Insulin therapy in neonatal diabetes mellitus: a review of the literature

Case report: Better late than never, but sooner is better: switch from CSII to sulfonylureas in two patients with neonatal diabetes due to KCNJ11 variants

Neonatal diabetes mellitus (NDM) is a rare genetic disease characterized by severe hyperglycemia requiring insulin therapy with onset mostly within the first 6 months and rarely between 6-12 months of age. The disease can be classified into transient (TNDM) or permanent neonatal diabetes mellitus (PNDM), or it can be a component of a syndrome. The most frequent genetic causes are abnormalities of the 6q24 chromosomal region and mutations of the ABCC8 or KCNJ11 genes coding for the pancreatic beta cell's potassium channel (KATP). After the acute phase, patients with ABCC8 or KCNJ11 mutations treated with insulin therapy can switch to hypoglycemic sulfonylureas (SU). These drugs close the KATP channel binding the SUR1 subunit of the potassium channel and restoring insulin secretion after a meal. The timing of this switch can be different and could affect long-term complications. We describe the different management and clinical outcome over the time of two male patients with NDM due to KCNJ11 pathogenetic variants. In both cases, continuous subcutaneous insulin infusion pumps (CSII) were used to switch therapy from insulin to SU, but at different times after the onset. The two patients kept adequate metabolic control after the introduction of glibenclamide; during the treatment, insulin secretion was evaluated with c-peptide, fructosamine, and glycated hemoglobin (HbA1c), which were within the normal range. In neonates or infants with diabetes mellitus, genetic testing is an indispensable diagnostic tool and KCNJ11 variants should be considered. A trial of oral glibenclamide must be considered, switching from insulin, the first line of NDM treatment. This therapy can improve neurological and neuropsychological outcomes, in particular in the case of earlier treatment initiation. A new modified protocol with glibenclamide administered several times daily according to continuous glucose monitoring profile indications, was used. Patients treated with glibenclamide maintain good metabolic control and prevent hypoglycemia, neurological damage, and apoptosis of beta cells during long-term administration.

The application of precision medicine in monogenic diabetes

INTRODUCTION

Monogenic diabetes, a form of diabetes mellitus, is caused by a mutation in a single gene and may account for 1-2% of all clinical forms of diabetes. To date, more than 40 loci have been associated with either isolated or syndromic monogenic diabetes.

AREAS COVERED

While the request of a genetic test is mandatory for cases with diabetes onset in the first 6 months of life, a decision may be difficult for childhood or adolescent diabetes. In an effort to assist the clinician in this task, we have grouped monogenic diabetes genes according to the age of onset (or incidental discovery) of hyperglycemia and described the additional clinical features found in syndromic diabetes. The therapeutic options available are reviewed.

EXPERT OPINION

Technical improvements in DNA sequencing allow for rapid, simultaneous analysis of all genes involved in monogenic diabetes, progressively shrinking the area of unsolved cases. However, the complexity of the analysis of genetic data requires close cooperation between the geneticist and the diabetologist, who should play a proactive role by providing a detailed clinical phenotype that might match a specific disease gene.

Novel perspectives of super-high dose sulfonylurea and high-dose oral prednisolone in an infant with DEND syndrome due to V64M heterozygote KCNJ11 mutation

AIMS

To report a novel mutation associated with developmental delay, epilepsy, and neonatal diabetes-DEND Syndrome, responsive to a novel management combination.

METHODS

We describe the investigation, treatment, and genetic diagnosis of a newborn diagnosed with DEND syndrome.

RESULTS

The patient was found to be de-novo heterozygous for pathogenic KCNJ11 missense variant: c.190G > A, p. (Val64Met), associated with DEND syndrome, responsive to a combination of super high doses of sulfonylurea (SU) and oral high-dose steroids. A single case was reported so far due to this mutation, presenting with severe DEND syndrome, treated by insulin only. His phenotypic description and management during 18 months, demonstrates this mutation is responsive to super-high doses of SU combined with high dose 6 weeks steroids protocol.

CONCLUSIONS

We have identified a heterozygous missense mutation as the etiology for severe DEND syndrome in a one-day old neonate, presenting with asymptomatic hyperglycemia, responsive to a novel management combination.

Genetic and clinical heterogeneity of permanent neonatal diabetes mellitus: a single tertiary centre experience

AIMS

Neonatal diabetes mellitus (NDM) is a rare disease where diabetes presents during the first six months of life. There are two types of this disorder: permanent neonatal diabetes (PNDM) and transient neonatal diabetes mellitus (TNDM). PNDM occurs due to mutations in genes involved in either beta-cell survival, insulin regulation, and secretion. This study aims to define the genetic aetiology and clinical phenotypes of PNDM in a large Egyptian cohort from a single centre.

METHODS

Patients with PNDM who were diagnosed, treated, or referred for follow-up between January 2002 and January 2021 were identified and clinically phenotyped. All patients were tested for mutations in EIF2AK3, KCNJ11, ABCC8, INS, FOXP3, GATA4, GATA6, GCK, GLIS3, HNF1B, IER3IP1, PDX1, PTF1A, NEUROD1, NEUROG3, NKX2-2, RFX6, SLC2A2, SLC19A2, STAT3, WFS1, ZFP57 using targeted next-generation sequencing (NGS) panel. INSR gene mutation was tested in one patient who showed clinical features of insulin resistance.

RESULTS

Twenty-nine patients from twenty-six families were diagnosed with PNDM. Pathogenic variants were identified in 17/29 patients (59%). EIF2AK3, INS, and K_ATP channel mutations were the commonest causes with frequency of 17%, 17%, and 14%, respectively. Patients with ABBC8 and KCNJ11 mutations were successfully shifted to sulfonylureas (SU). Paired data of glycosylated haemoglobin before and after SU transfer showed improved glycaemic control; 9.6% versus 7.1%, P = 0.041.

CONCLUSIONS

PNDM is a heterogenous disease with variable genotypes and clinical phenotypes among Egyptian patients. EIF2AK3, INS, ABCC8, and KCNJ11 mutations were the commonest causes of PNDM in the study cohort. All patients with K_ATP channel mutations were effectively treated with glyburide, reflecting the fact that genetic testing for patients with NDM is not only important for diagnosis but also for treatment plan and prognosis.

Successful treatment of a cohort of infants with neonatal diabetes using insulin pumps including data on genetics and estimated incidence

AIM

Neonatal diabetes is rare, and treatment is challenging. We present aspects on treatment, genetics and incidence.

METHOD

This was a prospective cohort study including all cases in our study area in Sweden. We compared with data from the National Diabetes Registry, the Neonatal Quality Register and the National Patient Register.

RESULTS

In the 19-year study period January 1, 1998 to December 31, 2016, we treated seven infants, five of them boys. Six patients used a subcutaneous insulin pump, and the smallest patient started at a weight of 938 g. Most important was for the pump to deliver minute doses of insulin and the design of cannulas and tubing. All patients could stop insulin treatment at 17-145 days of age. One patient relapsed at age 4.5 years. Four patients used the insulin pump after discharge. A mutation was identified in five patients, and this included all patients born after 30 weeks of gestation. The incidence of neonatal diabetes was 2/1 00 000, higher than previously estimated for Europe. Similar but lower incidences were reported in the registries.

CONCLUSION

Insulin pumps were safe in neonatal diabetes. All seven cases were transient. Neonatal diabetes was more common in our area than reported from Europe.

Neonatal hyperglycemia in a preterm infant managed with a subcutaneous insulin pump

PURPOSE

Successful use of a subcutaneous insulin pump to administer regular insulin to a preterm infant with neonatal hyperglycemia is described.

SUMMARY

A 520-g female infant born at 23 weeks' gestational age via caesarian section was noted to have elevated blood glucose concentrations ranging up to 180 mg/dL (in SI units, 10 mmol/L) on day of life (DOL) 3 and peaking on DOL 9 at 250 mg/dL (13.9 mmol/L) despite conservative glucose infusion rates. Continuous infusion of regular insulin was begun on DOL 8 and continued through DOL 44, with an average insulin infusion rate of 0.08 units/kg/h. The patient experienced blood glucose concentration lability due to multiple factors, resulting in the need for frequent and routine blood glucose concentration monitoring to minimize hypoglycemia events. On DOL 44, a subcutaneous insulin pump was placed and used to provide diluted regular insulin (25 units/mL). After 1 week, the patient's blood glucose concentration normalized, which led to a reduction in the frequency of glucose monitoring. After 3 weeks, insulin pump use was discontinued. The patient remained euglycemic thereafter.

CONCLUSION

The use of an insulin pump resulted in decreased blood glucose checks, discontinuation of central line access, and overall better patient care.

Congenital diabetes mellitus

Congenital diabetes mellitus is a rare disorder characterized by hyperglycemia that occurs shortly after birth. We define "Diabetes of Infancy" if hyperglycemia onset before 6 months of life. From the clinical point of view, we distinguish two main types of diabetes of infancy: transient (TNDM), which remits spontaneously, and permanent (PNDM), which requires lifelong treatment. TNDM may relapse later in life. About 50% of cases are transient (TNDM) and 50% permanent. Clinical manifestations include severe intrauterine growth retardation, hyperglycemia and dehydration. A wide range of different associated clinical signs including facial dysmorphism, deafness and neurological, cardiac, kidney or urinary tract anomalies are reported. Developmental delay and learning difficulties may also be observed. In this paper we review all the causes of congenital diabetes and all genes and syndromes involved in this pathology. The discovery of the pathogenesis of most forms of congenital diabetes has made it possible to adapt the therapy to the diagnosis and in the forms of alteration of the potassium channels of the pancreatic Beta cells the switch from insulin to glibenclamide per os has greatly improved the quality of life. Congenital diabetes, although it is a very rare form, has been at the must of research in recent years especially for pathogenesis and pharmacogenetics. The most striking difference compared to the more frequent autoimmune diabetes in children (type 1 diabetes) is the possibility of treatment with hypoglycemic agents and the apparent lower frequency of chronic complications.

Diagnosis and management of neonatal diabetes mellitus: A survey of physicians' perceptions and practices in ASPED countries

AIM

To ascertain the awareness and practice of neonatal diabetes mellitus (NDM) among paediatricians in Arab countries.

METHODS

An online questionnaire was distributed to physicians associated with the Arab Society for Paediatric Endocrinology and Diabetes (ASPED).

RESULTS

We received 126 replies, from 16 countries. All except one classified the survey's case scenario as NDM and 94% agreed that NDM patients should have detailed assessment to identify extra-pancreatic features. Although 92% felt that genetic testing is necessary, only 72% requesting them routinely and 32% unaware of the availability of free genetic testing. Insulin is considered the initial therapy for 93% and 80% diluted insulin to deliver accurate doses. Basal-bolus regimen was preferred by 36% and similar percentage used insulin pump. The remaining 28% favour long acting insulin alone. Oral sulfonylureas would be tried empirically by 34% and 69% would do so if genetic testing is unavailable. Whilst 70% have no local NDM management guidelines, 41% are unaware of any international guidelines.

CONCLUSIONS

The ASPED surveyed clinicians have good awareness of NDM diagnosis with marked variation in their practice raising the need to establish management guideline for the condition. The survey highlights areas to focus on in developing consensus and educational activities.

Clinical Characteristics, Molecular Features, and Long-Term Follow-Up of 15 Patients with Neonatal Diabetes: A Single-Centre Experience

BACKGROUND

Diabetes diagnosed within the first 6 months of life is defined as neonatal diabetes mellitus (NDM). Mutations in the KCNJ11, ABCC8, and INS genes are the most common cause of permanent NDM. In populations with a high rate of consanguinity, Wolcott-Rallison syndrome caused by biallelic EIF2AK3 mutations is common.

METHODS

We studied the clinical characteristics and underlying genetic cause of disease in 15 individuals with diabetes onset before 6 months of age as defined by sustained hyperglycaemia requiring insulin treatment. Patients who had a remission of the diabetes, defined by a normal blood glucose and HbA1c value without insulin or sulphonylurea (SU) treatment, within the first 18 months of life were classified as having transient NDM (TNDM).

RESULTS

We report 15 patients with NDM from 14 unrelated families, including 10 with reported parental consanguinity. 1/15 patients had a remission of diabetes, leading to a diagnosis of TNDM. Mutations were detected in 80% (n = 12/15) of the cohort (ABCC8 [n = 4], PTF1A-distal enhancer [n = 3], KCNJ11 [n = 2], EIF2AK3 [n = 1], INS [n = 1], and SLC19A2 [n = 1]). All cases were initially treated with multiple dose insulin injections. One patient with an ABCC8 mutation transitioned from insulin to SU resulting in improved metabolic control at the age of 20 years.

CONCLUSION

Although the number of individuals born to consanguineous parents was considerably high in this cohort, KATP channel mutations (ABCC8/KCNJ11) were more common than EIF2AK3 mutations (n = 6 vs. n = 1). Genetic analyses should be performed in all NDM cases due to the potential impact on treatment and prognosis.

Recent Advances in Neonatal Diabetes

Neonatal diabetes mellitus (DM) is defined by the onset of persistent hyperglycemia within the first six months of life but may present up to 12 months of life. A gene mutation affecting pancreatic beta cells or synthesis/secretion of insulin is present in more than 80% of the children with neonatal diabetes. Neonatal DM can be transient, permanent, or be a component of a syndrome. Genetic testing is important as a specific genetic mutation can significantly alter the treatment and outcome. Patients with mutations of either KCNJ11 or ABCC8 that encode subunits of the K_ATP channel gene mutation can be managed with sulfonylurea oral therapy while patients with other genetic mutations require insulin treatment.

Monogenic diabetes: the impact of making the right diagnosis

PURPOSE OF REVIEW

Monogenic forms of diabetes have received increased attention and genetic testing is more widely available; however, many patients are still misdiagnosed as having type 1 (T1D) or type 2 diabetes. This review will address updates to monogenic diabetes prevalence, identification, treatment, and genetic testing.

RECENT FINDINGS

The creation of a T1D genetic risk score and the use of noninvasive urinary C-peptide creatinine ratios have provided new tools to aid in the discrimination of possible monogenic diabetes from likely T1D. Early, high-dose sulfonylurea treatment in infants with a KCNJ11 or ABCC8 mutation continues to be well tolerated and effective. As the field moves towards more comprehensive genetic testing methods, there is an increased opportunity to identify novel genetic causes. Genetic testing results continue to allow for personalized treatment but should provide patient information at an appropriate health literacy level.

SUMMARY

Although there have been clinical and genetic advances in monogenic diabetes, patients are still misdiagnosed. Improved insurance coverage of genetic testing is needed. The majority of data on monogenic diabetes has been collected from Caucasian populations, therefore, research studies should endeavor to include broader ethnic and racial diversity to provide comprehensive information for all populations.

Genetic causes and treatment of neonatal diabetes and early childhood diabetes

Diabetes mellitus and impaired fasting glucose associated with single gene mutations are less rare than previously thought and may account for more than 6% of patients attending a pediatric diabetes clinic. The number of loci involved in monogenic diabetes exceed 25, and appropriate genetic diagnosis is crucial to direct therapy, for genetic counseling and for prognosis of short- and long-term complications. Among patients with neonatal diabetes (i.e. with onset within first 6 months of life) and patients with Maturity Onset Diabetes of the Young (MODY; an autosomal dominant form of diabetes), those carrying mutations in KCNJ11, ABCC8, HNF1A and HNF4A genes usually respond to oral therapy with sulphonylurea, while those bearing GCK mutations do not necessitate any treatment. Sensor-augmented continuous subcutaneous insulin infusion has been successfully employed in neonatal diabetes, and long-lasting effectiveness of sulfonylurea in KCNJ11 mutation carriers with neonatal diabetes well documented.

Congenital Diabetes: Comprehensive Genetic Testing Allows for Improved Diagnosis and Treatment of Diabetes and Other Associated Features

PURPOSE OF REVIEW

The goal of this review is to provide updates on congenital (neonatal) diabetes from 2011 to present, with an emphasis on publications from 2015 to present.

RECENT FINDINGS

There has been continued worldwide progress in uncovering the genetic causes of diabetes presenting within the first year of life, including the recognition of nine new causes since 2011. Management has continued to be refined based on underlying molecular cause, and longer-term experience has provided better understanding of the effectiveness, safety, and sustainability of treatment. Associated conditions have been further clarified, such as neurodevelopmental delays and pancreatic insufficiency, including a better appreciation for how these "secondary" conditions impact quality of life for patients and their families. While continued research is essential to understand all forms of congenital diabetes, these cases remain a compelling example of personalized genetic medicine.

Congenital forms of diabetes: the beta-cell and beyond

The majority of patients diagnosed with diabetes less than 6 months of age, and many cases diagnosed between 6 and 12 months of age, have a gene mutation that causes permanent or transient hyperglycemia. Recent research advances have allowed for the discovery of new causes of congenital diabetes, including genes involved in pancreatic development (GATA4, NKX2-2, MNX1) and monogenic causes of autoimmune dysregulation (STAT3, LRBA). Ongoing follow-up of patients with KCNJ11 and ABCC8 mutations has supported the safety and efficacy of sulfonylureas, as well as the use of insulin pumps and continuous glucose monitors in infants with insulin-requiring forms of monogenic diabetes. Future studies are needed to improve clinical care and outcomes for these patients and their families.

Transient Neonatal Diabetes Mellitus in a Very Preterm Infant due to ABCC8 Mutation

Neonatal diabetes mellitus (NDM) is a monogenic form of diabetes occurring within 6 months from birth. NDM can be permanent or transient (TNDM). We report the case of a preterm infant with TNDM due to an ABCC8 mutation identified by next-generation sequencing. The pancreatic adenosine triphosphate (ATP)-sensitive K+ (K-ATP) channel is a key regulator of insulin secretion. Gain-of-function mutations in the genes encoding the Kir6.2 (KCNJ11) and SUR1 (ABCC8) subunits of the channel cause neonatal diabetes. The patient was successfully managed with insulin lispro at a 1:100 dilution, drawn up in an insulin pen injector with a 4-mm needle. The insulin lispro dilution allowed administration of the exact insulin doses, obtaining a good glycemic control and minimizing the burden of injections. At 2 months, corrected age insulin doses were progressively decreased until discontinuation.