Congenital hyperinsulinism: localization of a focal lesion with 18F-FDOPA positron emission tomography.

Hyperinsulinemic hypoglycemia of infancy, also known as congenital hyperinsulinism, is a group of disorders characterized by dysregulated insulin release. Neonates with severe, persistent hyperinsulinemic hypoglycemia who are unresponsive to medical therapy require pancreatectomy to prevent brain damage from hypoglycemia. To date, multiple genetic mutations and syndromes and several unique histopathological entities have been identified in children with hyperinsulinism. Histopathology is characterized as diffuse, focal or atypical. Surgical resection of a focal lesion results in a cure in up to 97% of these children. Imaging with 6-fluoro-(18F)-L-3,4-dihydroxyphenylalanine (18F-FDOPA) positron emission tomography (PET) is the test of choice for identifying and localizing a focal lesion and has proved to be an invaluable guide for surgical resection. Genetic evaluation is essential for determining who will benefit from PET imaging. This article provides an approach to determine who should be imaged, how to set up a protocol and how to interpret the imaging findings. The diagnosis and management of this disorder require a multidisciplinary approach to prevent brain damage from hypoglycemia.

Differential effects of androgens, estrogens and socio-sexual context on sexual behaviors in the castrated male goat.

The behavioral and endocrine activation of sexual behaviors exhibited by male goats, especially self-enurination (SE), is poorly understood. In the first experiment, to assess the influence of socio-sexual context on SE in bucks, the effects of distance from does, the presence of estrous versus non-estrous does and the presence of another buck on SE and courtship frequencies of intact male goats (bucks; n = 12) were tested using a unique behavior test apparatus. For experiments 2 and 3, to test the relative contributions of sex steroid hormones and socio-sexual context on SE, castrated male goats (wethers; n = 20) were randomly divided into five groups and injected for seven weeks with one of the following: 25 mg testosterone propionate (T), 25 mg dihydrotestosterone propionate (DHT), 100 µg estradiol benzoate (E), 100 µg E and 25 mg DHT (E + DHT), or oil (CON). The effects of these treatments on frequency of SE and courtship were assessed using the behavior test apparatus (social scenarios) adapted from the findings in experiment 1. In one scenario, a wether could observe (from 4.6 m) a buck and estrous female (doe) together in a wire mesh holding pen. In a different scenario, the wether could observe (from the same distance) a buck that could only court the estrous doe through a wire mesh barrier. Finally, to observe the effects of steroid treatment on mounting and ejaculation frequencies, in addition to SE and courtship, each wether was placed in a pen with an estrous doe for 10 min. After a five-week, treatment-washout period, wethers were randomly assigned to different treatment groups and retested. In experiment 1, bucks that were distanced from females displayed more SEs than those with fence-line contact, while those with fence-line contact displayed more bouts of courtship (P < 0.05). In experiments 2 and 3, courtship frequencies displayed in all three scenarios were greater than CON only for groups exposed to estrogen directly or via aromatization (T, E + DHT, E; P < 0.05). Frequencies of SE exhibited during behavior tests in which the wether was watching were greater than CON only for androgen-treated groups (T, E + DHT, DHT; P < 0.05). In contrast, when the wether was free to interact with the female, only the DHT group displayed SE at a higher frequency than CON (P < 0.05). Treatment had no effect on mount frequencies in this test scenario, however ejaculation frequencies were highest for T and E + DHT (P < 0.05). These studies suggest that the courtship behaviors of the male goat are estrogen-dependent. However, SE appears to be activated by androgens. It was also demonstrated that social context contributes as much to behavior expression as steroid treatment, as in social scenario 2 some sexual behaviors were displayed in similar frequencies across groups, despite differing sex steroid treatments.

Congenital hyperinsulinism in children with paternal 11p uniparental isodisomy and Beckwith-Wiedemann syndrome.

BACKGROUND: Congenital hyperinsulinism (HI) can have monogenic or syndromic causes. Although HI has long been recognised to be common in children with Beckwith-Wiedemann syndrome (BWS), the underlying mechanism is not known. METHODS: We characterised the clinical features of children with both HI and BWS/11p overgrowth spectrum, evaluated the contribution of KATP channel mutations to the molecular pathogenesis of their HI and assessed molecular pathogenesis associated with features of BWS. RESULTS: We identified 28 children with HI and BWS/11p overgrowth from 1997 to 2014. Mosaic paternal uniparental isodisomy for chromosome 11p (pUPD11p) was noted in 26/28 cases. Most were refractory to diazoxide treatment and half required subtotal pancreatectomies. Patients displayed a wide range of clinical features from classical BWS to only mild hemihypertrophy (11p overgrowth spectrum). Four of the cases had a paternally transmitted KATP mutation and had a much more severe HI course than patients with pUPD11p alone. CONCLUSIONS: We found that patients with pUPD11p-associated HI have a persistent and severe HI phenotype compared with transient hypoglycaemia of BWS/11p overgrowth patients caused by other aetiologies. Testing for pUPD11p should be considered in all patients with persistent congenital HI, especially for those without an identified HI gene mutation.

Biomarkers of Insulin for the Diagnosis of Hyperinsulinemic Hypoglycemia in Infants and Children.

OBJECTIVE: To evaluate thresholds of various biomarkers for defining excess insulin activity to recognize congenital hyperinsulinism. STUDY DESIGN: This was a retrospective chart review of diagnostic fasting tests in children with ketotic hypoglycemia (n = 30) and genetically/pathology confirmed congenital hyperinsulinism (n = 28). Sensitivity and specificity for congenital hyperinsulinism were determined for plasma insulin, ß-hydroxybutyrate, free fatty acids (FFA), C-peptide, insulin-like growth factor binding protein-1 (IGFBP-1), and the glycemic response to glucagon (through the glucagon stimulation test [GST]) at the time of hypoglycemia. RESULTS: Only 23 of the 28 subjects with congenital hyperinsulinism had detectable insulin (median, 6.7 µIU/mL), and insulin was undetectable in all subjects with ketotic hypoglycemia. Compared with ketotic hypoglycemia, subjects with congenital hyperinsulinism had higher GST values (57 vs 13 mg/dL; ΔGST ≥30 mg/dL in 24 of 27 subjects with congenital hyperinsulinism vs 0 of 30 subjects with ketotic hypoglycemia) and C-peptide levels (1.55 vs 0.11 ng/mL), with lower levels of FFA (0.82 vs 2.51 mM) and IGFBP-1 (59.5 vs 634 ng/mL). At the time of hypoglycemia, the upper limits of ß-hydroxybutyrate and FFA in subjects with congenital hyperinsulinism were higher than reported previously (ß-hydroxybutyrate <1.8 mM and FFA <1.7 mM), providing the best sensitivity for congenital hyperinsulinism vs ketotic hypoglycemia. A C-peptide level ≥0.5 ng/mL was 89% sensitive and 100% specific, and an IGFBP-1 level ≤110 ng/mL was 85% sensitive and 96.6% specific. CONCLUSION: Because low or undetectable insulin level during hypoglycemia does not exclude the diagnosis of hyperinsulinism, C-peptide and IGFBP-1 may inform the diagnosis of congenital hyperinsulinism. In this group of children with well-defined congenital hyperinsulinism, thresholds for "suppressed" ß-hydroxybutyrate and FFA are higher than previously reported levels.

Novel Use of Dasiglucagon, a Soluble Glucagon Analog, for the Treatment of Hyperinsulinemic Hypoglycemia Secondary to Suspected Insulinoma: A Case Report.

INTRODUCTION: Hyperinsulinemic hypoglycemia is the most common cause of persistent hypoglycemia in children and adults. In adolescents and adults, hyperinsulinemic hypoglycemia is most frequently caused by an insulin-producing tumor. CASE PRESENTATION: A 17-year-old, previously healthy male presented with recurrent and severe episodes of hypoglycemia. Diagnostic evaluation was consistent with hyperinsulinemic hypoglycemia, and an insulinoma was suspected. Multiple imaging studies and surgical exploration failed to identify a lesion. Over the course of months, the patient was found to be refractory to conventional medical interventions. CONCLUSION: Upon approval from the US Food and Drug Administration and the Institutional Review Board, the patient was treated with dasiglucagon, a novel soluble glucagon analog, under a single-patient Investigational New Drug. The patient has tolerated the medication and has been able to achieve appropriate glycemic control.

Developing content for American Board of Pediatric Dentistry certification examinations using practice analysis.

BACKGROUND: The American Board of Pediatric Dentistry (ABPD) conducted a practice analysis to guide the development of its certification examination outlines for assessing the knowledge, skills, and abilities of pediatric dentists. This article describes the systematic approach used by the ABPD. METHODS: The ABPD conducted its practice analysis in 4 phases: (1) preparation, (2) focus group meetings, (3) survey, and (4) examination blueprint development. RESULTS: Phase 2 resulted in 150 job tasks relevant to entry-level pediatric dental practice, organized into 10 domains. In Phase 3, 8,730 pediatric dentists received an electronic survey, with 10% returning a completed survey. Respondents rated tasks in terms of frequency and risk, which were analyzed to determine the combined relevance of each task. Phase 4 organized a final list of tasks within each domain and the recommended weighting of domains by certifying examination. CONCLUSIONS: The ABPD practice analysis created a comprehensive outline of the job tasks an entry-level pediatric dentist is expected to perform. The ABPD plans to use the results to help develop the examination content for continuing certification and will use a similar process every 5 through 7 years to update the examination content blueprints to ensure their continued relevance to the practice of pediatric dentistry. PRACTICAL IMPLICATIONS: The ABPD used a process known as practice analysis to ensure that its examinations and continued competency assessments measure the knowledge, skills, and abilities required for safe and effective clinical practice.

Establishing performance standards for child development: learnings from the ECDI2030.

BACKGROUND: Standards of early childhood development (ECD) are needed to determine whether children living in different contexts are developmentally on track. The Early Childhood Development Index 2030 (ECDI2030) is a population-level measure intended to be used in household surveys to collect globally comparable data on one of the indicators chosen to monitor progress toward target 4.2 of the Sustainable Development Goals: The proportion of children aged 24-59 months who are developmentally on track in health, learning and psychosocial well-being. METHODS: To define performance cut-scores for the ECDI2030 we followed a criterion-referenced standard setting exercise using the modified Angoff method. The exercise gauged the expectations from 15 global experts in ECD and was informed by representative population data collected in Mexico and the State of Palestine. The final calibrated age-specific performance cut-scores were applied to these data to estimate the proportion of children developmentally on track, disaggregated by background characteristics, including the child's sex and attendance to early childhood education. RESULTS: Through a process of standard setting, we generated robust performance standards for the ECDI2030 by establishing five age-specific cut-scores to identify children as developmentally on track. CONCLUSIONS: This paper demonstrated how the standard setting methodology, typically applied to measures in the health and education fields, could be applied to a measure of child development. By creating robust criterion-referenced standards, we have been able to ensure that the cut-scores related to age for the ECDI2030 are based on performance standards set by global experts in the ECD field for defining on and off track development.

Effect of proximity to females on integument damage caused by self-enurination in male goats.

In male goats, self-enurination (SE) is the downward turning of the head and shoulders while urinating onto the face and front legs. Although it provides important chemical cues to females, other males, and even self, it is a costly behavior that can create a range of problems including erythema, irritation, hair loss, and compromised skin. It was hypothesized that the extent of integument damage from SE on bucks' faces and front legs would be increased by housing bucks near females. Four bucks were housed with fence-line contact to females ("Near" bucks), and four bucks were housed without fence-line contact to females ("Far" bucks). Each buck was photographed every other week over an 18-wk period during the breeding season. During each imaging session, seven different photographic views were captured, and burn areas were quantified for each buck. Overall, more Near bucks had urine burn than Far bucks, and Near bucks developed urine burn earlier in the breeding season than did Far bucks. Housing bucks close to females increases the extent of integument damage from SE. These findings may help goat breeders develop management practices to improve animal well-being by minimizing urine burn injury to bucks.

Localized islet nuclear enlargement hyperinsulinism (LINE-HI) due to ABCC8 and GCK mosaic mutations.

Objective: Congenital hyperinsulinism (HI) is the most common cause of persistent hypoglycemia in children. In addition to typical focal or diffuse HI, some cases with diazoxide-unresponsive congenital HI have atypical pancreatic histology termed Localized Islet Nuclear Enlargement (LINE) or mosaic HI, characterized by histologic features similar to diffuse HI, but confined to only a region of pancreas. Our objective was to characterize the phenotype and genotype of children with LINE-HI. Design: The phenotype and genotype features of 12 children with pancreatic histology consistent with LINE-HI were examined. Methods: We compiled clinical features of 12 children with LINE-HI and performed next-generation sequencing on specimens of pancreas from eight of these children to look for mosaic mutations in genes known to be associated with diazoxide-unresponsive HI (ABCC8, KCNJ11, and GCK). Results: Children with LINE-HI had lower birth weights and later ages of presentation compared to children with typical focal or diffuse HI. Partial pancreatectomy in LINE-HI cases resulted in euglycemia in 75% of cases; no cases have developed diabetes. Low-level mosaic mutations were identified in the pancreas of six cases with LINE-HI (three in ABCC8, three in GCK). Expression studies confirmed that all novel mutations were pathogenic. Conclusion: These results indicate that post-zygotic low-level mosaic mutations of known HI genes are responsible for some cases of LINE-HI that lack an identifiable germ-line mutation and that partial pancreatectomy may be curative for these cases.

Clinical characteristics and biochemical mechanisms of congenital hyperinsulinism associated with dominant KATP channel mutations.

Congenital hyperinsulinism is a condition of dysregulated insulin secretion often caused by inactivating mutations of the ATP-sensitive K+ (KATP) channel in the pancreatic beta cell. Though most disease-causing mutations of the 2 genes encoding KATP subunits, ABCC8 (SUR1) and KCNJ11 (Kir6.2), are recessively inherited, some cases of dominantly inherited inactivating mutations have been reported. To better understand the differences between dominantly and recessively inherited inactivating KATP mutations, we have identified and characterized 16 families with 14 different dominantly inherited KATP mutations, including a total of 33 affected individuals. The 16 probands presented with hypoglycemia at ages from birth to 3.3 years, and 15 of 16 were well controlled on diazoxide, a KATP channel agonist. Of 29 adults with mutations, 14 were asymptomatic. In contrast to a previous report of increased diabetes risk in dominant KATP hyperinsulinism, only 4 of 29 adults had diabetes. Unlike recessive mutations, dominantly inherited KATP mutant subunits trafficked normally to the plasma membrane when expressed in COSm6 cells. Dominant mutations also resulted in different channel-gating defects, as dominant ABCC8 mutations diminished channel responses to magnesium adenosine diphosphate or diazoxide, while dominant KCNJ11 mutations impaired channel opening, even in the absence of nucleotides. These data highlight distinctive features of dominant KATP hyperinsulinism relative to the more common and more severe recessive form, including retention of normal subunit trafficking, impaired channel activity, and a milder hypoglycemia phenotype that may escape detection in infancy and is often responsive to diazoxide medical therapy, without the need for surgical pancreatectomy.

18F-6-Fluoro-l-Dopa PET/CT Imaging of Congenital Hyperinsulinism.

Congenital hyperinsulinism is characterized by persistent hypoglycemia due to inappropriate excess secretion of insulin resulting in hyperinsulinemic hypoglycemia. The clinical course varies from mild to severe, with a significant risk for brain damage. Imaging plays a valuable role in the care of infants and children with severe hypoglycemia unresponsive to medical therapy. 18F-6-fluoro-l-dopa PET/CT is the method of choice for the detection and localization of a focal lesion of hyperinsulinism. Surgical resection of a focal lesion can lead to a cure with limited pancreatectomy. This article reviews the role of 18F-6-fluoro-l-dopa PET/CT in the management of this vulnerable population.

Case Report: Two Distinct Focal Congenital Hyperinsulinism Lesions Resulting From Separate Genetic Events.

Focal hyperinsulinism (HI) comprises nearly 50% of all surgically treated HI cases and is cured if the focal lesion can be completely resected. Pre-operative localization of the lesion is thus critical. Few cases of hyperinsulinism with multiple focal lesions have been reported, and assessment of the molecular mechanisms driving this rare occurrence has been limited. We present two cases of multifocal HI, each resulting from two independent, pancreatic focal lesions. 18Fluoro-dihydroxyphenylalanine positron emission tomography/computed tomography detected both lesions preoperatively in one patient, whereas identification of the second lesion was an incidental finding during surgical exploration in the other. Complete resection of the focal lesions resulted in cure of the HI in both cases. In each patient, genetic testing of the individual focal lesions revealed different regions of loss of heterozygosity for the maternal 11p15 allele, confirming that each lesion arose from independent somatic events in the setting of a paternally inherited germline ABCC8 mutation. These cases highlight the importance of a multidisciplinary and personalized approach to the management of infants with HI.

Comparing Care of the Primary and Secondary Hemochromatosis Patients.

Hemochromatosis is an imbalance of excessive serum iron and is a life-threatening condition if left untreated. Due to different causes, primary and secondary hemochromatosis have different patient care considerations for the infusion nurse. Understanding the pathophysiology and how the body absorbs iron is imperative for providing the highest quality care. Since primary (hereditary) hemochromatosis originates from a gene mutation, and secondary (acquired) from excessive intake, the treatment and education must be adjusted accordingly to deliver successful outcomes for both diagnoses.

The Society of Thoracic Surgeons Composite Score Rating for Pulmonary Resection for Lung Cancer.

BACKGROUND: The Society of Thoracic Surgeons (STS) General Thoracic Surgery Database (GTSD) has developed composite quality measures for lobectomy and esophagectomy. This study sought to develop a composite measure including all resections for lung cancer. METHODS: The STS lung cancer composite score is based on 2 outcomes: risk-adjusted mortality and morbidity. GTSD data were included from January 2015 to December 2017. "Star ratings" were created for centers with 30 or more cases by using 95% Bayesian credible intervals. The Bayesian model was performed with and without inclusion of the minimally invasive approach to assess the impact of approach on the composite measure. RESULTS: The study population included 38,461 patients from 256 centers. Overall operative mortality was 1.3% (495 of 38,461). The major complication rate was 7.9% (3045 of 38,461). The median number of nodes examined was 10 (interquartile range, 5 to 16); the median number of nodal stations sampled was 4 (interquartile range, 3 to 5). Positive resection margins were identified in 3.7% (1420 of 38,461). A total of 214 centers with 30 or more cases were assigned star ratings. There were 7 1-star, 194 2-star, and 13 3-star programs; 70.6% of resections were performed through a minimally invasive approach. Inclusion of minimally invasive approach, which was adjusted for in previous models, altered the star ratings for 3% (6 of 214) of the programs. CONCLUSIONS: Participants in the STS GTSD perform lung cancer resection with low morbidity and mortality. Lymph node data suggest that participants are meeting contemporary staging standards. There is wide variability among participants in application of minimally invasive approaches. The study found that risk adjustment for approach altered ratings in 3% of participants.

Psychosocial care for women survivors of the tsunami disaster in India.

OBJECTIVES: I investigated the effectiveness of Psychosocial Care, a community-based mental health initiative for survivors of the 2004 tsunami disaster in India. METHODS: Mental health teams from the National Institute of Mental Health and Neurosciences (NIMHANS) in India implemented a train-the-trainer model of psychosocial care in one of the worst tsunami-affected areas of south India. Three months of psychosocial care was provided for an intervention group of women, but not for a control group recruited from an exposed neighboring village. Impact of Event Scale (IES) scores--both total scores and scores for subscales on hypervigilance, avoidance, and intrusion--were compiled for both the intervention and control groups and used as outcome measures. RESULTS: For the intervention group, posttest total IES and subscale scores were significantly lower than pretest scores (P < .001), indicating improvement in symptoms. Posttest total IES and subscale scores were significantly lower for the intervention group than for the control group (P < .001). CONCLUSIONS: Psychosocial care is an effective mental health strategy for women survivors of disasters and should be an integral component of disaster response in resource-poor countries.

Surgical treatment of congenital hyperinsulinism: Results from 500 pancreatectomies in neonates and children.

BACKGROUND: Congenital Hyperinsulinism (HI) causes severe hypoglycemia in neonates and children. We reviewed our experience with pancreatectomy for the various types of HI. METHODS: From 1998 to 2018, 500 patients with HI underwent pancreatectomy: 246 for focal HI, 202 for diffuse HI, 37 for atypical HI (16 for Localized Islet Nuclear Enlargement [LINE], 21 for Beckwith-Wiedemann Syndrome), and 15 for insulinoma. Focal HI neonates were treated with partial pancreatectomy. Patients with diffuse HI who failed medical management underwent near-total (98%) pancreatectomy. Atypical HI patients had pancreatectomies tailored to the PET scan and biopsy findings. RESULTS: The vast majority of pancreatectomies for focal HI were < 50%, and many were 2%-10%. 97% of focal HI patients are cured. For diffuse disease patients, 31% were euglycemic, 20% were hyperglycemic, and 49% required treatment for hypoglycemia; the incidence of diabetes increased with long-term follow-up. All 15 insulinoma patients were cured. CONCLUSIONS: Our approach to patients with focal HI can distinguish focal from diffuse HI, localize focal lesions, and permit partial pancreatectomy with cure in almost all focal patients. Surgery does not cure diffuse disease but can help prevent severe hypoglycemia and brain damage. Surgery can be curative for insulinoma and for some cases of atypical HI. LEVEL OF EVIDENCE: Level IV.

The Society of Thoracic Surgeons General Thoracic Surgery Database 2019 Update on Outcomes and Quality.

The Society of Thoracic Surgeons General Thoracic Surgery Database (STS GTSD) remains the most robust thoracic surgical database in the world, providing participating institutions semiannual risk-adjusted performance reports and facilitating multiple quality improvement initiatives each year. In 2018, the STS GTSD Data Collection Form was substantially revised to acquire the most important variables with the least data manager burden. In addition, a composite quality measure for all pulmonary resections for cancer was developed, and the impact that minimally invasive approaches have on the model was assessed. The 2018 database audit found that the accuracy of the database remains high, ranging from 92.5% to 98.4%. In 2019, the STS GTSD Task Force plans to focus on increasing generalizability of the database, initiating esophagectomy outcome public reporting, and creating customizable real-time dashboards. This review summarizes all national aggregate outcome, quality measurement, and improvement initiatives from the STS GTSD over the past 12 months.

From Death to Health in 30 Days: A Hemochromatosis Case Report.

BACKGROUND: Heredity hemochromatosis (HH) is an underdiagnosed genetic disease that can lead to life-threatening multisystem organ failure. Identifying and treating HH early can prevent the progression of the disease. CASE PRESENTATION: For a 60-year-old white patient without obvious symptoms, it was a revelation to discover that he had HH. This patient, although receiving evidence-based care, ultimately required a liver transplant. As his condition deteriorated, the plan for this patient and his family involved working within an interdisciplinary team that included nurse practitioners and intensive care unit nurses. DISCUSSION: The uniqueness of this case illustrates the crucial role of a health care team that persisted in differentiating the patient's diagnosis and continued to sustain both physical and emotional care throughout his hospitalization despite a poor prognosis. The patient felt support from this team during the course of his illness, from requiring life-supporting care in intensive care unit to returning home and resuming his normal activities of daily living.

The Society of Thoracic Surgeons General Thoracic Surgery Database 2018 Update on Outcomes and Quality.

For nearly 15 years The Society of Thoracic Surgeons General Thoracic Surgery Database (STS GTSD) has provided participating institutions with risk-adjusted feedback reports that allow outcome comparisons relative to national benchmarks. With more than 300 contributing centers across North America, the STS GTSD now includes more than 530,000 cases. In 2017 the STS GTSD Task Force revised the data collection form with the goal of collecting more detailed and accurate information for the most important thoracic surgical cases without increasing the workload of registrars. In addition, the learning curve for thoracoscopic lobectomy was examined, online public reporting was initiated, institutional feedback reports were made more user-friendly, and collaboration with the European Society of Thoracic Surgery continued. The STS GTSD Task Force continues to work to improve the quality of care and support research initiatives in general thoracic surgery. This report summarizes current aggregate national outcomes in general thoracic surgery and reviews related activities in the areas of quality measurement, performance improvement, and transparency from the STS GTSD during the past 12 months.

Congenital Hyperinsulinism in Infants with Turner Syndrome: Possible Association with Monosomy X and KDM6A Haploinsufficiency.

BACKGROUND: Previous case reports have suggested a possible association of congenital hyperinsulinism with Turner syndrome. OBJECTIVE: We examined the clinical and molecular features in girls with both congenital hyperinsulinism and Turner syndrome seen at The Children's Hospital of Philadelphia (CHOP) between 1974 and 2017. METHODS: Records of girls with hyperinsulinism and Turner syndrome were reviewed. Insulin secretion was studied in pancreatic islets and in mouse islets treated with an inhibitor of KDM6A, an X chromosome gene associated with hyperinsulinism in Kabuki syndrome. RESULTS: Hyperinsulinism was diagnosed in 12 girls with Turner syndrome. Six were diazoxide-unresponsive; 3 had pancreatectomies. The incidence of Turner syndrome among CHOP patients with hyperinsulinism (10 of 1,050 from 1997 to 2017) was 48 times more frequent than expected. The only consistent chromosomal anomaly in these girls was the presence of a 45,X cell line. Studies of isolated islets from 1 case showed abnormal elevated cytosolic calcium and heightened sensitivity to amino acid-stimulated insulin release; similar alterations were demonstrated in mouse islets treated with a KDM6A inhibitor. CONCLUSION: These results demonstrate a higher than expected frequency of Turner syndrome among children with hyperinsulinism. Our data suggest that haploinsufficiency for KDM6A due to mosaic X chromosome monosomy may be responsible for hyperinsulinism in Turner syndrome.