Quality of Life and Treatment Satisfaction in Participants with Maturity-Onset Diabetes of the Young: A Comparison to Other Major Forms of Diabetes.

AIMS: We investigated the quality of life (QoL), treatment satisfaction and perception of genetic results in participants with Maturity-Onset Diabetes of the Young (MODY) and compared the results with those of subjects with type 1 (T1D) or type 2 (T2D) diabetes. METHODS: A total of 162 adults with GCK-MODY, 62 with HNF1A-MODY and 29 with HNF4A-MODY answered the questionnaire Audit of Diabetes Dependent Quality of Life, the Diabetes Treatment Satisfaction Questionnaire and non-validated instrument examining the respondent's perception of the genetic results. Data from GCK-MODY patients were compared with 84 participants with T2D and HNF-MODY subjects were compared with 81 participants having T1D. RESULTS: Higher age (p=0.004), higher haemoglobin A1c (p=0.026) and medication (p=0.019) were associated with lower general QoL in GCK-MODY patients. In HNF-MODY patients, lower general QoL was associated with a longer time since diagnosis (p=0.005), worse haemoglobin bA1c (p=0.006) and insulin treatment (p=0.019). Similar numbers of participants with GCK- and HNF-MODY considered the genetic diagnosis of MODY to be positive, negative and without significance. The patient with GCK-MODY did not differ from those with T2D in terms of their QoL, but they were less satisfied with their treatment (p<0.001). QoL was better in patients with HNF-MODY compared with patients with T1D (p=0.006), and they did not differ in terms of treatment satisfaction. CONCLUSIONS: QoL was affected in both GCK-MODY and HNF-MODY subjects. Apprehension of genetic diagnosis was not single-valued in MODY respondents.

Congenital Hyperinsulinism Caused by Novel Homozygous KATP Channel Gene Variants May Be Linked to Unexplained Neonatal Deaths among Kurdish Consanguineous Families.

INTRODUCTION: Neonatal hypoglycemia due to congenital hyperinsulinism (CHI) is a potentially life-threatening condition. Biallelic pathogenic variants in KATP channel subunit genes (ABCC8, KCNJ11), causing severe forms of CHI, are more prevalent in regions with a significant rate of consanguinity and may lead to unexplained neonatal deaths. We hypothesized that KATP channel gene variants are the cause of CHI in three unrelated children from consanguineous Kurdish families with histories of four unexplained neonatal deaths with convulsions. CASES: (1) A girl presented on the 6th day of life with recurrent hypoglycemic convulsions (blood glucose 2.05 mmol/L, insulin 58 mIU/L, C-peptide 2,242 pmol/L). (2) A girl with severe developmental delay was diagnosed with CHI at 3 years of age (blood glucose 2.78 mmol/L, insulin 8.1 mIU/L, C-peptide 761 pmol/L) despite a history of recurrent hypoglycemia since neonatal age. (3) A girl presented at 3 weeks of age with convulsions and unconsciousness (blood glucose 2.5 mmol/L, insulin 14.6 mIU/L, C-peptide 523 pmol/L). Coding regions of the ABCC8 and KCNJ11 genes were tested by Sanger sequencing. Potential variants were evaluated using the American College of Medical Genetics standards. Three novel causative homozygous variants were found - p.Trp514Ter in the ABCC8 gene (Pt2), and p.Met1Val (Pt1) and p.Tyr26Ter (Pt3) in the KCNJ11 gene. CONCLUSION: CHI caused by KATP channel variants was elucidated in three children, providing a highly probable retrospective diagnosis for their deceased siblings. Future lives can be saved by timely diagnosis of CHI when encountering a neonate with unexplained seizures or other signs of recurrent and/or persistent hypoglycemia.

Effectiveness and safety of the tri-iodothyronine analogue Triac in children and adults with MCT8 deficiency: an international, single-arm, open-label, phase 2 trial.

BACKGROUND: Deficiency of the thyroid hormone transporter monocarboxylate transporter 8 (MCT8) causes severe intellectual and motor disability and high serum tri-iodothyronine (T3) concentrations (Allan-Herndon-Dudley syndrome). This chronic thyrotoxicosis leads to progressive deterioration in bodyweight, tachycardia, and muscle wasting, predisposing affected individuals to substantial morbidity and mortality. Treatment that safely alleviates peripheral thyrotoxicosis and reverses cerebral hypothyroidism is not yet available. We aimed to investigate the effects of treatment with the T3 analogue Triac (3,3',5-tri-iodothyroacetic acid, or tiratricol), in patients with MCT8 deficiency. METHODS: In this investigator-initiated, multicentre, open-label, single-arm, phase 2, pragmatic trial, we investigated the effectiveness and safety of oral Triac in male paediatric and adult patients with MCT8 deficiency in eight countries in Europe and one site in South Africa. Triac was administered in a predefined escalating dose schedule-after the initial dose of once-daily 350 µg Triac, the daily dose was increased progressively in 350 µg increments, with the goal of attaining serum total T3 concentrations within the target range of 1·4-2·5 nmol/L. We assessed changes in several clinical and biochemical signs of hyperthyroidism between baseline and 12 months of treatment. The prespecified primary endpoint was the change in serum T3 concentrations from baseline to month 12. The co-primary endpoints were changes in concentrations of serum thyroid-stimulating hormone (TSH), free and total thyroxine (T4), and total reverse T3 from baseline to month 12. These analyses were done in patients who received at least one dose of Triac and had at least one post-baseline evaluation of serum throid function. This trial is registered with ClinicalTrials.gov, number NCT02060474. FINDINGS: Between Oct 15, 2014, and June 1, 2017, we screened 50 patients, all of whom were eligible. Of these patients, four (8%) patients decided not to participate because of travel commitments. 46 (92%) patients were therefore enrolled in the trial to receive Triac (median age 7·1 years [range 0·8-66·8]). 45 (98%) participants received Triac and had at least one follow-up measurement of thyroid function and thus were included in the analyses of the primary endpoints. Of these 45 patients, five did not complete the trial (two patients withdrew [travel burden, severe pre-existing comorbidity], one was lost to follow-up, one developed of Graves disease, and one died of sepsis). Patients required a mean dose of 38.3 µg/kg of bodyweight (range 6·4-84·3) to attain T3 concentrations within the target range. Serum T3 concentration decreased from 4·97 nmol/L (SD 1·55) at baseline to 1·82 nmol/L (0·69) at month 12 (mean decrease 3·15 nmol/L, 95% CI 2·68-3·62; p<0·0001), while serum TSH concentrations decreased from 2·91 mU/L (SD 1·68) to 1·02 mU/L (1·14; mean decrease 1·89 mU/L, 1·39-2·39; p<0·0001) and serum free T4 concentrations decreased from 9·5 pmol/L (SD 2·5) to 3·4 (1·6; mean decrease 6·1 pmol/L (5·4-6·8; p<0·0001). Additionally, serum total T4 concentrations decreased by 31·6 nmol/L (28·0-35·2; p<0·0001) and reverse T3 by 0·08 nmol/L (0·05-0·10; p<0·0001). Seven treatment-related adverse events (transiently increased perspiration or irritability) occurred in six (13%) patients. 26 serious adverse events that were considered unrelated to treatment occurred in 18 (39%) patients (mostly hospital admissions because of infections). One patient died from pulmonary sepsis leading to multi-organ failure, which was unrelated to Triac treatment. INTERPRETATION: Key features of peripheral thyrotoxicosis were alleviated in paediatric and adult patients with MCT8 deficiency who were treated with Triac. Triac seems a reasonable treatment strategy to ameliorate the consequences of untreated peripheral thyrotoxicosis in patients with MCT8 deficiency. FUNDING: Dutch Scientific Organization, Sherman Foundation, NeMO Foundation, Wellcome Trust, UK National Institute for Health Research Cambridge Biomedical Centre, Toulouse University Hospital, and Una Vita Rara ONLUS.

Could a combination of heterozygous ABCC8 and KCNJ11 mutations cause congenital hyperinsulinism?

BACKGROUND: Congenital hyperinsulinism (CHI) is frequently caused by mutations in one of the KATP channel subunits encoded by the genes ABCC8 and KCNJ11. The effect of simultaneous mutations in both of these genes on the pancreatic ß-cell function is not known and patients with CHI carrying both ABCC8 and KCNJ11 mutations have not yet been reported. We questioned if a combination of heterozygous mutations in the ABCC8 and KCNJ11 genes could also lead to ß-cell dysfunction presenting as CHI. METHODS: As a model, we used a patient with transient CHI that paternally inherited novel heterozygous mutations in ABCC8 (p.Tyr1293Asp) and KCNJ11 (p.Arg50Trp) genes. The pathogenic effects on the pancreatic ß-cells function were examined in an in vitro functional study using radioactive rubidium efflux assay. RESULTS: We showed that the activation of the mutated KATP channels by diazoxide was decreased by 60.9% in the channels with the heterozygous combination of both mutations compared to the wild type channels. This could indicate the pathogenic effect on the pancreatic ß-cell function leading to CHI although conclusive evidence is needed to be added. CONCLUSIONS: Our findings may widen the spectrum of genetic causes of CHI and suggest a novel pathogenic mechanism of CHI that must however, be further investigated.

[Congenital hyperinsulinism: Loss of B-cell self-control]. / Vrozený hyperinzulinizmus: kdyz B-bunka ztratí sebekontrolu.

Congenital hyperinsulinism is a serious blood glucose regulation defect that interferes with brain development, leading to mental retardation, neurological sequelae and secondary epilepsy and ultimately may be life-threatening. Congenital hyperinsulinism (CHI) is caused by genetic defects of regulation of insulin secretion that induce insulin oversecretion in intrauterine life and postnatally. The clinical consequence is fetal macrosomia and subsequently neonatal and infantile hypoglycaemia. The most severe form is caused by biallelic mutations of KCNJ11 and ABCC8 genes that encode both potassium channel subunits, whereas their heterozygous mutations as well as enzymatic defects (GLUD1, HADH, GCK) lead to milder presentation. HNF4A or HNF1A transcriptional factor defects lead to transient hyperinsulinism but to MODY diabetes later in life, due to biphasic beta-cell dysfunction starting as hyperfunction and developing via normal function to hypofunction. An early aetiological diagnosis and effective treatment of congenital hyperinsulinism substantially improves the outcome regarding not only survival but also neurocognitive functions.Key words: B-cell - congenital hyperinsulinism (CHI) - hypoglycaemia - insulin.

Severe Hyperinsulinaemic Hypoglycaemia in Beckwith-Wiedemann Syndrome due to Paternal Uniparental Disomy of 11p15.5 Managed with Sirolimus Therapy.

BACKGROUND: Almost half of the children with Beckwith-Wiedemann syndrome (BWS) will develop hyperinsulinaemic hypoglycaemia (HH). In the majority of BWS cases, HH will be transient; however, approximately in 5% of them, HH will be severe and often medically-unresponsive. Children with BWS due to paternal uniparental disomy (UPD) of chromosome 11p15 belong to this severe category and have traditionally required near-total pancreatectomy. The use of mTOR inhibitors had not been reported yet in this type of patients. CASE: A 1-month-old female with genetically confirmed BWS due to UPD of chromosome 11p15 was admitted for management of severe HH. Blood glucose concentrations were stabilised with high intravenous dextrose concentration, glucagon and octreotide infusions as she was proven to be diazoxide unresponsive. To avoid a subtotal pancreatectomy, an mTOR inhibitor - sirolimus - was introduced. The dose of sirolimus was optimised progressively and she was able to come off intravenous fluids and glucagon therapy. She has not presented any side effects and her growth is normal after 19 months of therapy. CONCLUSION: This is the first case reported of BWS due to UPD of chromosome 11p15 where sirolimus treatment has been effective in stabilising the blood glucose concentrations and avoiding a near-total pancreatectomy without major side effects detected.

High Incidence of Heterozygous ABCC8 and HNF1A Mutations in Czech Patients With Congenital Hyperinsulinism.

CONTEXT: Congenital hyperinsulinism of infancy (CHI) represents a group of heterogeneous disorders characterized by oversecretion of insulin from pancreatic ß-cells causing severe hypoglycemia. OBJECTIVE: We studied the distribution of genetic causes of CHI in a Czech population. METHODS: Countrywide collection of patients with CHI included 40 subjects (12 females, median age of diagnosis, 1 wk [interquartile range, 1-612 wk]). We sequenced the ABCC8, KCNJ11, GLUD1, GCK, HADH, UCP2, SLC16A1, HNF4A, and HNF1A genes and investigated structural changes in the ABCC8 gene. We functionally tested novel variants in the ABCC8 gene by Rb(86+) efflux assay and novel variants in the HNF1A gene by transcriptional activation and DNA-binding tests. RESULTS: We found causal mutations in 20 subjects (50%): 19 carried a heterozygous mutation while one patient was homozygous for mutation in the ABCC8 gene. Specifically, we detected 11 mutations (seven novel) in ABCC8, one novel mutation in KCNJ11, five mutations (two novel) in HNF1A, two novel mutations in HNF4A, and one in GCK. We showed a decrease of activation by diazoxide in mutant KATP channels with novel ABCC8 variants by 41-91% (median, 82%) compared with wild-type (WT) channels and reduced transcriptional activity of mutant HNF1A proteins (2.9% for p.Asn62Lysfs93* and 22% for p.Leu254Gln) accompanied by no DNA-binding ability compared with WT HNF1A. CONCLUSION: We detected a higher proportion of heterozygous mutations causing CHI compared with other cohorts probably due to lack of consanguinity and inclusion of milder CHI forms. Interestingly, HNF1A gene mutations represented the second most frequent genetic cause of CHI in the Czech Republic. Based on our results we present a genetic testing strategy specific for similar populations.

The Diagnosis and Management of Hyperinsulinaemic Hypoglycaemia.

Insulin secretion from pancreatic ß-cells is tightly regulated to keep fasting blood glucose concentrations within the normal range (3.5-5.5 mmol/L). Hyperinsulinaemic hypoglycaemia (HH) is a heterozygous condition in which insulin secretion becomes unregulated and its production persists despite low blood glucose levels. It is the most common cause of severe and persistent hypoglycaemia in neonates and children. The most severe and permanent forms are due to congenital hyperinsulinism (CHI). Recent advances in genetics have linked CHI to mutations in 9 genes that play a key role in regulating insulin secretion (ABCC8, KCNJ11, GLUD1, GCK, HADH, SLC16A1, UCP2, HNF4A and HNF1A). Histologically, CHI can be divided into 3 types; diffuse, focal and atypical. Given the biochemical nature of HH (non-ketotic), a delay in the diagnosis and management can result in irreversible brain damage. Therefore, it is essential to diagnose and treat HH promptly. Advances in molecular genetics, imaging methods (18F-DOPA PET-CT), medical therapy and surgical approach (laparoscopic surgery) have completely changed the management and improved the outcome of these children. This review provides an overview of the genetic and molecular mechanisms leading to development of HH in children. The article summarizes the current diagnostic methods and management strategies for the different types of CHI.