Transient neonatal diabetes with two novel mutations in the KCNJ11 gene and response to sulfonylurea treatment in a preterm infant

Neonatal diabetes mellitus (NDM) is a rare condition that can be either transient or permanent. K(ATP) channel (Kir6.2 or SUR1) mutation, chromosome 6 abnormalities, insulin, or glucokinase gene mutations can lead to isolated NDM. Cases caused by Kir6.2 mutation usually result in permanent NDM (PNDM) rather than transient NDM (TNDM). The majority of patients with the Kir6.2 or SUR1 mutation can be successfully managed with a sulfonylurea agent, without the need for insulin. We report a preterm male with NDM having two novel missense mutations, E322A and D352H, in the KCNJ11 gene. At 2 months of age, successful transition from insulin to glibenclamide (glyburide) therapy of the patient was managed. At 5 months of age, his diabetes went in to remission.     

Medical and developmental impact of transition from subcutaneous insulin to oral glyburide in a 15‐yr‐old boy with neonatal diabetes mellitus and intermediate DEND syndrome: extending the age of KCNJ11 mutation testing in neonatal DM

Mohamadi A, Clark LM, Lipkin PH, Mahone EM, Wodka EL, Plotnick LP. Medical and developmental impact of transition from subcutaneous insulin to oral glyburide in a 15‐yr‐old boy with neonatal diabetes mellitus and intermediate DEND syndrome: extending the age of KCNJ11 mutation testing in neonatal DM. Mutations in the KCNJ11 gene, which encodes the Kir6.2 subunit of the ATP‐sensitive potassium channel, often result in neonatal diabetes. Patients with this mutation have been successfully transitioned from insulin to sulfonylurea (SU) therapy without compromise in their glycemic control. Among patients with neonatal diabetes due to KCNJ11 mutations, approximately 25% have neurological findings including developmental delay, motor dysfunction, and epilepsy, known as DEND syndrome. There have been rare cases of juvenile patients with intermediate DEND syndrome (iDEND) reporting variable improvement in neurological function following transition from insulin to SU treatment. We describe the response to glyburide in a 15‐yr‐old boy with severe global developmental delays resulting from the KCNJ11 mutation V59M. The patient was discovered to have diabetes mellitus at 11.5 months of age, making this the oldest age at diagnosis of a KCNJ11 mutation‐related case of neonatal diabetes. Because consensus has been to screen patients for this mutation only if younger than 6 months at the time of diagnosis, we suggest that all patients under the age of 12 months at diagnosis should receive genetic testing for monogenic causes of diabetes.     

Permanent neonatal diabetes due to KCNJ11 gene mutation

Permanent neonatal diabetes mellitus (PNDM) is characterized by the onset of diabetes within the first six months of life and insulin dependence life long. It has been recently discovered that mutation in KCNJ11 gene encoding Kir6.2, the pore forming subunit of ATP sensitive potassium channel (K_ATP) is the most common cause and such patients may respond better to oral sulphonylurea drugs than insulin. Here is a rare case of permanent neonatal diabetes due to R201C mutation in KCNJ11 gene.     

Permanent neonatal diabetes mellitus due to KCNJ11 mutation in a Portuguese family: transition from insulin to oral sulfonylureas

Permanent neonatal diabetes mellitus (PNDM) is a rare form of diabetes diagnosed within the first 6 months of life. Heterozygous activation mutations in KCNJ11, encoding the Kir6.2 subunit of the ATP-sensitive potassium (K(ATP)) channel, which acts as a key role in insulin secretion regulation, account for about half of the cases of PNDM. The majority of the patients represent isolated cases resulting from de novo mutations. Approximately 20% have associated neurologic features: the most severe form, which includes epilepsy and developmental delay, is called developmental delay, epilepsy, and neonatal diabetes (DEND) syndrome and the milder form, with less severe developmental delay and without epilepsy, is designated intermediate DEND syndrome. Individuals with KCNJ11 mutations have been successfully transitioned from insulin to sulfonylurea (SU) therapy. Furthermore, there have been cases reported with variable improvement in neurological function following a successful switching. We describe a 12-year-old Portuguese girl with PNDM due to the previously reported R201C mutation in the KCNJ11 gene. Her medical history includes prematurity and moderate developmental delay. The mutation was inherited from her mother who has isolated PNDM. The patient was successfully transferred from insulin to SU, whereas her mother showed SU resistance. Despite good glycemic control, no improvements in the cognitive performance were verified. We present our experience in switching treatment from insulin to oral SUs in this family, and also discuss whether or not the girl's developmental delay is related with the Kir6.2 mutation. To our knowledge, this is the first Portuguese patient reported with successful transition to SU treatment.     

新生儿糖尿病研究进展

新生儿糖尿病是一组异质性单基因遗传病,常被误诊为1型糖尿病.永久性新生儿糖尿病与免疫无关,主要与KCNJ 11、ABCC8和胰岛素基因等基因突变有关;多以酮症酸中毒起病,伴宫内发育迟缓、脱水.基因检测有助于疾病分型,并可根据不同致病基因进行靶向治疗.对于ATP敏感的K+通道基因突变的永久性新生儿糖尿病患儿可口服磺脲类降...     

Glyburide ameliorates motor coordination and glucose homeostasis in a child with diabetes associated with the KCNJ11/S225T,del226‐232 mutation

Gain‐of‐function mutations of KCNJ11 can cause permanent neonatal diabetes mellitus, but only rarely after 6 months of age. Specific uncommon mutations KCNJ11give rise to a syndrome defined as developmental delay, epilepsy, and neonatal diabetes (DEND), or – more frequently – to a milder sub‐type lacking epilepsy, denoted as intermediate‐DEND (iDEND). Our aim was to consider a possible monogenic etiology in a 12‐yr‐old boy with early onset diabetes and mild neurological features. We studied a subject diagnosed with diabetes at 21 months of age, and negative to type 1 diabetes autoantibodies testing. He had learning difficulties during primary school, and a single episode of seizures at the age of 10 yr. We performed direct DNA sequencing of the KCNJ11 gene with subsequent functional study of mutated channels in COSm6 cells. The patient's clinical response to oral glyburide (Glyb) was assessed. Motor coordination was evaluated before and after 6 and 12 months of Glyb therapy. Sequencing of the KCNJ11 gene detected the novel, spontaneous mutation S225T, combined with deletion of amino acids 226–232. In vitro studies revealed that the mutation results in a K_ATP channel with reduced sensitivity to the inhibitory action of ATP. Glyb improved diabetes control (hemoglobin A1c on insulin: 52 mmol/mol/6.9%; on Glyb: 36 mmol/mol/5.4%) and also performance on motor coordination tests that were impaired before the switch of therapy. We conclude that KCNJ11/S225T, del226‐232 mutation caused a mild iDEND form in our patient. KCNJ11 should be considered as the etiology of diabetes even beyond the neonatal period if present in combination with negative autoantibody testing and even mild neurological symptoms.     

Epidemiology,clinical characteristics,and genetic etiology of neonatal diabetes in Japan

Neonatal diabetes mellitus (NDM) is a rare but potentially devastating metabolic disorder, with a reported incidence of one per 300 000–500 000 births generally, and hyperglycemia develops within the first 6 months of life. NDM is classified into two categories clinically. One is transient NDM (TNDM), in which insulin secretion is spontaneously recovered by several months of age, but sometimes recurs later, and the other is permanent NDM (PNDM), requiring lifelong medication. Recent molecular analysis of NDM identified at least 12 genetic abnormalities: chromosome 6q24, KCNJ11, ABCC8, INS, FOXP3, GCK, IPF1, PTF1A, EIF2AK3, GLUT2, HNF1β, and GLIS3. Of these, imprinting defects on chromosome 6q24 and the KCNJ11 mutation have been recognized as the major causes of TNDM and PNDM, respectively, in Caucasian subjects. Although the pathogenesis and epidemiology of NDM in Japan seem to be clinically distinct, they are still unclear. In this review, we summarize the epidemiology, clinical characteristics, and genetic etiology in Japanese patients with NDM compared with the data on Caucasian patients.     

Outpatient transition of an infant with permanent neonatal diabetes due to a KCNJ11 activating mutation from subcutaneous insulin to oral glyburide

Abstract:  Neonatal diabetes mellitus is rare, may either be transient or permanent, and may be caused by mutations in any of the several different genes. Until recently, most forms of permanent neonatal diabetes required lifelong subcutaneous insulin for management; however, permanent neonatal diabetes due to activating mutations in the KCNJ11 gene, which encodes the Kir6.2 protein subunit of the ATP-sensitive K⁺ (K_ATP) channel, may be amenable to oral sulfonylurea therapy. We describe a case of an 18-month-old infant with permanent neonatal diabetes due to an activating KCNJ11 mutation successfully transitioned from subcutaneous insulin therapy to oral sulfonylurea therapy in the outpatient setting.     

Transition from insulin to glyburide in a 4-month-old girl with neonatal diabetes mellitus caused by a mutation in KCNJ11

Initial management of neonatal diabetes mellitus consists of insulin and adequate calories for growth. Once a genetic diagnosis is made, most patients with neonatal diabetes caused by mutations in the KCNJ11 gene can be successfully managed with a sulfonylurea agent without the need for insulin. We report on the transition from insulin to glyburide (glibenclamide) therapy in a 4-month-old girl with neonatal diabetes mellitus caused by a mutation in KCNJ11. Dosing of glyburide three times daily was critical for her successful transition.     

Familial permanent neonatal diabetes with KCNJ11 mutation and the response to glyburide therapy--a three-year follow-up

We describe 3 years follow-up of glyburide therapy in a child with permanent neonatal diabetes mellitus (PND) born to a 19 year-old mother with congenital diabetes mellitus. Genetic analysis identified a KCNJ11 mutation (R201H) in both the child and her mother. After 2 years of insulin therapy, the patient was switched to oral glyburide. After initial stabilization, glyburide therapy resulted in a marked decrease in glucose excursions in comparison to insulin. The patient had 3-10 episodes of hypoglycemia per week, including a total of eight episodes resulting in seizures, while on insulin. In contrast, no severe hypoglycemia was reported on glyburide. The patient's basal C-peptide was undetectable on insulin therapy (< 166 pmol/l) but was easily detectable on glyburide (189-761 pmol/l). The range of HbA1c improved significantly from 8-12% on insulin to 4.7-6% on glyburide. The frequency of glucose monitoring was gradually decreased from 4-8 times to 2-3 times a day on oral glyburide. This report confirms the superiority of sulfonylurea therapy in the treatment of PND with Kir6.2 mutations and shows sustained improved glycemic control over a 3-year follow-up period. Genetic exploration in other family members with diabetes might provide further insight into the nature of familial neonatal diabetes.     

Neonatal diabetes mellitus and KCNJ11 gene mutation: report of a family case

Neonatal diabetes mellitus (NDM) is characterized by hyperglycemia within the first month of life and insulin dependence for at least two weeks. There are two types of NDM, transient (TNDM) and permanent (PNDM), which are genetically different. We report the case of two brothers who developed hyperglycemia without ketosis on the 18th day and 2 h of life, respectively. Thyroid function tests, abdominal ultrasound and karyotype where normal and there were no pancreatic antibodies. The first one required insulin therapy for the first 92 days of life and the second for 5 months. The mother developed gestational diabetes during both pregnancies and she was later diagnosed diabetes mellitus (without antibodies). They were studied for mutations in KCNJ11 gene (principally related to the permanent form). The three of them showed the E229K mutation (frequently associated with the transient form). A genetic study is essential in NDM to achieve the most accurate prognosis possible.     

Transition from insulin to sulfonylurea in a child with diabetes due to a mutation in <Emphasis Type="Italic">KCNJ11</Emphasis> encoding Kir6.2—initial and long-term response to sulfonylurea therapy

Background  Mutations in the KCNJ11 gene encoding the adenosine triphosphate (ATP)-sensitive potassium channel (K_ATP) subunit Kir6.2 are the most frequent cause of diabetes in infancy. Sulfonylurea (SU) treatment restores insulin secretion in patients with KCNJ11 mutations. Materials and methods  We report a 9-year-old boy who presented at the age of three months with diabetic ketoacidosis. Results Sequencing of the KCNJ11 gene revealed an R201H mutation. Therefore, he was transferred from insulin to oral SU therapy. He required a high-threshold dose before insulin could be discontinued. After transition, a subsequent dose reduction was necessary to avoid hypoglycemia. Improved sustained metabolic control without complications was achieved on a low SU maintenance dose twice daily over 36 months. Conclusion  SU therapy is safe for patients with diabetes due to KCNJ11 mutations. The mechanism of a threshold dose and the twice-daily requirement needs further attention.     

Permanent neonatal diabetes with arthrogryposis multiplex congenita and neurogenic bladder – a new syndrome?

Abstract: Neonatal diabetes mellitus is a rare (1/400 000 newborns) but potentially devastating condition, which may be transient or permanent; typical symptoms occur within the first 4 wk of life. The transient form is a developmental insulin production disorder that resolves postnatally. Fifty to 60% of cases can be seen as transient form. Cases that require lifelong insulin therapy can be described as permanent condition. This fraction of cases is less common than the transient form. There are no clinical features that can predict whether a neonate with diabetes mellitus but no other dysmorphology will eventually have permanent neonatal diabetes mellitus (PNDM) or transient neonatal diabetes mellitus. Some metabolic or genetic defects such as complete deficiency of glucokinase or heterozygous activating mutations of KCNJ11, encoding Kir6.2, were found in patients with PNDM. A preterm female infant with a gestational age of 36 wk was admitted to the neonatal intensive care unit in the first hours of life due to prematurity and intra‐uterine growth retardation. She was diagnosed as having arthrogryposis multiplex congenita on the first day. Hyperglycemia was detected on the third day of life, and she required insulin treatment. The patient is now 6 yr old with PNDM, arthrogryposis multiplex, neurogenic bladder, immune deficiency, constipation, and ichthyosis. Is this a new form of neonatal diabetes mellitus?     

Incidence, genetics, and clinical phenotype of permanent neonatal diabetes mellitus in northwest Saudi Arabia

Habeb AM, Al‐Magamsi MSF, Eid IM, Ali MI, Hattersley AT, Hussain K, Ellard S. Incidence, genetics, and clinical phenotype of permanent neonatal diabetes mellitus in northwest Saudi Arabia. Background: Permanent neonatal diabetes mellitus (PNDM) in European population has an incidence of at least 1 in 260 000 live births and is most commonly due to mutations in KCNJ11 and ABCC8. However, data on this condition in other populations are limited. Objective: To define the incidence, genetic aetiology, and clinical phenotype of PNDM in Al‐Madinah region, northwest Saudi Arabia. Methods: Patients with PNDM diagnosed between 2001 and 2010 were identified and clinically phenotyped. Sequencing of KCNJ11, ABCC8, and INS were performed initially on all subjects, and EIF2AK3, GLIS3, SLC2A2, SLC19A2, GCK, IPF1, and NEUROD1 genes were sequenced according to the clinical phenotype. Results: In total, 17 patients from 11 consanguineous families were diagnosed with PNDM and the incidence was 1 in 21 196 live births. Six different mutations in four genes were identified, of which two GLIS3 and one SLC2A2 were novel and no patient had KCNJ11, ABCC8, or INS mutations. Fourteen (82.4%) patients had identifiable genetic aetiology and their PNDM was part of known autosomal‐recessive syndromes including Wolcott Rallison (41.1%), neonatal diabetes and hypothyroidism (29.4%), Fanconi‐Bickel (5.8%), and thiamine‐responsive megaloblastic anaemia (5.8%). Two patients with isolated PNDM and one with intermediate developmental delay, epilepsy and neonatal diabetes had no identifiable cause. Conclusions: Al‐Madinah region has the highest reported incidence of PNDM worldwide. In this region with high consanguinity, PNDM has different genetic aetiology and in the majority of cases presents as a part of rare familial autosomal‐recessive syndrome rather than in isolation.     

Neonatal diabetes: a disease linked to multiple mechanisms]

Transient (TNDM) and Permanent (PNDM) Neonatal Diabetes Mellitus are rare conditions occurring in about 1: 300,000 live births. In TNDM growth retarded infants develop diabetes in the first few weeks of life only to go into remission in a few months with possible relapse to a permanent diabetes state usually around adolescence or as adults. We believe that pancreatic dysfunction in this condition is maintained throughout life with relapse initiated at times of metabolic stress such as puberty or pregnancy. In PNDM, insulin secretory failure occurs in the late fetal or early postnatal period. A number of conditions are associated with PNDM, some of which have been elucidated at the molecular levels. Among those, the very recently elucidated mutations in KCNJ11 and ABCC8 gene, encoding the Kir6.2 and SUR1 subunit of the pancreatic K(ATP) channel involved in regulation of insulin secretion accounts for one third to a half of the PNDM cases. Patients with TNDM are more likely to have intrauterine growth retardation and less likely to develop ketoacidosis than patients with PNDM. In TNDM, patients are younger at the diagnosis of diabetes and have lower initial insulin requirements. Considerable overlap occurs between the two groups, so that TNDM cannot be distinguished from PNDM based on clinical features. Very early onset diabetes mellitus seems to be unrelated to autoimmunity in most instances. Recurrent diabetes is common in patients with "transient" neonatal diabetes mellitus and, consequently, prolonged follow-up is imperative. Molecular analysis of chromosome 6 anomalies, the KCNJ11 and ABCC8 genes encoding Kir6.2 and SUR1 provide a tool to identify transient from permanent neonatal diabetes mellitus in the neonatal period. This analysis also has potentially important therapeutic consequences leading to transfer some patients, those with mutations in KCNJ11 and ABCC8 from insulin therapy to sulfonylureas. Realizing how difficult it is to take care of a child of this age with diabetes mellitus should prompt clinicians to transfer these children to specialized centers. Insulin therapy and high caloric intake are the basis of the treatment. Insulin pump may offer an interesting therapeutic tool in this age group in experienced hands.     

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).     

Neonatal diabetes mellitus due to L233F mutation in the KCNJ11 gene

Background

Neonatal diabetes mellitus (NDM) due to KCNJ11 gene mutation presents with diabetes in the first 3 months of life and sometimes with neurological features like developmental delay, muscle weakness and epilepsy.

Methods

A 5-week-old boy presented with diabetic ketoacidosis. Molecular genetic analysis of the patient revealed heterozygous missense mutation, L233F in the KCNJ11 gene, while his mother was mosaic for the same mutation.

Results

The treatment strategy was changed from insulin injections to oral glibenclamide and with a better glycemic control.

Conclusion

The patient with NDM due to mutation L233F (not reported till date) in the KCNJ11 gene can be successfully treated with oral glibenclamide therapy.     

Sulfonylurea challenge test in subjects diagnosed with type 1 diabetes mellitus

Background: Patients with early onset diabetes because of defects in glucose‐stimulated insulin secretion (GSIS) may respond better to sulfonylureas than insulin treatment. Such patients include those with monogenic disorders, who can be differentiated from autoimmune type 1 diabetes mellitus (T1DM) by genetic testing. Genetic testing is expensive and unknown defects in GSIS would not be diagnosed. Aims: We propose a sulfonylurea challenge test to identify patients who have been clinically diagnosed with T1DM, but those who maintain a preferentially sulfonylurea‐responsive insulin secretion. Materials & Methods: A total of 3 healthy controls, 2 neonatal diabetes mellitus (NDM) subjects, 3 antibody‐positive (Ab+T1DM), and 12 antibody‐negative (Ab?T1DM) subjects with type 1 diabetes, were given an intravenous bolus of glucose followed by an oral dose of glipizide. Results: Healthy controls showed a robust C‐peptide increase after both glucose and glipizide, but NDM subjects showed a large increase in C‐peptide only following glipizide. As expected, 2 of 3 Ab+T1DM, as well as 11 of 12 Ab?T1DM showed no response to either glucose or glipizide. However, 1 Ab?T1DM and 1 Ab+T1DM showed a small C‐peptide response to glucose and a marked positive response to glipizide, suggesting defects in GSIS rather than typical autoimmune diabetes. Discussion: These data demonstrate the feasibility of the sulfonylurea challenge test, and suggest that responder individuals may be identified. Conclusions: We propose that this sulfonylurea challenge test should be explored more extensively, as it may prove useful as a clinical and scientific tool.     

A novel INS mutation in a family with maturity‐onset diabetes of the young: Variable insulin secretion and putative mechanisms

Insulin gene (INS) mutations cause a rare form of maturity‐onset diabetes of the young (MODY), a heterogeneous group of autosomal dominant diabetes with at least 14 confirmed causative genes. Here, we describe a family with MODY due to a novel INS mutation, detected using massively parallel sequencing (MPS). The proband presented aged 11 years with mild diabetic ketoacidosis. She was negative for IA2 and GAD antibodies. She had a strong family history of diabetes affecting both her two siblings and her mother, none of whom had ketosis but who were considered to have type 1 diabetes and managed on insulin, and her maternal grandfather, who was managed for decades on sulfonylureas. Of note, her younger sister had insulin deficiency but an elevated fasting proinsulin:insulin ratio of 76% (ref 5%‐30%). Sanger sequencing of HNF4A, HNF1A, and HNF1B in the proband was negative. Targeted MPS using a custom‐designed amplicon panel sequenced on an Illumina MiSeq detected a heterozygous INS mutation c.277G>A (p.Glu93Lys). Sanger sequencing confirmed the variant segregated with diabetes within the family. Structural analysis of this variant suggested disruption of a critical hydrogen bond between insulin and the insulin receptor; however, the clinical picture in some individuals also suggested abnormal insulin processing and insulin deficiency. This family has a novel INS mutation and demonstrated variable insulin deficiency. MPS represents an efficient method of MODY diagnosis in families with rarer gene mutations.