Insulin Autoimmune Syndrome - An After-Meal Roller Coaster Ride.

Hypoglycemic disorders are rare in persons without diabetes, and clinical evaluation to identify its etiology can be challenging. We present a case of insulin autoimmune syndrome induced by carbimazole in a middle-aged Chinese man with underlying Graves' disease, which was managed conservatively with a combination of dietary modification and alpha-glucosidase inhibitor.

Cardiometabolic Risk Assessment in a Cohort of Children and Adolescents Diagnosed with Hyperinsulinemia.

BACKGROUND: Individuals with hyperinsulinemia may initially not meet any diagnostic criteria for metabolic syndrome, though displaying a higher risk of cardiovascular complications combined with obesity, diabetes, and hypertension. AIM: The main objective of our study was to assess the diagnostic accuracy of various cardiovascular risk indices in hyperinsulinemic children and adolescents; a secondary objective was to estimate the optimal cut-offs of these indices. PATIENTS AND METHODS: This retrospective single-center study was conducted on 139 patients aged 12.1 ± 2.9 years, managed for hyperinsulinism. RESULTS: We found statistically significant differences in homeostasis model assessment of insulin resistance index (HOMA-IR), triglyceride glucose index (TyG), TyG-body mass index, visceral adiposity index, lipid accumulation product index, fatty liver index, and hepatic steatosis index. At the linear logistic regression assessment, we found that insulin growth factor-1 (IGF-1), HOMA-IR, and ALT/AST ratio were independently associated with confirmed hyperinsulinism. At the multivariate analysis, IGF-1 levels over 203 ng/mL and HOMA-IR higher than 6.2 were respectively associated with a 9- and 18-times higher odds ratio for hyperinsulinism. The other investigated parameters were not significantly related to hyperinsulinism, and could not predict either the presence of hyperinsulinemia or a subsequent cardiovascular risk in our patients. CONCLUSION: Commonly used indices of cardiovascular risk in adults cannot be considered accurate in confirming hyperinsulinism in children, with the exception of HOMA-IR. Further studies are needed to verify the usefulness of specific cardiovascular risk indices in hyperinsulinemic children and adolescents.

Transient Neonatal Hypocortisolism in Neonates with Hypoglycemia - Coexistence or Cause?

Introduction: Infants born preterm, with low birth weight (LBW), or with perinatal stress are at high risk for neonatal hypoglycemia. Low cortisol levels have also been demonstrated in this group of neonates, which is often transient. We report a series of neonates with transient hypocortisolism who had neonatal hypoglycemia. Methods: A descriptive study on clinic-biochemical parameters of a group of five neonates who had persistent neonatal hypoglycemia and had demonstrated low cortisol on critical sample testing. Results: All five neonates had birth weights below normal and four were born preterm. A history of perinatal asphyxia was seen in four cases and neonatal sepsis in two. During critical sample testing (when blood glucose [BG] was <50 mg/dl), hyperinsulinism (Insulin >2 mIU/ml) was seen in three infants whereas insulin was undetectable in two. The median cortisol during critical sample testing was 1.9 mcg/dl (0.88 - 3.7). Critical GH was normal in all, and ACTH ranged from 7.2 pg/ml to 41.3 pg/ml. None of the infants had overt clinical features of panhypopituitarism or primary adrenal insufficiency. USG brain revealed germinal matrix hemorrhage in two infants, which resolved on follow-up. USG adrenals and electrolytes were normal in all. Four of the five babies were started on oral hydrocortisone, to which they responded well with the resolution of hypoglycemia. No adverse events were noted. On follow-up, the median time to recover of serum cortisol to normal was 4 months. Conclusion: The contribution of transient hypocortisolism to hypoglycemia in infants at risk, including preterm, LBW, or those with perinatal stress, in the presence or absence of hyperinsulinism, is not well known. While the non-specific use of glucocorticoids is not advocated, the role of therapeutic glucocorticoids among at-risk neonates with documented hypocortisolism during hypoglycemia should be an area for research. Close follow-up of these neonates for spontaneous recovery of cortisol levels is warranted.

Non-invasive quantification of stem cell-derived islet graft size and composition.

AIMS/HYPOTHESIS: Stem cell-derived islets (SC-islets) are being used as cell replacement therapy for insulin-dependent diabetes. Non-invasive long-term monitoring methods for SC-islet grafts, which are needed to detect misguided differentiation in vivo and to optimise their therapeutic effectiveness, are lacking. Positron emission tomography (PET) has been used to monitor transplanted primary islets. We therefore aimed to apply PET as a non-invasive monitoring method for SC-islet grafts. METHODS: We implanted different doses of human SC-islets, SC-islets derived using an older protocol or a state-of-the-art protocol and SC-islets genetically rendered hyper- or hypoactive into mouse calf muscle to yield different kinds of grafts. We followed the grafts with PET using two tracers, glucagon-like peptide 1 receptor-binding [18F]F-dibenzocyclooctyne-exendin-4 ([18F]exendin) and the dopamine precursor 6-[18F]fluoro-L-3,4-dihydroxyphenylalanine ([18F]FDOPA), for 5 months, followed by histological assessment of graft size and composition. Additionally, we implanted a kidney subcapsular cohort with different SC-islet doses to assess the connection between C-peptide and stem cell-derived beta cell (SC-beta cell) mass. RESULTS: Small but pure and large but impure grafts were derived from SC-islets. PET imaging allowed detection of SC-islet grafts even <1 mm3 in size, [18F]exendin having a better detection rate than [18F]FDOPA (69% vs 44%, <1 mm3; 96% vs 85%, >1 mm3). Graft volume quantified with [18F]exendin (r2=0.91) and [18F]FDOPA (r2=0.86) strongly correlated with actual graft volume. [18F]exendin PET delineated large cystic structures and its uptake correlated with graft SC-beta cell proportion (r2=0.68). The performance of neither tracer was affected by SC-islet graft hyper- or hypoactivity. C-peptide measurements under fasted or glucose-stimulated conditions did not correlate with SC-islet graft volume or SC-beta cell mass, with C-peptide under hypoglycaemia having a weak correlation with SC-beta cell mass (r2=0.52). CONCLUSIONS/INTERPRETATION: [18F]exendin and [18F]FDOPA PET enable non-invasive assessment of SC-islet graft size and aspects of graft composition. These methods could be leveraged for optimising SC-islet cell replacement therapy in diabetes.

"An unprecedented occurrence: a case report of pulmonary hypertension manifestation in Donohue syndrome".

INTRODUCTION: Donohue syndrome (DS), also referred to as leprechaunism, is a remarkably uncommon autosomal recessive disorder that primarily affects the endocrine system. Its incidence rate is exceedingly low, with only 1 case reported per 4 million live births. The syndrome is distinguished by a series of characteristic clinical features. CASE PRESENTATION: We present a case of a twenty-month-old male with DS who experienced a range of dysmorphic and clinical features with the involvement of multiple systems. These features include skin hyperpigmentation, hypertrichosis, distinct facial features, abdominal distension, and microcephaly, with the involvement of the endocrine, renal, respiratory, and cardiac systems. CONCLUSION: The primary features of DS involve severe insulin resistance and growth abnormalities, the association with pulmonary hypertension (PHTN) has not been reported before. This finding adds more complexity to the condition. To the best of the author's knowledge, this is the first report for a patient with DS who has PHTN. Further investigation is required since the mechanisms behind the development of PHTN in DS are not entirely understood. Shedding light on this association will contribute to better management strategies and outcomes for affected patients.

Congenital Hyperinsulinism of a Large Italian Cohort: A Retrospective Study.

INTRODUCTION: To evaluate and describe the diagnostic process, medical, nutritional, and surgical approach, and neurological outcome, we report data from a large Italian cohort of patients with congenital hyperinsulinism (CHI). METHODS: We retrospectively analyzed 154 CHI patients admitted to Ospedale Pediatrico Bambino Gesù from 1985 to 2022. RESULTS: Hypoglycemia occurred within the first year of life in 85.5% of patients, median time to diagnosis was 1 day (IQR 14 days). Ninety-two percent of patients were treated with diazoxide: 66.9% were responsive. Octreotide was administered to 28.6% of patients: 61.4% were responsive. Forty percent of patients were off-therapy, mostly from diazoxide. Thirty-four percent of patients carried mutations in ABCC8, 12.6% were syndromic, and 9.2% were transient CHI. Surgery was performed in 23/47 diazoxide-unresponsive and 2/95 diazoxide-responsive patients: 64.0% were focal at histology. Combining data from genetics, pancreatic venous sampling, 18F-DOPA PET/CT, and histology, 80.6% resulted diffuse, 16.7% focal, and 2.8% atypical CHI. Post-surgical diabetes developed in 6 patients. Neurocognitive evaluation revealed developmental delay or intellectual disability in 15.7% of 70 patients, mostly of a mild degree. Epilepsy was documented in 13.7% of 139 patients. CONCLUSION: Our diagnostic and therapeutic results are mainly consistent with the international indications and the CHI Global Registry data, with relatively low rates of neurological outcomes. Good outcomes were likely associated with early diagnosis and prompt management of patients because the majority of patients were diagnosed within 2 weeks. Remarkably, it is of utmost importance to spread the knowledge and refer CHI patients to multidisciplinary expert centers.

Proposed Screening for Congenital Hyperinsulinism in Newborns: Perspective from a Neonatal-Perinatal Medicine Group.

This perspective work by academic neonatal providers is written specifically for the audience of newborn care providers and neonatologists involved in neonatal hypoglycemia screening. Herein, we propose adding a screen for congenital hyperinsulinism (CHI) by measuring glucose and ketone (i.e., ß-hydroxybutyrate (BOHB)) concentrations just prior to newborn hospital discharge and as close to 48 h after birth as possible, at the same time that the mandated state Newborn Dried Blood Spot Screen is obtained. In the proposed protocol, we do not recommend specific metabolite cutoffs, as our primary objective is to simply highlight the concept of screening for CHI in newborns to newborn caregivers. The premise for our proposed screen is based on the known effect of hyperinsulinism in suppressing ketogenesis, thereby limiting ketone production. We will briefly discuss genetic CHI, other forms of neonatal hypoglycemia, and their shared mechanisms; the mechanism of insulin regulation by functional pancreatic islet cell membrane KATP channels; adverse neurodevelopmental sequelae and brain injury due to missing or delaying the CHI diagnosis; the principles of a good screening test; how current neonatal hypoglycemia screening programs do not fulfill the criteria for being effective screening tests; and our proposed algorithm for screening for CHI in newborns.

Approach to the Neonate with Hypoglycemia.

After birth, healthy neonates undergo a period of altered glucose metabolism, known as "transitional hypoglycemia". During the first 0-4 hours of life, the mean plasma glucose concentration decreases to 57 mg/dL, then by 72-96 hours of life increases to 82 mg/dL, well within the normal adult range. Recent data suggests that transitional hypoglycemia is due to persistence of the fetal beta cell's lower threshold for insulin release, resulting in a transient hyperinsulinemic state. While hypoglycemia is an expected part of the transition to postnatal life, it makes the identification of infants with persistent hypoglycemia disorders challenging. Given the risk of neurologic injury from hypoglycemia, identifying these infants is critical. Hyperinsulinism is the most common cause of persistent hypoglycemia in neonates and infants and carries a high risk of neurocognitive dysfunction given the severity of the hypoglycemia and the inability to generate ketones, a critical alternative cerebral fuel. Screening neonates at risk for persistent hypoglycemia disorders and completing evaluations prior to hospital discharge is essential to prevent delayed diagnoses and neurologic damage.

First Accuracy and User-Experience Evaluation of New Continuous Glucose Monitoring System for Hypoglycemia Due to Hyperinsulinism.

INTRODUCTION: Patients with congenital hyperinsulinism (HI) require constant glucose monitoring to detect and treat recurrent and severe hypoglycemia. Historically, this has been achieved with intermittent self-monitoring blood glucose (SMBG), but patients are increasingly using continuous glucose monitoring (CGM). Given the rapidity of CGM device development, and increasing calls for CGM use from HI families, it is vital that new devices are evaluated early. METHODS: We provided two months of supplies for the new Dexcom G7 CGM device to 10 patients with HI who had recently finished using the Dexcom G6. Self-monitoring blood glucose was performed concurrently with paired readings providing accuracy calculations. Patients and families completed questionnaires about device use at the end of the two-month study period. RESULTS: Compared to the G6, the G7 showed a significant reduction in mean absolute relative difference (25%-18%, P < .001) and in the over-read error (Bland Altman +1.96 SD; 3.54 mmol/L to 2.95 mmol/L). This resulted in an improvement in hypoglycemia detection from 42% to 62% (P < .001). Families reported an overall preference for the G7 but highlighted concerns about high sensor failure rates. DISCUSSION: The reduction in mean absolute relative difference and over-read error and the improvement in hypoglycemia detection implies that the G7 is a safer and more useful device in the management of hypoglycemia for patients with HI. Accuracy, while improved from previous devices, remains suboptimal with 40% of hypoglycemia episodes not detected.

Evolutionary Changes in Primate Glutamate Dehydrogenases 1 and 2 Influence the Protein Regulation by Ligands, Targeting and Posttranslational Modifications.

There are two paralogs of glutamate dehydrogenase (GDH) in humans encoded by the GLUD1 and GLUD2 genes as a result of a recent retroposition during the evolution of primates. The two human GDHs possess significantly different regulation by allosteric ligands, which is not fully characterized at the structural level. Recent advances in identification of the GDH ligand binding sites provide a deeper perspective on the significance of the accumulated substitutions within the two GDH paralogs. In this review, we describe the evolution of GLUD1 and GLUD2 after the duplication event in primates using the accumulated sequencing and structural data. A new gibbon GLUD2 sequence questions the indispensability of ancestral R496S and G509A mutations for GLUD2 irresponsiveness to GTP, providing an alternative with potentially similar regulatory features. The data of both GLUD1 and GLUD2 evolution not only confirm substitutions enhancing GLUD2 mitochondrial targeting, but also reveal a conserved mutation in ape GLUD1 mitochondrial targeting sequence that likely reduces its transport to mitochondria. Moreover, the information of GDH interactors, posttranslational modification and subcellular localization are provided for better understanding of the GDH mutations. Medically significant point mutations causing deregulation of GDH are considered from the structural and regulatory point of view.

Characterization of the zebrafish as a model of ATP-sensitive potassium channel hyperinsulinism.

INTRODUCTION: Congenital hyperinsulinism (HI) is the leading cause of persistent hypoglycemia in infants. Current models to study the most common and severe form of HI resulting from inactivating mutations in the ATP-sensitive potassium channel (KATP) are limited to primary islets from patients and the Sur1 -/- mouse model. Zebrafish exhibit potential as a novel KATPHI model since they express canonical insulin secretion pathway genes and those with identified causative HI mutations. Moreover, zebrafish larvae transparency provides a unique opportunity for in vivo visualization of pancreatic islets. RESEARCH DESIGN AND METHODS: We evaluated zebrafish as a model for KATPHI using a genetically encoded Ca2+ sensor (ins:gCaMP6s) expressed under control of the insulin promoter in beta cells of an abcc8 -/- zebrafish line. RESULTS: We observed significantly higher islet cytosolic Ca2+ in vivo in abcc8 -/- compared with abcc8 +/+ zebrafish larvae. Additionally, abcc8 -/- larval zebrafish had significantly lower whole body glucose and higher whole body insulin levels compared with abcc8 +/+ controls. However, adult abcc8 -/- zebrafish do not show differences in plasma glucose, plasma insulin, or glucose tolerance when compared with abcc8 +/+ zebrafish. CONCLUSIONS: Our results identify that zebrafish larvae, but not adult fish, are a demonstrable novel model for advancement of HI research.

[Congenital hyperinsulinism : contributions of chemistry, therapeutic response, genetics and imaging]. / Hyperinsulinisme congénital : apports de la biologie, de la réponse thérapeutique, de la génétique et de l'imagerie.

Congenital hyperinsulinism is the most common cause of recurrent hypoglycemia in newborns and children. Early diagnosis and rapid management are essential to avoid hypoglycaemic brain injury and later neurological complications. Management of those patients involves biological evaluation, molecular genetics, imaging techniques and surgical advances. We report the case of a newborn with recurrent hypoglycemia due to congenital hyperinsulinism (CHI) caused by a new variant in the ABCC8 gene. Fluorine 18-L-3,4 Dihydroxyphenylalanine Positron Emission Tomography (18F-DOPA PET/CT scan) reported a focal lesion at the isthmus of the pancreas which has been removed by laparoscopic surgery with a complete recovery for the patient.

L'hyperinsulinisme congénital est la cause la plus fréquente d'hypoglycémies récidivantes chez le nouveau-né et l'enfant. Un diagnostic et une prise en charge précoces sont primordiaux pour éviter les conséquences potentielles sur le développement neurologique. Ces derniers reposent sur la conjonction d'éléments biologiques, génétiques et d'imagerie. Nous rapportons le cas d'un nouveau-né présentant des hypoglycémies récidivantes. La mise au point mettra en évidence un hyperinsulinisme congénital (CHI) lié à un variant non encore décrit au sein du gène ABCC8. L'imagerie par Fluorine 18-L-3,4 Dihydroxyphenylalanine Positron Emission Tomography/Computed Tomography-scanner (18F-DOPA PET/CT scan) a mis en évidence une forme focale de l'hyperinsulinisme justifiant une prise en charge chirurgicale amenant à une guérison complète et à l'arrêt de tout traitement médicamenteux.

Multifocal Insulinoma as the Unique Presenting Feature of Multiple Endocrine Neoplasia Type 1 in an Adolescent.

INTRODUCTION: Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant inherited disorder defined by the presence of two of the following endocrinopathies: primary hyperparathyroidism, anterior pituitary tumors, and duodenopancreatic neuroendocrine tumors (NETs). NETs, which can secrete hormones including insulin, gastrin, and glucagon, among others, are common in patients with MEN1 and are a major cause of morbidity and premature death. NETs are more common later in life, with very few cases described in children. Here, we describe a unique case of an adolescent with multifocal pancreatic NETs as the single presenting feature of MEN1. CASE PRESENTATION: A 13-year-old healthy male presented with severe weakness, altered mental status, and syncope in the setting of a venous blood glucose (BG) of 36 mg/dL. Workup showed an elevated insulin level (14 µIU/mL) when BG was 39 mg/dL with positive response to glucagon, concerning for hyperinsulinism. Diazoxide and chlorothiazide were started but not well tolerated secondary to emesis. Three suspected NETs were identified by magnetic resonance imaging and 68-Ga DOTATATE PET-CT imaging, including the largest, a 2.1 cm mass in the pancreatic head. A fourth mass in the pancreatic tail was identified via intraoperative ultrasound. All lesions were successfully enucleated and excised, and glucose levels normalized off diazoxide by post-op day 2. While the primary lesion stained for insulin and somatostatin by immunofluorescence (IF), consistent with his clinical presentation, the additional tumors expressed glucagon, somatostatin, pancreatic polypeptide, and chromogranin A but were negative for insulin. Genetic testing confirmed a pathogenic heterozygous mutation in MEN1 (c.969C>A, p.Tyr323). He had no other signs of MEN-associated comorbidities on screening. DISCUSSION/CONCLUSION: This case demonstrates that young patients with MEN1 can present with multifocal NETs. These NETs may have polyhormonal expression patterns despite a clinical presentation consistent with one primary hormone. Our patient had clinical symptoms and laboratory evaluation consistent with an insulinoma but was found to have four NETs, each with different IF staining patterns. Advanced preoperative and intraoperative imaging is important to identify and treat all present NETs. Moreover, serum hormone levels pre- and posttreatment could help evaluate whether NETs are actively secreting hormones into the bloodstream or simply expressing them within the pancreas. Finally, this case highlights the importance of genetic testing for MEN1 in all young patients with insulinomas.

Neonatal Graves disease with persistent hypoglycemia: A case report.

Neonatal Graves disease is the most common cause of hyperthyroidism during the newborn period. Maternal Graves disease increases the risk of intrauterine growth restriction, small for gestational age, and neonatal Graves disease. Intrauterine growth restriction and small for gestational age are associated with hypoglycemia and transient neonatal hyperinsulinism. Neonatal Graves disease with severe persistent hypoglycemia has not been well described. We present the case of a female patient born at 34 weeks and 3 days with a birth weight of 1.6 kg (fifth percentile) to a mother with recent treatment for Graves disease. Prenatal ultrasounds were significant for intrauterine growth restriction and small for gestational age. The mother did not begin hyperthyroidism medical therapy until 23 weeks and 2 days of gestation. After the infant was born, the infant not only had symptoms of hyperthyroidism such as tachycardia and abnormal thyroid values but also had persistent hypoglycemia, which could be due to maternal propranolol usage, prematurity, IUGR, increased metabolism due to neonatal Graves, and transient stress-induced hyperinsulinism. The infant was started on methimazole for hyperthyroidism and propranolol for tachycardia. She was also started on diazoxide for persistent hypoglycemia. By 6 months of age, the hyperthyroidism and hypoglycemia had resolved. This is an interesting case of neonatal Graves disease with severe persistent hypoglycemia which we suspect is due to transient neonatal hyperinsulinism induced by multiple stress responses.

A loss-of-function mutation in KCNJ11 causing sulfonylurea-sensitive diabetes in early adult life.

AIMS/HYPOTHESIS: The ATP-sensitive potassium (KATP) channel couples beta cell electrical activity to glucose-stimulated insulin secretion. Loss-of-function mutations in either the pore-forming (inwardly rectifying potassium channel 6.2 [Kir6.2], encoded by KCNJ11) or regulatory (sulfonylurea receptor 1, encoded by ABCC8) subunits result in congenital hyperinsulinism, whereas gain-of-function mutations cause neonatal diabetes. Here, we report a novel loss-of-function mutation (Ser118Leu) in the pore helix of Kir6.2 paradoxically associated with sulfonylurea-sensitive diabetes that presents in early adult life. METHODS: A 31-year-old woman was diagnosed with mild hyperglycaemia during an employee screen. After three pregnancies, during which she was diagnosed with gestational diabetes, the patient continued to show elevated blood glucose and was treated with glibenclamide (known as glyburide in the USA and Canada) and metformin. Genetic testing identified a heterozygous mutation (S118L) in the KCNJ11 gene. Neither parent was known to have diabetes. We investigated the functional properties and membrane trafficking of mutant and wild-type KATP channels in Xenopus oocytes and in HEK-293T cells, using patch-clamp, two-electrode voltage-clamp and surface expression assays. RESULTS: Functional analysis showed no changes in the ATP sensitivity or metabolic regulation of the mutant channel. However, the Kir6.2-S118L mutation impaired surface expression of the KATP channel by 40%, categorising this as a loss-of-function mutation. CONCLUSIONS/INTERPRETATION: Our data support the increasing evidence that individuals with mild loss-of-function KATP channel mutations may develop insulin deficiency in early adulthood and even frank diabetes in middle age. In this case, the patient may have had hyperinsulinism that escaped detection in early life. Our results support the importance of functional analysis of KATP channel mutations in cases of atypical diabetes.

Visual Perception in Children with a History of Hypoglycemia due to Hyperinsulinism.

Objectives: Hyperinsulinism refers to improper insulin secretion in the presence of low plasma glucose, causing severe and persistent hypoglycemia in infants and children. The brain's occipital lobe, which includes the visual and plays an essential role in visual perception is specifically sensitive to hypoglycemia-induced damage. The present study aims to investigate the visual perception in children suffering from hyperinsulinism and to compare it with the control group. Materials & Methods: This cross-sectional control study, conducted in 2020 in Isfahan, Iran, involved 20 children aged 4-13 years with hyperinsulinism and 20 healthy children of the same age and gender for comparison. In both groups, the measuring instrument was the Test of Visual Perceptual Skills (non-motor) Third Edition. Results: The mean visual perceptual quotient in the case and control groups was 80.50±26.74 and 116.50±7.56 (p-value<0.001), respectively. The results overall indicated that children suffering from hyperinsulinism were weaker than healthy children in all areas of visual perception. Conclusion: Based on the obtained results, it is recommended that children suffering from hyperinsulinism be screened regarding visual perceptual disorders since this screening may be helpful in initiating different rehabilitation programs among these patients.

Noninsulinoma Pancreatogenous Hypoglycemia Syndrome in a Patient With 1p36 Deletion Syndrome.

The 1p36 deletion syndrome involves a phenotypic presentation that includes central nervous system, cardiac, and craniofacial anomalies. We report the case of a 21-year-old female patient with 1p36 deletion syndrome who was found to have noninsulinoma pancreatogenous hypoglycemia syndrome (NIPHS) after hospitalization for persistent falls. On admission, vital signs were normal and physical examination revealed a thin, nonverbal patient. During hospitalization and prolonged fasting (14-18 hours), she persistently developed hypoglycemia (serum glucose nadir 57 mg/dL [3.2 mmol/L] [70-100 mg/dL; 3.9-5.6 mmol/L]). Subjective symptoms of hypoglycemia were not confirmed due to patient's cognitive impairment. Hypoglycemic events continued despite feeding and dextrose-containing fluids. Further workup included a critical sample that revealed a serum glucose 59 mg/dL (3.3 mmol/L), insulin 20.6 µIU/mL (123.6 pmol/L [5-15 µIU/mL; 30.0-90 pmol/L]), proinsulin 33 pmol/L (3.6-22 pmol/L), C-peptide 1.74 ng/mL (0.58 nmol/L [0.8-3.85 ng/mL; 0.27-1.28 nmol/L]) and beta-hydroxybutyrate < 1.04 mg/dL (< 0.10 mmol/L; [< 4.2 mg/dL; < 0.4 mmol/L]). Insulin antibodies were negative. After confirmed insulin-mediated hypoglycemia, imaging studies followed. Pancreatic protocol abdominal computed tomography (CT), Ga-68 DOTATATE PET/CT scan, and endoscopic ultrasound found no pancreatic mass. Selective arterial calcium stimulation test showed a two-fold increase in insulin levels in 3/3 catheterized pancreatic territories. The patient started octreotide injections with resolution of hypoglycemia and was discharged on monthly lanreotide injections. To our knowledge, this is the first case reported of noninsulinoma pancreatogenous hypoglycemia in a patient with 1p36 deletion syndrome.