Yves Aigrain

Congenital hyperinsulinism: current trends in diagnosis and therapy

Congenital hyperinsulinism (HI) is an inappropriate insulin secretion by the pancreatic β-cells secondary to various genetic disorders. The incidence is estimated at 1/50, 000 live births, but it may be as high as 1/2, 500 in countries with substantial consanguinity. Recurrent episodes of hyperinsulinemic hypoglycemia may expose to high risk of brain damage. Hypoglycemias are diagnosed because of seizures, a faint, or any other neurological symptom, in the neonatal period or later, usually within the first two years of life. After the neonatal period, the patient can present the typical clinical features of a hypoglycemia: pallor, sweat and tachycardia. HI is a heterogeneous disorder with two main clinically indistinguishable histopathological lesions: diffuse and focal. Atypical lesions are under characterization. Recessive ABCC8 mutations (encoding SUR1, subunit of a potassium channel) and, more rarely, recessive KCNJ11 (encoding Kir6.2, subunit of the same potassium channel) mutations, are responsible for most severe diazoxide-unresponsive HI. Focal HI, also diazoxide-unresponsive, is due to the combination of a paternally-inherited ABCC8 or KCNJ11 mutation and a paternal isodisomy of the 11p15 region, which is specific to the islets cells within the focal lesion. Genetics and 18F-fluoro-L-DOPA positron emission tomography (PET) help to diagnose diffuse or focal forms of HI. Hypoglycemias must be rapidly and intensively treated to prevent severe and irreversible brain damage. This includes a glucose load and/or a glucagon injection, at the time of hypoglycemia, to correct it. Then a treatment to prevent the recurrence of hypoglycemia must be set, which may include frequent and glucose-enriched feeding, diazoxide and octreotide. When medical and dietary therapies are ineffective, or when a focal HI is suspected, surgical treatment is required. Focal HI may be definitively cured when the partial pancreatectomy removes the whole lesion. By contrast, the long-term outcome of diffuse HI after subtotal pancreatectomy is characterized by a high risk of diabetes, but the time of its onset is hardly predictable.

Cultural Bias in the AAP’s 2012 Technical Report and Policy Statement on Male Circumcision

The American Academy of Pediatrics recently released its new Technical Report and Policy Statement on male circumcision, concluding that current evidence indicates that the health benefits of newborn male circumcision outweigh the risks. The technical report is based on the scrutiny of a large number of complex scientific articles. Therefore, while striving for objectivity, the conclusions drawn by the 8 task force members reflect what these individual physicians perceived as trustworthy evidence. Seen from the outside, cultural bias reflecting the normality of nontherapeutic male circumcision in the United States seems obvious, and the report’s conclusions are different from those reached by physicians in other parts of the Western world, including Europe, Canada, and Australia. In this commentary, a different view is presented by non–US-based physicians and representatives of general medical associations and societies for pediatrics, pediatric surgery, and pediatric urology in Northern Europe. To these authors, only 1 of the arguments put forward by the American Academy of Pediatrics has some theoretical relevance in relation to infant male circumcision; namely, the possible protection against urinary tract infections in infant boys, which can easily be treated with antibiotics without tissue loss. The other claimed health benefits, including protection against HIV/AIDS, genital herpes, genital warts, and penile cancer, are questionable, weak, and likely to have little public health relevance in a Western context, and they do not represent compelling reasons for surgery before boys are old enough to decide for themselves.

ABCC8 and KCNJ11 molecular spectrum of 109 patients with diazoxide-unresponsive congenital hyperinsulinism

Background Congenital hyperinsulinism (CHI) is characterised by an over secretion of insulin by the pancreatic β-cells. This condition is mostly caused by mutations in ABCC8 or KCNJ11 genes encoding the SUR1 and KIR6.2 subunits of the ATP-sensitive potassium (KATP) channel. CHI patients are classified according to their responsiveness to diazoxide and to their histopathological diagnosis (either focal, diffuse or atypical forms). Here, we raise the benefits/limits of the genetic diagnosis in the clinical management of CHI patients. Methods ABCC8/KCNJ11 mutational spectrum was established in 109 diazoxide-unresponsive CHI patients for whom an appropriate clinical management is essential to prevent brain damage. Relationships between genotype and radiopathological diagnosis were analysed. Results ABCC8 or KCNJ11 defects were found in 82% of the CHI cases. All patients with a focal form were associated with a single KATP channel molecular event. In contrast, patients with diffuse forms were genetically more heterogeneous: 47% were associated with recessively inherited mutations, 34% carried a single heterozygous mutation and 19% had no mutation. There appeared to be a predominance of paternally inherited mutations in patients diagnosed with a diffuse form and carrying a sole KATP channel mutation. Conclusions The identification of recessively inherited mutations related to severe and diffuse forms of CHI provides an informative genetic diagnosis and allows prenatal diagnosis. In contrast, in patients carrying a single KATP channel mutation, genetic analysis should be confronted with the PET imaging to categorise patients as focal or diffuse forms in order to get the appropriate therapeutic management.

Morphological Mosaicism of the Pancreatic Islets: A Novel Anatomopathological Form of Persistent Hyperinsulinemic Hypoglycemia of Infancy

BACKGROUNDnMorphological studies of the pancreas in persistent hyperinsulinemic hypoglycemia of infancy (PHHI) have focused on the diagnosis of focal vs. diffuse forms, a distinction that determines the optimal surgical management. ABCC8 or KCNJ11 genomic mutations are present in most of them.nnnAIMnOur aim was to report a new form of PHHI with peculiar morphological and clinical characteristics.nnnRESEARCH DESIGN AND METHODSnHistopathological review of 217 pancreatic PHHI specimens revealed 16 cases morphologically different from diffuse and focal forms. They were analyzed by conventional microscopy, quantitative morphometry, immunohistochemistry, and in situ hybridization.nnnRESULTSnTheir morphological peculiarity was the coexistence of two types of islet: large islets with cytoplasm-rich β-cells and occasional enlarged nuclei and shrunken islets with β-cells exhibiting little cytoplasm and small nuclei. In small islets, β-cells had abundant insulin content but limited amount of Golgi proinsulin. Large islets had low insulin storage and high proinsulin production and were mostly confined to a few lobules. No evidence for K(ATP) channels involvement or 11p15 deletion was found. Genomic mutations for ABCC8, KCNJ11, and GCK were absent. Patients had normal birth weight and late hypoglycemia onset and improved with diazoxide. Ten were cured by limited pancreatectomy. Six recurred after surgery and were medically controlled.nnnCONCLUSIONnThis new form of PHHI is characterized by a morphological mosaicism. Pathologists should recognize this mosaicism on intraoperative frozen sections because it is often curable by partial pancreatectomy. The currently unknown genetic background does not involve the classical genomic mutations responsible for diffuse and focal PHHI.

Up-to-date evolution of small bowel transplantation in children with intestinal failure

PURPOSEnThe aim of the authors was to report an up-to-date review of their experience with 26 intestinal transplantations in children since 1987.nnnMETHODSnA retrospective study was conducted of 26 patients with a mean age of 5 years (range, 0.3 to 14 years). Three groups were isolated. In group A (1987 to 1990), seven patients received nine isolated intestinal transplants for short bowel syndrome. Immunosuppression therapy consisted of cyclosporine, aziathioprine, and corticosteroids. In group B (1994-current), nine patients received nine isolated intestinal transplants for short bowel syndrom (n = 2), intestinal pseudoobstruction (n = 2), neonatal intractable diarrhea (n = 3), and Hirschsprung disease (n = 1); hepatic biopsy results showed weak cholestasis or fibrosis. In group C (1994-current), 10 patients received 10 combined liver-small bowel transplants for short bowel syndrome (n = 3), neonatal intractable diarrhea (n = 4), and Hirschsprung disease (n = 3); hepatic cirrhosis related to total parenteral nutrition (TPN) was shown in all cases. Groups B and C received immunosupressive treatment consisting of tacrolimus, aziathioprine, and corticosteroids. Posttransplant follow-up included intestinal biopsies of the small bowel twice a week and more frequently or combined with liver biopsy if rejection was suspected.nnnRESULTSnOverall patient survival (PS) and graft survival (GS) are 61% (16 of 26) and 50% (13 of 26), respectively. In group A, severe intestinal allograft rejection occurred in six patients leading to graft removal (GS, 11%). Five patients died of TPN complications after graft removal (PS, 28%). One survivor is off TPN, and one currently is waiting for a second graft. In group B, six patients survived (PS, 66%). Causes of death include hepatic failure (n = 1), renal and liver failure (n = 1), and systemic infection (n = 1). Severe intestinal allograft rejection occurred in five patients, which neccessitated aggressive immunosuppression (antilymphocyte serum) leading to an incomplete functional recovery of the graft. Only two patients currently are off TPN. In group C, eight patients survived (PS, 80%) all of which are currently off TPN. One patient died during the procedure, and one died of severe systemic infection. Intestinal graft rejection occurred in six patients; rejection of the liver allograft occurred in five patients, yet all rejections were weak and successfully treated by corticosteroids (GS, 80%).nnnCONCLUSIONSnIntestinal transplantation is a valid therapeutic option for children with definitive intestinal failure and not only for short bowel syndrome. Tacrolimus improves graft and patient survival (group A v group B). The lower severity of graft rejection in combined liver-small bowel transplantation improves functional results of intestinal transplantation in children without additional mortality or morbidity (group B vgroup C).

Value of 18F–fluoro-l-dopa PET in the Preoperative Localization of Focal Lesions in Congenital Hyperinsulinism

PURPOSEnTo retrospectively compare fluorine 18 ((18)F) fluoro-L-dopa positron emission tomography (PET) and pancreatic venous sampling (PVS) in the preoperative differentiation of diffuse from focal congenital hyperinsulinism (CHI) and localization of focal lesions.nnnMATERIALS AND METHODSnThis study was approved by the institutional ethical committee, and informed consent for the research study was obtained from the parents of all subjects. Fifty-one patients evaluated for focal CHI between January 1, 1995, and January 31, 2008, were included. Thirty five underwent PVS evaluation alone, and 16 underwent a PET evaluation alone. The sensitivity values of each technique for the diagnosis and localization of focal lesions were compared in regard to results of surgery and pathologic analyses. In each patient, perioperative treatment was reviewed, and the presence of postoperative hypoglycemia was assessed as evidence of incomplete resection. Comparisons of the sensitivity values and recurrence rates were performed by using the Fisher exact test in regard to the number of patients. Comparisons of median age, weight, or number of biopsies were performed with a two-tailed unpaired Mann-Whitney U test. A difference with P < .05 was considered significant.nnnRESULTSnFor PVS and PET groups, there was no error in differentiating focal from diffuse forms. PVS was not completed in four of 35 patients. In 27 (87%) of 31 patients in whom PVS was completed and 13 (81%) of 16 patients in whom PET was completed, preoperative localization of the focal lesion was in accordance with the surgical findings (P = .7). Although not significant, the number of biopsies performed before discovering the focal lesion was higher in the PET group compared with the PVS group (P = .06). Inadequate localization occurred in two (6%) patients in the PVS group and five (31%) patients in the PET group at initial preoperative imaging study; these patients underwent repeat surgery for residual CHI (P = .03).nnnCONCLUSIONn(18)F-fluoro-L-dopa PET is equivalent to PVS in the characterization of CHI but does not provide localization of the lesion as precisely as does PVS.

Renal transplantation in 4 patients with methylmalonic aciduria: A cell therapy for metabolic disease

INTRODUCTIONnPatients with methylmalonic acidemia (MMA) may develop many complications despite medical treatment, in particular, severe central nervous system damage and chronic kidney disease (CKD). A kidney transplant may partially correct the metabolic dysfunctions. Liver, kidney and combined liver-kidney transplantations have been advocated but no guidelines are available to identify the most suitable organ to transplant.nnnPATIENTS AND METHODSnFour patients with MMA (mut° phenotype) received a kidney graft because of repeated metabolic decompensations, with progression to CKD in 3 patients (end-stage kidney disease in two patients and CKD stage III in one patient with an estimated glomerular filtration rate [eGFR] of 40ml/min/1.73m(2)) but normal renal function in one (eGFR of 93ml/min/1.73m(2)) before transplantation.nnnRESULTSnThe medium age at transplantation was 7.9y (5-10.2) and the median follow-up was 2.8years (1.8-4.6). Renal transplantation improved the relevant metabolic parameters in 4/4 patients and renal function in the patients with CKD. Plasma and urinary MMA levels immediately decreased and remained normal or subnormal (mean values of plasma MMA before transplantation 1530μmol/L versus 240μmol/L after transplantation, and mean values of urine MMA before transplantation 4700mmol/mol creatinine versus 2300mmol/mol creatinine after transplantation). No further acute metabolic decompensation was observed and protein-intake was increased from 0.60 to 0.83g/Kg/day. One patient transplanted at age 9.7years developed a hepatoblastoma at age 11years with subsequent neurological complications and eventually died. The three other patients are alive. Two of them remained neurologically stable. The 3rd patient who displayed choreoathetosis transiently improved his neurological condition immediately after transplantation and then remained stable.nnnCONCLUSIONnKidney transplantation represents an interesting alternative therapeutic option in methylmalonic aciduria, for renal complications but also as a cellular therapy that may significantly reduce metabolic decompensations and hospitalizations. However, further neurological impairment remains possible.

Prenatal management of disorders of Sex development

Disorders of sex development (DSD) rarely present prenatally but, as they are very complex conditions, management should be directed by highly specialised medical teams to allow consideration of all aspects of diagnosis, treatment and ethical issues. In this brief review, we present an overview of the prenatal presentation and management of DSD, including the sonographic appearance of normal genitalia and methods of determining genetic sex, the prenatal management of pregnancies with the unexpected finding of genital ambiguity on prenatal ultrasound and a review of the prenatal management of pregnancies at high risk of DSD. As this is a rapidly developing field, management options will change over time, making the involvement of clinical geneticists, paediatric endocrinologists and urologists, as well as fetal medicine specialists, essential in the care of these complex pregnancies. The reader should also bear in mind that local social, ethical and legal aspects may also influence management.

Familial Focal Congenital Hyperinsulinism

This report describes focal congenital hyperinsulinism in siblings, and genetic counseling is recommended for this rare disease.

Preoperative Wilms tumor rupture: a retrospective study of 57 patients.

According to current International Society of Pediatric Oncology (SIOP) Wilms recommendations, all preoperative tumor ruptures should be classified as stage IIIc. However, to the authors knowledge, the definition and diagnostic criteria of preoperative rupture have not been defined clearly.