Persistent hyperinsulinemic hypoglycemia of infancy ("nesidioblastosis"): autosomal recessive inheritance in 7 pedigrees

Late presentation of necrotizing enterocolitis associated with rotavirus infection in a term infant with hyperinsulinism on octreotide therapy: A case report

RATIONALE

Congenital hyperinsulinism (CHI) is the most common cause of persistent hypoglycemia in infancy that can cause permanent brain damage. Consequently, optimal management is extremely important. Current pharmacologic and surgical treatment were available that included diazoxide and octreotides.

PATIENT CONCERNS

A 4 month old Saudi male patient diagnosed at our hospital as CHI, treated with near total pancreatectomy and octreotide therapy of 30 mcg/kg/day presented with severe abdominal distension, vomiting and bloody diarrhea.

DIAGNOSES

The patient was diagnosed as necrotising enterocolitis (NEC) associated with Rota virus infection which played together with octeriotides as risk factors for NEC.

INTERVENTIONS

Radiological investigations and multidisciplinary team management with endocrinologist, neonatologist, pediatric surgeon, and gastroenterologist.

OUTCOMES

Resolution of NEC with conservative medical management and was discharged after 1 month of hospital stay with follow up with all concerned sub specialties.

LESSONS

NEC can develop in patients treated with octreotides especially when associated with another risk factor such as rotavirus infection.

Deciphering the fine-structure of tribal admixture in the Bedouin population using genomic data

The Bedouin Israeli population is highly inbred and structured with a very high prevalence of recessive diseases. Many studies in the past two decades focused on linkage analysis in large, multiple consanguineous pedigrees of this population. The advent of high-throughput technologies motivated researchers to search for rare variants shared between smaller pedigrees, integrating data from clinically similar yet seemingly non-related sporadic cases. However, such analyses are challenging because, without pedigree data, there is no prior knowledge regarding possible relatedness between the sporadic cases. Here, we describe models and techniques for the study of relationships between pedigrees and use them for the inference of tribal co-ancestry, delineating the complex social interactions between different tribes in the Negev Bedouins of southern Israel. Through our analysis, we differentiate between tribes that share many yet small genomic segments because of co-ancestry versus tribes that share larger segments because of recent admixture. The emergent pattern is well correlated with the prevalence of rare mutations in the different tribes. Tribes that do not intermarry, mostly because of social restrictions, hold private mutations, whereas tribes that do intermarry demonstrate a genetic flow of mutations between them. Thus, social structure within an inbred community can be delineated through genomic data, with implications to genetic counseling and genetic mapping.

Insulinoma-induced hypoglycemia in a patient with nesidiodysplasia after vagomotomy and pyloroplasty for duodenal ulcer

A 45-year-old woman was referred to us for hypoglycemia. The patient had been operated on for a duodenal ulcer by bilateral troncular vagotomy and pyloroplasty 20 years ago and, since then, she showed a dumping syndrome. Two months before consultation she developed repetitive episodes of symptomatic hypoglycemia. An oral glucose tolerance test showed hypoglycemia with endogenous hyperinsulinism. The continuous glucose monitoring system sensor demonstrated fasting hypoglycemia. The endoscopic ultrasound of the pancreas showed a pancreatic tumor that was confirmed in the pathologic study after surgery. Moreover, nesidiodysplasia image was found surrounding pancreatic parenchyma. We report, for the first time, both histologic lesions associated in a patient with a history of vagotomy and pyloroplasty for a duodenal ulcer and we discuss the possible pathogenic mechanisms.

Neonatal hyperinsulinism: clinicopathologic correlation

Neonatal hyperinsulinism is a life-threatening disease that, when treated by total pancreatectomy, leads to diabetes and pancreatic insufficiency. A more conservative approach is now possible since the separation of the disease into a nonrecurring focal form, which is cured by partial surgery, and a diffuse form, which necessitates total pancreas removal only in cases of medical treatment failure. The pathogenesis of the disease is now divided into K-channel disease (hyperinsulinemic hypoglycemia, familial [HHF] 1 and 2), which can mandate surgery, and other metabolic causes, HHF 3 to 6, which are treated medically in most patients. The diffuse form is inherited as a recessive gene on chromosome 11, whereas most cases of the focal form are caused by a sulfonylurea receptor 1 defect inherited from the father, which is associated with a loss of heterozygosity on the corresponding part of the mother's chromosome 11. The rare bifocal forms result from a maternal loss of heterozygosity specific to each focus. Paternal disomy of chromosome 11 is a rare cause of a condition similar to Beckwith-Wiedemann syndrome. A preoperative PET scan with fluorodihydroxyphenylalanine and perioperative frozen-section confirmation are the types of studies done before surgery when needed. Adult variants of the disease are less well defined at the present time.

Early brain atrophy in persistent hyperinsulinemic hypoglycemia of infancy

We present two siblings with persistent hyperinsulinemic hypoglycemia of infancy, accelerated intrauterine growth and early neonatal brain atrophy. Fetal plasma glucose and insulin levels in the second sibling revealed normoglycemia despite hyperinsulinemia. The absence of intrauterine hypoglycemia suggests that the brain damage is not secondary to hypoglycemia and other etiologies must be considered.

Molecular basis of autosomal recessive diseases among the Palestinian Arabs

In the review of the literature, 71 different autosomal recessive diseases have been delineated that are relatively frequent among Palestinian Arabs. Among those, in 40 the mutation(s) responsible for the diseases are known. Fourteen of these disorders were caused by a single mutation, while the other 26 were due to multiple mutations. Most of the mutations were found in homozygosity among the affected patients. It is probable that the high frequency of most of the genetic diseases among the Palestinian Arabs is due to a founder effect as the result of the high consanguinity rates in this population. However, in some cases the high frequency was demonstrated to be secondary to the presence of multiple mutations, either allelic or in different genes in a small geographic region. This phenomenon remains unexplained but may be secondary to a selective advantage to the carriers, either specific to the region or to the population.

Histologic findings in persistent hyperinsulinemic hypoglycemia of infancy: Australian experience

Persistent hyperinsulinemic hypoglycemia of infancy (PHHI) is characterized by hyperinsulinism and profound hypoglycemia, with most children requiring pancreatic resection. The histological classification of PHHI is controversial. Most authors acknowledge the existence of focal areas of islet cell proliferation (adenomatosis) in 30%-50% of cases and a diffuse disorganisation of islet architecture, termed "nesidiodysplasia," in others. De Lonlay et al. reported that cases with adenomatosis are focal with normal remainder of pancreas and that focal and diffuse disease can be differentiated intraoperatively, on the basis of increased beta-cell nuclear size found only in the diffusely abnormal pancreas. We have examined pancreatic histology in a blinded controlled study of PHHI patients. Pancreatic tissue was obtained at autopsy from 60 normal subjects (age 17 weeks gestation to 76 years) and from surgical specimens of 31 PHHI patients. Sections from PHHI subjects (n = 294 blocks) and control sections were stained with hematoxylin and eosin, insulin, glucagon, somatostatin, NSE, cytokeratin 19, and vimentin. Three sections from each PHHI patient were randomly chosen for further analysis. Age-matched control (n = 34) and PHHI sections (n = 66) were examined, with the identity of subjects concealed. A diagnosis of normal histology, adenomatosis, or diffuse nesidiodysplasia was recorded for each section. The presence of large beta-cell nuclei (>19 microm), ductuloinsular complexes, and centroacinar cell proliferation was noted. Of a total of 65 subjects examined (34 control and 31 PHHI), 37 subjects were identified as normal on both sections examined. All the control cases were correctly identified as normal and none had large beta-cell nuclei or centroacinar cell proliferation. Of 31 PHHI patients, 28 were identified as abnormal, either on the basis of abnormal architecture and/or abnormally large beta-cell nuclei. Three patients were identified as normal in both sections. Fifteen of 31 patients had diffuse nesidiodysplasia only. Of 13 patients with areas of adenomatosis, 2 had resection of a nodule with adenomatosis present in most of the tissue removed at surgery. Nine patients had a diagnosis of adenomatosis in one section and a diagnosis of diffuse nesidiodysplasia in the other sections from nonadjacent pancreas. Only 2 of 31 PHHI cases had adenomatosis on one section examined and normal pancreas on the other section examined. Large beta-cell nuclei were variably found in PHHI sections. Only 5 of 15 patients with diffuse nesidiodysplasia had large nuclei in both sections examined. Centroacinar cell proliferation was identified in 12 PHHI subjects, 6 with adenomatosis and diffuse nesidiodysplasia and 6 with diffuse changes only. It was patchy in distribution within sections and present in only one section in 7 of the 12 subjects. In summary, we have shown that a blinded observer could differentiate control and PHHI pancreatic tissue. Only 2 of 31 patients (6%) had focal adenomatosis with normal nonadjacent pancreas, the majority (24 of 31) had diffuse nesidiodysplasia affecting the remainder of their pancreas, with 38% (9 of 24) also having areas of adenomatosis. Large beta-cell nuclei did not reliably identify those with diffuse disease in this study. There was evidence of significant ductal and centroacinar proliferation in 39% of PHHI cases, which was not observed in any of the controls. We have shown that PHHI subjects have a spectrum of pancreatic histological abnormalities, from no abnormality to diffuse subtle changes to florid adenomatosis. Patients could not be segregated into subtypes for different operative intervention despite the availability of full immunohistochemical staining.

Congenital hyperinsulinism: molecular basis of a heterogeneous disease

Congenital hyperinsulinism (CHI) is a disease phenotype characterized by increased, usually irregular, insulin secretion leading to hypoglycemia, coma, and severe brain damage, left untreated. Hyperinsulinism may be caused by a range of biochemical disturbances and molecular defects. In pancreatic beta cells, insulin secretion is stimulated by closure of the ATP-dependent potassium channel (K(ATP) channel). K(ATP) channel is a complex composed of at least two subunits: the sulfonylurea receptor SUR1 and Kir6.2, an inward rectifier K+ channel member. Mutations in both subunits have been identified in patients with the autosomal recessive form of hyperinsulinism, including 28 different mutations in the SUR1 gene and two mutations in the Kir6.2 gene. These mutations co-segregated with disease phenotype, also known as persistent hyperinsulinemic hypoglycemia of infancy (PHHI), and with attenuated K(ATP) channel function. Inadequately high insulin secretion in one family with an autosomal dominant mode of inheritance is caused by a mutation in the glucokinase gene, resulting in increased affinity of the enzyme for glucose. Five different mutations have been identified in the glutamate dehydrogenase gene, resulting in overactivity of this enzyme and causing a syndrome of hyperinsulinism and hyperammonemia. In 13 cases, hyperinsulinism was caused by one or more focal pancreatic lesions with specific loss of maternal alleles of the imprinted chromosome region 11p15. In five patients, this loss of heterozygosity unmasked a paternally inherited recessive SUR1 mutation. The new molecular approaches in PHHI give further insight into the mechanism of pancreatic beta cell insulin secretion. The heterogeneous group of patients with CHI may now be classified according to their basic defects in the four different genes, with potential implications for a more specific treatment.

Hyperinsulinism of the newborn

Neonatal hyperinsulinism (HI) is a clinical syndrome of pancreatic beta-cell dysfunction characterized by failure to suppress insulin secretion in the presence of hypoglycemia. Although rare, it is the most common cause for persistent hypoglycemia in the newborn period. Treatment can be extremely difficult, and partial pancreatectomy is frequently required to prevent recurrent hypoglycemia and irreversible brain damage. In the last 5 years much has been learned about the pathophysiology of this disease. In most patients, the disease is caused by recessive mutations in either of the 2 functional subunits of the beta-cell KATP channel (SUR1 or Kir6.2). Although in most families, the disease is transmitted as an autosomal recessive trait, a novel form of transmission, resulting in focal involvement of the pancreas has recently been described. Not all patients with HI have mutations in the KATP channel genes. An activating mutation in the "glucose sensor" glucokinase has recently been reported in one family with diazoxide-responsive autosomal dominant hyperinsulinemic hypoglycemia. Also, a new syndrome of hyperinsulinism associated with benign hyperammonemia was recently described and found to be caused by activating mutations in the glutamate dehydrogenase (GDH) gene (GLUD-1). Thus, the clinical syndrome of HI can be caused by mutations in 4 different genes and can be transmitted as either a recessive or a dominant trait. These findings aid in the therapeutic decision-making process and improve the accuracy and precision of genetic counseling. Despite these recent discoveries, however, the metabolic origin of the disease is still unknown in about 50% of cases.

Genetics of neonatal hyperinsulinism

Congenital hyperinsulinism (HI) is a clinically and genetically heterogeneous entity. The clinical heterogeneity is manifested by severity ranging from extremely severe, life threatening disease to very mild clinical symptoms, which may even be difficult to identify. Furthermore, clinical responsiveness to medical and surgical management is extremely variable. Recent discoveries have begun to clarify the molecular aetiology of this disease and thus the mechanisms responsible for this clinical heterogeneity are becoming more clear. Mutations in 4 different genes have been identified in patients with this clinical syndrome. Most cases are caused by mutations in either of the 2 subunits of the beta cell ATP sensitive K(+) channel (K(ATP)), whereas others are caused by mutations in the beta cell enzymes glucokinase and glutamate dehydrogenase. However, for as many as 50% of the cases, no genetic aetiology has yet been determined. The study of the genetics of this disease has provided important new information about beta cell physiology. Although the clinical ramifications of these findings are still limited, in some situations genetic studies might greatly aid in patient management.

Genetic mutations as a cause of hyperinsulinemic hypoglycemia in children

Hyperinsulinemic hypoglycemia in children is associated with unregulated secretion of insulin and hypoglycemia, a condition that is now known to be genetically diverse. This article reviews recent progress that has elucidated several beta-cell molecular defects responsible for the pathogenesis of this disorder.

Persistent hyperinsulinaemic hypoglycaemia of infancy (nesidioblastosis): a report from Kuwait

We report nine Bedouin children from Kuwait with persistent hyperinsulinaemic hypoglycaemia (PHHI) seen over a 13-year period in two regional hospitals. The incidence of PHHI in this inbred community is high (1:20,000); five of them came from two families. All the children presented with seizures associated with severe and recurrent hypoglycaemia, eight presenting in the neonatal period and one at the age of 2 months. One child died soon after birth. All the others received diazoxide initially, which achieved remission in one while two siblings remain dependent on the drug. Long-acting somatostatin analogue (octreotide) was successfully used in one child. Four children underwent pancreatectomy, two showed diffuse and two had localized nesidioblastosis. Two children achieved normal neurodevelopmental milestones, four suffered mental retardation of varying degrees and three died. Early diagnosis and prompt treatment are essential to avoid the neurological damage associated with hypoglycaemia. In some cases, this condition is due to an autosomal recessive pattern of inheritance and it is therefore important to offer genetic counselling to families with one or more affected siblings.

Neonatal Hyperinsulinism

Hypoglycemia as a result of hyperinsulinism in the newborn (HI) is a clinically heterogeneous entity that presents a diagnostic and therapeutic challenge to the treating physician. Recent discoveries have shown that mutations in four different beta-cell genes cause HI. However, for many HI patients, the molecular etiology is unknown, and other genes might be involved. The study of the molecular biology of HI has led to a better understanding of pancreatic beta-cell physiology. In the future, this might result in the development of novel drugs for the treatment of both hyperinsulinism and non-insulin-dependent diabetes.

[Persistent hyperinsulinemic hypoglycemia in the newborn and infants]

Persistent hyperinsulinemic hypoglycaemia of infancy (PHHI) is the most frequent cause of hypoglycaemia in infancy. Clinical presentation is heterogeneous, with variable onset of hypoglycaemia and response to diazoxide, and presence of sporadic or familial forms. Underlying histopathological lesions can be focal or diffuse. Focal lesions are characterised by focal hyperplasia of pancreatic islet-like cells, whereas diffuse lesions implicate the whole pancreas. The distinction between the two forms is important because surgical treatment and genetic counselling are radically different. Focal lesions correspond to somatic defects which are totally cured by limited pancreatic resection, whereas diffuse lesions require a subtotal pancreatectomy exposing to high risk of diabetes mellitus. Diffuse lesions are due to functional abnormalities involving several genes and different transmission forms. Recessively inherited PHHI have been attributed to homozygote mutations for the beta-cell sulfonylurea receptor (SUR1) or the inward-rectifying potassium-channel (Kir6.2) genes. Dominantly inherited PHHI can implicate the glucokinase gene, particularly when PHHI is associated with diabetes, the glutamate dehydrogenase gene when hyperammonaemia is associated, or another locus.

Familial hyperinsulinism with apparent autosomal dominant inheritance: clinical and genetic differences from the autosomal recessive variant

We describe three families with hypoglycemia caused by familial hyperinsulinism (HI) in whom vertical transmission of the disorder occurred, suggesting autosomal dominant (AD) inheritance. We therefore examined the relationship between the apparent AD disorder and the more common autosomal recessive (AR) form of HI, which has recently been linked to the sulfonylurea receptor on chromosome 11p15.1. The clinical features of the 11 patients with AD HI were milder than those seen in 14 patients with AR HI. Hypoglycemia was readily controlled with either diet alone or with diazoxide in 10 of 11 patients with AD HI but in none of those with the AR form. In one large pedigree, analysis of genomic DNA with polymorphic simple sequence repeat markers excluded linkage of AD HI to the SUR locus in a dominant manner. The possibility of linkage to the SUR locus could not be absolutely excluded in the two smaller pedigrees. None of the published mutations of the SUR gene identified in patients with AR HI were detected in the patients with the AD form. We conclude that the AD form of hyperinsulinism is phenotypically different from the AR variant. The identification of more families with this form of HI may make it possible to locate the responsible gene by the use of linkage analysis.

Somatic deletion of the imprinted 11p15 region in sporadic persistent hyperinsulinemic hypoglycemia of infancy is specific of focal adenomatous hyperplasia and endorses partial pancreatectomy

Sporadic persistent hyperinsulinemic hypoglycemia of infancy (PHHI) or nesidioblastosis is a heterogeneous disorder characterized by profound hypoglycemia due to inappropriate hypersecretion of insulin. An important diagnostic goal is to distinguish patients with a focal hyperplasia of islet cells of the pancreas (FoPHHI) from those with a diffuse abnormality of islets (DiPHHI) because management strategies differ significantly. 16 infants with sporadic PHHI resistant to diazoxide and who underwent pancreatectomy were investigated. Selective pancreatic venous sampling coupled with peroperative surgical examination and analysis of extemporaneous frozen sections allowed us to identify 10 cases with FoPHHI and 6 cases with DiPHHI. We show here that in cases of FoPHHI, but not those of DiPHHI, there was specific loss of maternal alleles of the imprinted chromosome region 11p15 in cells of the hyperplastic area of the pancreas but not in normal pancreatic cells. This somatic event is consistent with a proliferative monoclonal lesion. It involves disruption of the balance between monoallelic expression of several maternally and paternally expressed genes. Thus, we provide the first molecular explanation of the heterogeneity of sporadic forms of PHHI such that it is possible to perform only partial pancreatectomy, limited to the focal somatic lesion, so as to avoid iatrogenic diabetes in patients with focal adenomatous hyperplasia.

A syndrome of congenital hyperinsulinism and hyperammonemia

This report describes two patients from unrelated families with an unusual syndrome of hyperinsulinism plus hyperammonemia. The diagnosis of hyperinsulinism was based on the demonstration of fasting hypoglycemia with inappropriately elevated insulin levels, inappropriately low beta-hydroxybutyrate and free fatty acid levels, and inappropriately large glycemic response to the administration of glucagon. In both patients, plasma ammonium levels were persistently elevated and unaffected by protein feeding, protein restriction, or benzoate therapy. Plasma and urinary amino acids, urinary organic acids, and urinary orotic acid levels were not consistent with any of the urea cycle enzyme defects or other hyperammonemic disorders. These two patients appear to represent a unique form of congenital hyperinsulinism distinct from the previously described autosomal dominant and autosomal recessive variants. We speculate that the underlying defect involves a site that is common to the amino acid regulation of both insulin secretion in pancreatic beta-cells and urea synthesis in the liver.

Persistent hyperinsulinemic hypoglycemia of infancy: experience with 28 cases

Twenty-eight infants with persistent hyperinsulinemic hypoglycemia of infancy (PHHI) were seen during a 10-year period. There were 13 males and 15 females. Their age at time of presentation ranged from a few hours to 6 months. Consanguinity was reported in 20 cases (71.4%). One family had two affected siblings and two affected cousins, another had three affected siblings and one affected cousin, and three others had lost siblings because of hypoglycemia and seizures. The primary clinical presentation was jitters and seizures in association with hypoglycemia. The diagnosis was suspected when the therapeutic glucose requirement was found to be more than 12 mg/kg/min and also when there was a good response to glucagon after exclusion of metabolic and storage diseases. A high insulin-to-glucose ratio was noted for all patients. Twenty-two had near-total (90%) pancreatectomy; the result was excellent in all but four, who required supplemental medical therapy. Five patients were treated medically, and one patient's family refused treatment. Twelve patients sustained moderate to severe brain injury before referral. There were no deaths, and only one patient had evidence of malabsorption after the pancreatectomy. PHHI correlates well with consanguinity and family history. Clinical awareness is essential to permit early diagnosis and prompt medical and supportive therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Familial hyperinsulinism maps to chromosome 11p14-15.1, 30 cM centromeric to the insulin gene

Familial hyperinsulinism (HI) is the most common cause of persistent neonatal hyperinsulinaemic hypoglycemia. Linkage analysis in 15 families (12 Ashkenazi Jewish, 2 consanguineous Arab, 1 non-Jewish Caucasian) mapped HI to chromosome 11p14-15.1 (lod score = 9.5, theta = 0 at D11S921). Recombinants localized the disease locus to the 6.6 cM interval between D11S926 and D11S928. In Jewish families, association (p = 0.003) with specific D11S921/D11S419 haplotypes suggested a founder effect. This locus, which is important for normal glucose-regulated insulin secretion, represents a candidate gene for studies of other diseases of beta-cell dysfunction including non-insulin-dependent diabetes mellitus (NIDDM).

Familial nesidioblastosis: more evidence for autosomal recessive inheritance

Severe neonatal hypoglycaemia in five Saudi Arab infants of both sexes belonging to two families of consanguineous parents is reported. All of these infants needed sub-total pancreatectomy to maintain normoglycaemia. Histopathological studies with immunohistochemistry proved diffuse nesidioblastosis of the pancreas in all five infants. Data obtained from these families and other families reported in the literature strongly suggest that familial nesidioblastosis is an autosomal recessive disorder. Knowledge of the inheritance pattern is important both for genetic counselling and for making a prompt diagnosis in subsequently affected siblings, as delay in appropriate treatment may have serious consequences.