Congenital hyperinsulinism

Congenital hyperinsulinism is a cause of persistent hypoglycaemia in the neonatal period. It is a heterogeneous disease with respect to clinical presentation, molecular biology, genetic aetiology and response to medical therapy. The clinical heterogeneity may range from severe life-threatening disease to very mild clinical symptoms. Recent advances have begun to clarify the molecular pathophysiology of this disease, but despite these advances treatment options remain difficult and there are many long-term complications. So far mutations in five different genes have been identified in patients with congenital hyperinsulinism. Most cases are caused by mutations in genes coding for either of the two subunits of the beta-cell K(ATP) channel (ABCC8 and KCNJ11). Two histological subtypes of the disease - diffuse and focal - have been described. The preoperative histological differentiation of these two subtypes is now mandatory as surgical management will be radically different. The ability to distinguish diffuse from focal lesions has profound implications for therapeutic approaches, prognosis and genetic counselling.     

Congenital hyperinsulinism: Global and Japanese perspectives

Over the past 20 years, there has been remarkable progress in the diagnosis and treatment of congenital hyperinsulinism (CHI). These advances have been supported by the understanding of the molecular mechanism and the development of diagnostic modalities to identify the focal form of ATP‐sensitive potassium channel CHI. Many patients with diazoxide‐unresponsive focal CHI have been cured by partial pancreatectomy without developing postsurgical diabetes mellitus. Important novel findings on the genetic basis of the other forms of CHI have also been obtained, and several novel medical treatments have been explored. However, the management of patients with CHI is still far from ideal. First, state‐of‐the‐art treatment is not widely available worldwide. Second, it appears that the management strategy needs to be adjusted according to the patient's ethnic group. Third, optimal management of patients with the diazoxide‐unresponsive, diffuse form of CHI is still insufficient and requires further improvement. In this review, we describe the current landscape of this disorder, discuss the racial disparity of CHI using Japanese patients as an example, and briefly note unanswered questions and unmet needs that should be addressed in the near future.     

先天性高胰岛素血症

报道1例先天性持续性高胰岛素性低血糖症患儿的临床诊治情况。患儿,男,孕36周,因“胎儿宫内窘迫”剖宫产出生,出生体重4200g,生后即表现为反复低血糖,加用糖皮质激素治疗后患儿的血糖仍一直波动于1.2~2.8mmol/L之间,需静脉输注10%葡萄糖溶液,糖速为10~17mg/(kg·min),才能维持血糖的稳定。生后30d测定血胰岛素浓度为24.13U/L,同份标本的血糖为1.5mmol/L,血浆胰岛素(U/L)/血浆葡萄糖(mg/dL)比值为0.89,表明体内存在器质性胰岛素不适当分泌过多,诊断为先天性高胰岛素血症。     

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??Abstract?? Objective??To study the diagnosis and treatment of neonatal Congenital Hyperinsulinism Hypoglycemia??CHI??. Methods??The clinical data of 15 newborn babies with CHI??who were diagnosed in Beijing Children’s Hospital between 2000 and 2010??were retrospectively reviewed. Results??Sex ratio of boys to girls was 10??4. Time variation in disease onset?? from less than 1 hour after labor to 25 days. ten of 15 patients were large for gestational age?? 8 of them were macrosonias. Convulsion??cyanosis??lethargy??refusing milk sucking??irritability and sweating were common symptoms. The laboratory findings displayed persistent hypoglycemia and hyperinsulinism in all of the 15 newborn babies. There were no urine and blood ketones elevating in all of the 15 newborn babies. Nine infants were treated with oral diazoxide??but only 2 of them showed effectiveness to the therapy. One patient was given subtotal pancreatectomy and the blood glucose level was restored to normal after operation. Two newborn babies died within 2 weeks. Of the other 13 newborn babies??only 3 who were effectively treated had normal intelligence. Nine of them presented mental retardation in a 5-year follow-up. Conclusion??The measurement of blood glucose??blood insulin and urinary ketones is helpful in the diagnosis of persistent hyperinsulinemic hypoglycemia of infancy. Most patients have no response to diazoxide therapy. Whenever drug treatment is comfirmed unresponsive??operation should be considered.     

先天性巨结肠结肠组织钾离子通道的表达变化

目的 通过离子通道芯片及Western blot实验证实先天性巨结肠(Hirschsprungdisease,HD)病变肠段的钾离子通道表达与正常的结直肠存在差异.方法 2012年8月到2013年12月在哈尔滨医科大学附属第一医院手术治疗先天性巨结肠患儿30例,通过病史、直肠测压、钡剂灌肠造影、术中冰冻及术后病理等确诊为HD,术中结肠切除完成后,分别取正常及病变狭窄段肠组织,大小为1.0 cm×1.0 cm;标本置入液氮中冻存以待进一步实验.取其中6组标本,应用人类神经离子通道PCR芯片(neuronal ion channels PCR array)进行筛选表达具有差异性的钾离子通道;全部30例标本应用Western blot检测所筛选出钾离子通道的表达情况.结果采用Image-Pro Plus魔棒选取蛋白条带,利用IOD算法计算条带灰度.结果 我们将表达变化在2倍以上的基因认定为是差异表达基因,从而通过芯片筛选出表达具有差异性的钾离子通道1 5个,其中无神经节肠段表达增强1个,表达降低14个,共包括电压门控性的钾离子通道9个、大电导Ca2+激活的K+通道2个、小电导Ca2+激活的K+通道2个、内向整流性钾离子通道2个.利用Westernblot验证大电导Ca2+激活的K+通道的Maxi K通道及电压门控性钾离子通道的Kv11.1通道a亚基蛋白的表达.并经统计学分析,认定差异具有显著差异性.结论 先天性巨结肠结肠组织中确实存在表达下调的钾离子通道.     

Histopathology of Congenital Hyperinsulinism: Retrospective Study with Genotype Correlations

The majority of the most severe cases of congenital hyperinsulinism (HI) are caused by defects in the -cell adenosine triphosphate (ATP)-sensitive potassium channel and usually require pancreatectomy to control blood sugar levels. In contrast to the recent advances in understanding the pathophysiology and genetic bases of HI, the histologic classification of this condition remains controversial. A recent proposal to classify the HI pancreata into diffuse and focal forms has drawn much interest because of its relative simplicity and its good correlation with the genetic abnormalities. We undertook a retrospective study to determine whether this classification scheme could be applied to 38 pancreata resected for HI at our institution. We also obtained leukocyte genomic DNA from 29 cases and screened the exons of ABCC8 and KCNJ11 genes for the presence of mutations. Nineteen cases (50.0%) were histologically classified as diffuse HI and 14 cases (36.8%) were categorized as focal form. The mutational analysis revealed that 14 of the 16 diffuse cases analyzed had either homozygous or compound heterozygous mutations of ABCC8 or KCNJ11 and 7 of 10 focal cases had only the paternally inherited mutations, consistent with the previous observations. Two patients (5.3%) had normal pancreatic histology but had persistent hypoglycemia postoperatively, leaving the possibility of residual focal lesion. Three of 38 cases (7.9%) did not fit well into either diffuse or focal category. Two cases differed from the described pattern for the diffuse form in that the nuclear enlargement was confined to a single area of the pancreas. The other case had a focal lesion but -cell nuclear enlargement was present in nonadjacent areas. Mutations for typical diffuse or focal HI were not identified in two of these three equivocal cases. We conclude from this study that nearly 90% of HI cases can be classified into either a diffuse or a focal form. However, a small percentage of cases represented a diagnostic challenge.     

A severe case of hyperinsulinism due to hemizygous activating mutation of glutamate dehydrogenase

Activating mutations in the GLUD1 gene, which encodes glutamate dehydrogenase (GDH), result in the hyperinsulinism‐hyperammonemia syndrome. GDH is an allosterically regulated enzyme responsible for amino acid‐mediated insulin secretion via the oxidative deamination of glutamate to 2‐oxoglutarate, leading to ATP production and insulin release. This study characterizes a novel combination of mutations in GLUD1 found in a neonate who presented on the first day of life with severe hypoglycemia, hyperammonemia, and seizures. Mutation analysis revealed a novel frameshift mutation (c.37delC) inherited from the asymptomatic mother that results in a truncated protein and a de novo activating mutation (p.S445L) close to the GTP binding site that has previously been reported. GTP inhibition of GDH enzyme activity in 293T cells expressing the p.S445L or wild‐type GDH showed that the half‐maximal inhibitory concentration (IC₅₀) for GTP was approximately 800 times higher for p.S445L compared to wild type. GTP inhibition of GDH activity in lymphoblasts from the patient, from a heterozygote for the p.S445L mutation, and in wild‐type lymphoblasts showed that the IC₅₀ for GTP of the patient was approximately 200 times that of wild type and 7 times that of heterozygote. However, while the patient had a loss of GTP inhibition of GDH that was more severe than that of heterozygotes, the patient's clinical phenotype is similar to typical heterozygous mutations of GDH. This is the first time we have observed a functionally homozygous activating mutation of GDH in a human.     

A case of familial nesidioblastosis: prenatal diagnosis of foetal hyperinsulinism

Persistent neonatal hyperinsulinaemic hypoglycaemia due to nesidioblastosis is a rare condition probably transmitted by an autosomal recessive inheritance. Recurrent hypoglycaemic episodes become evident after birth and cause severe neurological damage without intensive treatment. The intrauterine detection of hypoglycaemia and hyperinsulinism in newborns subsequently diagnosed as affected by nesidioblastosis has not yet been reported. We describe a case of familial nesidioblastosis in which an intrauterine diagnosis could be suggested by high levels of insulin and C-peptide and low values of glucose in the amniotic fluid.     

Somatostatin analogue SMS 201-995 in the short-term management of neonatal hyperinsulinism due to nesidioblastosis

Abstract A neonate with persistent hyperinsulinaemic hypoglycaemia is presented in whom the use of intravenous somatostatin SMS 201-995 allowed good glycaemic control over 10 days. A 95% pancreatectomy was then performed.     

Severe transient hyperinsulinaemic hypoglycaemia: two neonates without predisposing factors and a review of the literature

We report on transient hyperinsulinism (HI), presenting as severe congenital HI, in two neonates born without intrauterine growth restriction, maternal diabetes, perinatal asphyxia or Rhesus/platelet isoimmunisation. The neonates developed early (<6 h of life), symptomatic, non-ketotic hypoglycaemia (0–0.66 mmol/l), associated with elevated insulin levels (40–200 mU/l), and required high glucose infusion rates (22–24 mg/kg per min) to maintain normoglycaemia. However, both babies were diazoxide-sensitive and did not require glucose infusions beyond 2 weeks of life. Neither neonate had elevated serum ammonia levels or evidence of a metabolic disorder. Conclusion:transient hyperinsulinism can occur in newborns delivered uneventfully without significant perinatal complications. The unusual sensitivity to medical treatment in these cases of neonatal-onset hyperinsulinaemic hypoglycaemia underscores the importance of careful medical management of severe congenital hyperinsulinism. Careful consideration of the indication and if necessary, timing and extent of pancreatectomy is required, while maintaining euglycaemia to protect the developing brain.Abbreviations AGA appropriate for gestational age - BGL blood glucose level - BWS Beckwith-Wiedemann syndrome - HI hyperinsulinism - HI/HA hyperinsulinism/hyperammonaemia - IUGR intrauterine growth restriction - PHHI persistent hyperinsulinaemic hypoglycaemia of infancy - SGA small for gestational age - SUR sulphonylurea receptor - TNHI transient neonatal hyperinsulinism - UVC umbilical venous catheter     

From congenital hyperinsulinism to diabetes mellitus: the role of pancreatic beta-cell KATP channels

Pancreatic beta-cell adenosine triphosphate (ATP)-sensitive potassium (K(ATP)) channels play a pivotal role in linking glucose metabolism to regulated insulin secretion. K(ATP) channels are hetero-octameric complexes comprising two subunits Kir6.2 and sulfonylurea receptor 1 (SUR1). Changes in the intracellular concentration of nucleotides (ATP) cause alterations in the resting and opening state of the K(ATP) channels. Loss-of-function mutations in the genes encoding the two subunits of K(ATP) channels lead to the most common form of congenital hyperinsulinism (CHI). This causes persistent and severe hypoglycemia in the neonatal and infancy period. CHI can cause mental retardation and epilepsy if not treated properly. On the other hand, now there is evidence of an association between polymorphisms in the Kir6.2 gene and type 2 diabetes mellitus, mutations in the Kir6.2 gene and neonatal diabetes mellitus, and mutations in the SUR1 gene and diabetes mellitus. Interestingly, for reasons that are unclear at present, mice knockout models of K(ATP) channels are different from the human phenotype of CHI. This article is a review focusing on how abnormalities in the pancreatic beta-cell K(ATP) channels can lead to severe hypoglycemia on the one hand and diabetes mellitus on the other.     

Subtotal pancreatectomy for hypoglycemia due to congenital hyperinsulinism: long-term follow-up of neurodevelopmental and pancreatic function

Abstract: Objective: To evaluate neurodevelopmental status as well as endocrine and exocrine pancreatic function in children who have undergone subtotal pancreatectomy for hypoglycemia due to congenital hyperinsulinism. Patients and methods: Out of 15 identified patients, eight children (mean age 12.7 ± 0.8 yr) participated in detailed psychometric testing and studies assessing glucose homeostasis, secretion of proinsulin, insulin, glucagon and C‐peptide during a test meal. Additionally, a 24‐h fast, glucagon challenge test, 72‐h stool collection, and ultrasonography of the pancreatic remnant were performed. Results: Five of the 15 initially identified children had seizure disorders, including two with mental retardation. Diabetes developed in two of 15 children. All eight children investigated in the present study had evidence for attentional control impairment and 50% had subnormal intellectual functioning. Two had symptomatic hypoglycemia during the 24‐h fast, while one had an elevated fasting glucose concentration. Four children, including the latter patient, had proinsulin/insulin ratios resembling patients with type 2 diabetes. Exocrine pancreatic function was normal in all eight children. No correlation was found between pancreatic endocrine function and pancreatic remnant size, nor between multiple pre‐ and postoperative factors (i.e., age at diagnosis and surgery) and neurodevelopmental outcome. Conclusion: While severe mental retardation or diabetes occurred infrequently in our patient population compared with previous reports, all of the studied children had subtle anomalies in their cognitive performance tests and the majority had endocrine test results indicative of abnormal insulin secretion and stressed pancreatic β cells. Although partial pancreatectomy remains the treatment of choice after medical therapy fails, improved therapeutic means are necessary to achieve better clinical outcome.     

Congenital absence of the portal vein associated with focal nodular hyperplasia of the liver and cystic dysplasia of the kidney

Congenital absence of portal vein is a rare malformation. To date, 16 cases have been reported – all in association with other anomalies, i.e. benign or malignant hepatic neoplasms in 6 cases and cardiac malformations in 12. This case report described a girl with congenital absence of portal vein, focal nodular hyperplasia of the liver and cystic kidney dysplasia. Angiography showed the splenic vein and superior mesenteric vein joining to form a common trunk that entered the inferior vena cava directly above the liver. A review of the other cases in the literature is provided and the clinical aspects of our patient are discussed. Received: 3 December 1996 / Accepted in revised form: 9 September 1997     

Persistent hyperinsulinaemic hypoglycaemia in infancy

Persistent hyperinsulinaemic hypoglycaemia in infancy (PHHI) is a heterogeneous condition characterised by unregulated insulin secretion in response to a low blood glucose level. It is the most common cause of severe and persistent hypoglycaemia in neonates. It is extremely important to recognise this condition early and institute appropriate management to prevent significant brain injury leading to complications like epilepsy, cerebral palsy and neurological impairment. Histologically, PHHI is divided mainly into three types—diffuse, focal and atypical disease. Fluorine-18-l-3,4-dihydroxyphenylalanine positron emission tomography (18F-DOPA-PET/CT) scan allows differentiation between diffuse and focal diseases. The diffuse form is inherited in an autosomal recessive (or dominant) manner whereas the focal form is sporadic in inheritance and is localised to a small region of the pancreas. The molecular basis of PHHI involves defects in key genes (ABCC8, KCNJ11, GCK, SLC16A1, HADH, UCP2, HNF4A and GLUD1) that regulate insulin secretion. Focal lesions are cured by lesionectomy whereas diffuse disease (unresponsive to medical therapy) will require a near-total pancreatectomy with a risk of developing diabetes mellitus and pancreatic exocrine insufficiency. Open surgery is the traditional approach to pancreatic resection. However, recent advances in laparoscopic surgery have led to laparoscopic near-total pancreatectomy for diffuse lesions and laparoscopic distal pancreatectomy for focal lesions distal to the head of the pancreas.     

Congenital megalourethra

Megalourethra, a rare congenital disorder involving the anterior urethra, is subdivided into two types : Fusiform and scaphoid. Two cases of scaphoid type megalourethra are reported. The first patient, a 5-weeks-old infant diagnosed at birth as having the prune belly syndrome was admitted to the hospital with vomiting and failure to thrive. Intravenous pyelogram revealed marked dilatation of the left ureter and a bladder diverticulum. A penile urethrostomy was performed. The second patient, born to healthy parents after an uneventful pregnancy and delivery, was found to have an enlarged and deformed penis. The baby voided with a poor stream and a concomitant swelling of the penis was noted. Retrograde uretrography showed a sac-like dilatation of the penile urethra. Surgical revision was carried out a 2 stage procedure and was completed (Nesbitt's operation) after 4 months. The patient did well postoperatively and voided with a normal stream without any abnormality of the penile shaft.