: MaxEPAR was safe and reduced glycemic variability, but did not increase glucose profiles significantly in diazoxide-responsive CHI. The supplemental value of PUFA should be evaluated in a comprehensive clinical trial.

The evolving course of HNF4A hyperinsulinaemic hypoglycaemia—a case series

Hepatocyte nuclear factor4 alpha (HNF4A) gene mutations have a well-recognized role in maturity-onset diabetes of the young and have recently been described in congenital hyperinsulinism. A biphasic phenotype has been postulated, with macrosomia and congenital hyperinsulinism in infancy, and diabetes in young adulthood. In this case series, we report three children with HNF4A mutations (two de novo) and diazoxide-responsive congenital hyperinsulinism, highlighting the potential for ongoing diazoxide requirement and the importance of screening for these mutations even in the absence of family history. All patients presented with macrosomia (mean birthweight 4.26kg) and hyperinsulinaemic hypoglycaemia soon after birth (median age 1day). All three (age range 7months to 11years 10months) remain on diazoxide therapy, with dose requirements increasing in one patient. There was no prior family history of diabetes, neonatal hypoglycaemia or macrosomia. Parents were screened for HNF4A mutations post-diagnosis and one father was subsequently found to have maturity-onset diabetes of the young. This case series follows the evolving course of three patients with confirmed HNF4A-mediated congenital hyperinsulinism, highlighting (1) the variable natural history of these mutations, (2) the potential for prolonged diazoxide requirement, even into adolescence, and (3) the need for screening, regardless of family history.