Permanent neonatal diabetes mellitus (PNDM) is a rare form of diabetes characterized by insulin-requiring hyperglycemia that is diagnosed within the first months of life. Recently, activating mutations in the gene encoding the ATP-sensitive potassium-channel subunit Kir6.2 were identified in 10 PNDM patients. Tolbutamide-stimulated insulin secretion, demonstrated in 3 of these patients suggested that some PNDM patients may respond to oral sulfonylurea treatment. In this report, we describe an infant with PNDM due to an arginine-to-histidine substitution at position 201 (R201H) of the gene encoding Kir6.2. After insulin pump therapy for six months, he was shifted to oral glybenclamide therapy at a daily dose of 0.8 mg/kg. Basal c-peptide level increased by two fold during glybenclamide treatment, but no further elevation was observed following intravenous glucose administration. Outpatient, continuous glucose monitoring while on a normal infant diet demonstrated a marked improvement in glycemic control. This study demonstrates the feasibility of oral sulfonylurea treatment in PNDM patients with Kir6.2 mutations even during infancy, and the superiority of this approach over insulin administration.

In this pilot trial, continuous subcutaneous glucose monitoring was helpful in detecting asymptomatic nocturnal hypoglycemia as well as in lowering HbA1c values without increasing the risk for severe hypoglycemia in children with type 1 diabetes.

Background: Disordered thyroid hormone transport, due to mutations in the SLC16A2 gene encoding monocarboxylate transporter 8 (MCT8), is characterised by intellectual and motor disability resulting from cerebral hypothyroidism and chronic peripheral thyrotoxicosis. We sought to systematically assess the phenotypic characteristics and natural history of patients with MCT8 deficiency. Methods: We did an international, multicentre, cohort study, analysing retrospective data from Jan 1, 2003, to Dec 31, 2019, from patients with MCT8 deficiency followed up in 47 hospitals in 22 countries globally. The key inclusion criterion was genetically confirmed MCT8 deficiency. There were no exclusion criteria. Our primary objective was to analyse the overall survival of patients with MCT8 deficiency and document causes of death. We also compared survival between patients who did or did not attain full head control by age 1•5 years and between patients who were or were not underweight by age 1-3 years (defined as a bodyweight-for-age Z score <-2 SDs or <5th percentile according to WHO definition). Other objectives were to assess neurocognitive function and outcomes, and clinical parameters including anthropometric characteristics, biochemical markers, and neuroimaging findings. Findings: Between Oct 14, 2014, and Jan 17, 2020, we enrolled 151 patients with 73 different MCT8 (SLC16A2) mutations. Median age at diagnosis was 24•0 months (IQR 12•0-60•0, range 0•0-744•0). 32 (21%) of 151 patients died; the main causes of mortality in these patients were pulmonary infection (six [19%]) and sudden death (six [19%]). Median overall survival was 35•0 years (95% CI 8•3-61•7). Individuals who did not attain head control by age 1•5 years had an increased risk of death compared with patients who did attain head control (hazard ratio [HR] 3•46, 95% CI 1•76-8•34; log-rank test p=0•0041). Patients who were underweight during age 1-3 years had an increased risk for death compared with patients who were of normal bodyweight at this age (HR 4•71, 95% CI 1•26-17•58, p=0•021). The few motor and cognitive abilities of patients did not improve with age, as evidenced by the absence of significant correlations between biological age and scores on the Gross Motor Function Measure-88 and Bayley Scales of Infant Development III. Tri-iodothyronine concentrations were above the age-specific upper limit in 96 (95%) of 101 patients and free thyroxine concentrations were below the age-specific lower limit in 94 (89%) of 106 patients. 59 (71%) of 83 patients were underweight. 25 (53%) of 47 patients had elevated systolic blood pressure above the 90th percentile, 34 (76%) of 45 patients had premature atrial contractions, and 20 (31%) of 64 had resting tachycardia. The most consistent MRI finding was a global delay in myelination, which occurred in 13 (100%) of 13 patients. Interpretation: Our description of characteristics of MCT8 deficiency in a large patient cohort reveals poor survival with a high prevalence of treatable underlying risk factors, and provides ...

Xenotransplantation of pig tissues has great potential to overcome the shortage of organ donors. One approach to address the vigorous immune rejection associated with xenotransplants is the use of embryonic precursor tissue, which induces and utilizes host vasculature upon its growth and development. Recently, we showed in mice that embryonic pig pancreatic tissue from embryonic day 42 (E42) exhibits optimal properties as a ␤ cell replacement therapy. We now demonstrate the proof of concept in 2 diabetic Cynomolgus monkeys, followed for 393 and 280 days, respectively. A marked reduction of exogenous insulin requirement was noted by the fourth month after transplantation, reaching complete independence from exogenous insulin during the fifth month after transplantation, with full physiological control of blood glucose levels. The porcine origin of insulin was documented by a radioimmunoassay specific for porcine C-peptide. Furthermore, the growing tissue was found to be predominantly vascularized with host blood vessels, thereby evading hyperacute or acute rejection, which could potentially be mediated by preexisting anti-pig antibodies. Durable graft protection was achieved, and most of the late complications could be attributed to the immunosuppressive protocol. While fine tuning of immune suppression, tissue dose, and implantation techniques are still required, our results demonstrate that porcine E-42 embryonic pancreatic tissue can normalize blood glucose levels in primates. Its long-term proliferative capacity, its revascularization by host endothelium, and its reduced immunogenicity, strongly suggest that this approach could offer an attractive replacement therapy for diabetes.immune-suppression ͉ rejection ͉ xeno-transplantation

Two recent reports describe a new syndrome of intellectual disability, short stature, microcephaly, and young onset diabetes or disturbed glucose metabolism in association with inactivating mutations in the TRMT10A gene. We investigated the clinical spectrum presented by a 17-year-old female with a homozygous contiguous gene deletion involving the TRMT10A gene. From infancy, she presented with failure to thrive and microcephaly. Puberty was characterized by a slow and an inconsistent course of progression. Concomitantly, gonadotropin levels fluctuated between low and high levels which were compatible with gonadal failure. Unlike the previous reports, the patient had ketoacidosis at onset of diabetes and islet cell autoantibodies. Nevertheless, glycemic control was excellent (HbA1C 5.0%-6.2%). RT-PCR and Western blot analysis demonstrated a complete abolishment of TRMT10A mRNA and its translated protein. In order to elucidate the nature of diabetes in this patient, endogenous insulin secretion and glycemic control were evaluated by a glucagon stimulation test and continuous glucose monitoring both during insulin treatment and off therapy. Endogenous insulin secretion still persisted 22 months after onset of diabetes and relatively normal glucose levels were kept over 3 days without insulin treatment. The fluctuating course of puberty and diabetes may reflect intermittent apoptotic damages due to sensitization of the relevant cells to various stress agents in the absence of functional TRMT10A.

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Objective: The monocarboxylate transporter 8 (MCT8; SLC16A2) has a pivotal role in neuronal triiodothyronine (T 3 ) uptake. Mutations of this transporter determine a distinct X-linked psychomotor retardation syndrome (Allan-Herndon-Dudley syndrome (AHDS)) that is attributed to disturbed thyroid hormone levels, especially elevated T 3 levels. We describe the genetic analysis of the MCT8 gene in a patient suspected for AHDS and the clinical and endocrine effects of L-thyroxine (LT 4 ) or liothyronine (LT 3 ) treatment intending to overcome the T 3 uptake resistance through alternative transporters. Methods: The six exons of the MCT8 gene were amplified individually by PCR. As multiple exons were missing, the length of the X-chromosomal deletion was determined by a dense SNP array, followed by PCR-based fine mapping to define the exact borders of the deleted segment. The clinical and endocrine data of the patient during 6.5 years of LT 4 treatment and two periods (3 months each) of low-and high-dose LT 3 were evaluated. Results: A partial deletion of the MCT8 gene (comprising five of six exons) was detected, confirming the suspected AHDS. MCT8 dysfunction was associated with partial resistance to T 3 at the hypothalamus and pituitary level, with normal responsiveness at the peripheral organs (liver and cardiovascular system). Thyroid hormone administration had no beneficial effect on the neurological status of the patient. Conclusion: We identified a 70 kb deletion encompassing exons 2-6 of the MCT8 gene in our AHDS patient. Both LT 4 and LT 3 administration had no therapeutic effect. Alternatively, treatment of AHDS patients with thyroid hormone analogs should be considered.

We recommend obtaining thyroid imaging to distinguish between the two forms of HT. Adherence to recommended doses of thyroxine and probably early cessation of therapy in transient HT can prevent iatrogenic hyperthyroidism in these patients.