Coronary-cameral fistula with double-chambered right ventricle: appearance on cardiac magnetic resonance imaging and 3D printed anatomic modeling

The present case illustrates cardiac magnetic resonance imaging (MRI) and three-dimensional (3D) printed anatomic model findings of a coronary-cameral fistula (CCF) and double-chambered right ventricle (DCRV). A pregnant woman presented with palpitations and near syncope. A non-contrast cardiac MRI showed CCF connecting to a DCRV. Post-delivery, the patient had a contrast-enhanced MRI and 3D printed anatomic model to better evaluate her aberrant anatomy.

Pregnancy after Aortic Root Replacement in Marfan's Syndrome: A Case Series and Review of the Literature

Objectives  We sought to characterize pregnancy-related aortic complications in women with Marfan's syndrome who had prior aortic root replacement. Study Design  This is a retrospective case series study and literature review of women with Marfan's syndrome with pregnancy after aortic root replacement. We surveyed women with Marfan's syndrome who had successful pregnancy after aortic root replacement using the Marfan Foundation Website and from two large tertiary care Marfan's clinics. Clinical data, counseling information, and details of pregnancy-related aortic complications were compiled. A literature review was performed assessing aortic outcomes in women with Marfan's syndrome with pregnancy after aortic surgery. Results  Fourteen women with 20 pregnancies were identified. Two women had three pregnancies following root replacement for aortic dissection. There were no aortic dissections during the 20 pregnancies. In contrast, aortic dissection was frequently reported in the literature. Conclusions  Women with Marfan's syndrome who become pregnant following aortic root replacement remain at risk for distal aortic dissection related to pregnancy. The exact risk is difficult to quantify but is not zero and women should be counseled accordingly.

Hypertension Across a Woman's Life Cycle

Hypertension accounts for 1 in 5 deaths among American women, posing a greater burden for women than men, and is among their most important risk factors for death and development of cardiovascular and other diseases. Hypertension affects women in all phases of life, with specific characteristics relating to risk factors and management for primary prevention of hypertension in teenage and young adult women; hypertension in pregnancy; hypertension during use of oral contraceptives and assisted reproductive technologies, lactation, menopause, or hormone replacement; hypertension in elderly women; and issues of race and ethnicity. All are detailed in this review, as is information relative to women in clinical trials of hypertension and medication issues. The overarching message is that effective treatment and control of hypertension improves cardiovascular outcomes. But many knowledge gaps persist, including the contribution of hypertensive disorders of pregnancy to cardiovascular disease risk, the role of hormone replacement, blood pressure targets for elderly women, and so on.

Impact of pregnancy on autograft dilatation and aortic valve function following the Ross procedure

OBJECTIVE

The effects of pregnancy on autograft dilatation and neoaortic valve function in patients with a Ross procedure have not been studied. We sought to evaluate the effect of pregnancy on autograft dilatation and valve function in these patients with the goal of determining whether pregnancy is safe after the Ross procedure.

DESIGN

A retrospective chart review of female patients who underwent a Ross procedure was conducted.

PATIENTS

Medical records for 51 patients were reviewed. Among the 33 patients who met inclusion criteria, 11 became pregnant after surgery and 22 did not.

OUTCOME MEASURES

Echocardiographic reports were used to record aortic root diameter and aortic insufficiency before, during, and after pregnancy. Patient's charts were reviewed for reinterventions and complications. Primary endpoints included reinterventions, aortic root dilation of ≥5 cm, aortic insufficiency degree ≥ moderate, and death.

RESULTS

There were 18 pregnancies carried beyond 20 weeks in 11 patients. There was no significant difference in aortic root diameter between nulliparous patients and parous patients prior to their first pregnancy (3.53 ± 0.44 vs 3.57 ± 0.69 cm, P = .74). There was no significant change in aortic root diameter after first pregnancy (3.7 ± 0.4 cm, P = .056) although there was significant dilatation after the second (4.3 ± 0.7 cm, P = .009) and third (4.5 ± 0.7 cm, P = .009) pregnancies. Freedom from combined endpoints was significantly higher for patients in the pregnancy group than those in the nonpregnancy group (P = .002).

CONCLUSIONS

Pregnancy was not associated with significantly increased adverse events in patients following the Ross procedure. Special care should be taken after the first pregnancy, as multiparity may lead to increased neoaortic dilatation.

Impact of Preeclampsia on Clinical and Functional Outcomes in Women With Peripartum Cardiomyopathy

BACKGROUND

Preeclampsia is a risk factor for the development of peripartum cardiomyopathy (PPCM), but it is unknown whether preeclampsia impacts clinical or left ventricular (LV) functional outcomes. This study sought to assess clinical and functional outcomes in women with PPCM complicated by preeclampsia.

METHODS AND RESULTS

This retrospective cohort study included women diagnosed with PPCM delivering at Barnes-Jewish Hospital between 2004 to 2014. The primary outcome was one-year event-free survival rate for the combined end point of death and hospital readmission. The secondary outcome was recovery of LV ejection fraction. Seventeen of 39 women (44%) with PPCM had preeclampsia. The groups had similar mean LV ejection fraction at diagnosis (29.6 with versus 27.3 without preeclampsia; P=0.5). Women with preeclampsia had smaller mean LV end-diastolic diameters (5.2 versus 6.0 cm; P=0.001), greater relative wall thickness (0.41 versus 0.35 mm Hg; P=0.009), and lower incidence of eccentric remodeling (12% versus 48%; P=0.03). Clinical follow-up was available for 32 women; 5 died of cardiovascular complications within 1 year of diagnosis (4/15 with versus 1/17 without preeclampsia; P=0.16). In time to event analysis, patients with preeclampsia had worse event-free survival during 1-year follow-up (P=0.047). Echocardiographic follow-up was available in 10 survivors with and 16 without preeclampsia. LV ejection fraction recovered in 80% of survivors with versus 25% without preeclampsia (P=0.014).

CONCLUSIONS

PPCM with concomitant preeclampsia is associated with increased morbidity and mortality and different patterns of LV remodeling and recovery of LV function when compared with patients with PPCM that is not complicated by preeclampsia.

Sequential incremental doses of bisacodyl increase the diagnostic accuracy of colonic manometry

BACKGROUND

Colonic manometry is the standard diagnostic modality for evaluating colonic motility in children. Intraluminal bisacodyl is routinely used to trigger high-amplitude propagating contractions (HAPCs), a feature of normal colonic motility. Usually, only a single dose (0.2 mg/kg) is suggested. We retrospectively explored whether the use of an additional higher (0.4 mg/kg) dose of bisacodyl increases the yield of colonic manometry.

METHODS

In 103 children (median age: 8.8 years, range 3.2-15.7 years) with a diagnosis of slow transit constipation, colonic motility was recorded for 1 h before and 1 h after each of two incremental doses of bisacodyl (low, L, dose: 0.2 mg/kg, max 10 mg; high, H, dose: 0.4 mg/kg, max 20 mg) and the characteristics of HAPCs analyzed.

KEY RESULTS

High-amplitude propagating contractions were seen in 85 children. H dose significantly increased the proportion of patients with fully propagated HAPCs (H dose: 57/103 [55%], L dose: 27/103 [26%], p < 0.001), paralleling the significant decrease in the proportion with partially propagated HAPCs (H dose: 29/103 [28%], L dose: 47/103 [46%], p < 0.01). Mean HAPC number significantly increased throughout the colon at H compared to L dose (7.2 ± 5.05 vs 5.6 ± 5.1, p < 0.05). Finally, the proportion of patients with normal pressure wave morphology of HAPCs significantly increased with higher dose (H dose: 55/85 [65%], L dose: 27/85 [32%], p < 0.001).

CONCLUSIONS & INTERFERENCES

An additional higher dose of bisacodyl during colonic manometry improves colonic neuromuscular function suggesting its use might improve interpretation and decision making in children with slow transit constipation.

Acute Myocardial Infarction in Women: A Scientific Statement From the American Heart Association

Cardiovascular disease is the leading cause of mortality in American women. Since 1984, the annual cardiovascular disease mortality rate has remained greater for women than men; however, over the last decade, there have been marked reductions in cardiovascular disease mortality in women. The dramatic decline in mortality rates for women is attributed partly to an increase in awareness, a greater focus on women and cardiovascular disease risk, and the increased application of evidence-based treatments for established coronary heart disease. This is the first scientific statement from the American Heart Association on acute myocardial infarction in women. Sex-specific differences exist in the presentation, pathophysiological mechanisms, and outcomes in patients with acute myocardial infarction. This statement provides a comprehensive review of the current evidence of the clinical presentation, pathophysiology, treatment, and outcomes of women with acute myocardial infarction.

Efficacy of the neurokinin-1 receptor antagonist aprepitant in children with cyclical vomiting syndrome

BACKGROUND

Aprepitant (Emend, Merck Sharp & Dohme Ltd, Haarlem, the Netherlands), a neurokinin-1 receptor antagonist, prevents vomiting in a range of conditions. No data are available on its use in children with cyclical vomiting syndrome (CVS).

AIM

We investigated the efficacy of aprepitant as prophylactic treatment or acute intervention in CVS children refractory to conventional therapies.

METHODS

Forty-one children (median age: 8 years) fulfilling NASPGHAN criteria treated acutely (RegA) or prophylactically (RegP) with aprepitant were retrospectively reviewed. Primary outcome was the clinical response (decrease in frequency and intensity of CVS episodes). Secondary outcomes were: number of CVS episodes/year, number of hospital admissions/year, CVS episode duration, number of vomits/h, symptom-free interval length (days), and school attendance percentage. The follow-up period was 18-60 months.

RESULTS

Sixteen children received RegP and 25 RegA. One child on RegP stopped treatment due to severe migraine. At 12-months on intention-to-treat analysis, 13 children on RegP (81%) achieved either complete (3/16, 19%) or partial (10/16, 62%) clinical response. On RegA, 19 children (76%) had either complete (3/25, 12%) or partial (16/25, 64%) response (P = 0.8 vs. RegP). In both RegP and RegA, there was a significant decrease in CVS episodes/year, hospital admission number/year, CVS episode length, number of vomits/h, as well as an increase in symptom-free interval duration and school attendance percentage. Side effects were reported only in RegP (5/16, 31%) including hiccough (3/16, 19%), asthenia/fatigue (2/16, 12.5%), increased appetite (2/16, 12.5%), mild headache (1/16, 6%) and severe migraine (1/16, 6%).

CONCLUSION

Aprepitant appears effective for both acute and prophylactic management of paediatric cyclical vomiting syndrome refractory to conventional therapies.

Dilated intercellular space diameter as marker of reflux-related mucosal injury in children with chronic cough and gastro-oesophageal reflux disease

BACKGROUND

The diagnostic corroboration of the relationship between gastro-oesophageal reflux disease (GERD) and chronic cough remains challenging.

AIMS

To compare oesophageal mucosal intercellular space diameter (ISD) in children with GERD, children with gastro-oesophageal reflux (GER)-related cough (GrC) and a control group, and to explore the relationship between baseline impedance levels and dilated ISD in children with GER-related cough.

METHODS

Forty children with GERD, 15 children with GrC and 12 controls prospectively underwent oesophagogastroduodenoscopy (EGD) with oesophageal biopsies taken 2-3 cm above squamocolumnar junction. ISD were quantified using transmission electron microscopy. Impedance-pH monitoring with evaluation of baseline impedance in the most distal impedance channel was performed in both patient groups.

RESULTS

A significant difference in mean ISD values was found between GrC patients (0.9 ± 0.2 μm) and controls (0.5 ± 0.2 μm, P < 0.001), whereas there was no difference between GrC and GERD group (1 ± 0.3 μm, NS). No difference was found in the mean ISD between GrC children with or without pathological oesophageal acid exposure time (1 ± 0.3 vs. 0.9 ± 0.2 μm), and there was no correlation between ISD and any reflux parameter. Finally, there was no correlation between ISD and distal baseline impedance values (r:-0.35; NS).

CONCLUSIONS

In children with reflux-related cough, dilated intercellular space diameter appears to be an objective and useful marker of oesophageal mucosal injury regardless of acid exposure, and its evaluation should be considered for those patients where the diagnosis is uncertain. In children with reflux-related cough, baseline impedance levels have no role in identifying reflux-induced oesophageal mucosal ultrastructural changes.

High-resolution colonic manometry accurately predicts colonic neuromuscular pathological phenotype in pediatric slow transit constipation

BACKGROUND

Severe pediatric slow transit constipation (STC) is commonly due to intrinsic colonic neuromuscular disease. We sought to correlate neuromuscular histological phenotypes in pediatric STC with colonic manometric phenotypes using high-resolution manometry (HRM). We tested the hypothesis that failure of motor quiescence (FQ) between bisacodyl-induced high amplitude propagating sequences (HAPSs) might predict neuromuscular pathology.

METHODS

Eighteen children (10 males, median age: 7.5 years) with refractory STC underwent stationary colonic HRM before segmental colonic resection. Six age-matched constipated children with normal colonic transit served as controls. Colonic resection specimens underwent histopathological analysis. Conventional manometric parameters and area under the curve (AUC) during a 1-min period following bisacodyl-induced HAPSs [PBAUC(1) ], as measure of FQ, were calculated.

KEY RESULTS

Numbers of postbisacodyl HAPSs in descending and sigmoid segments were lower in patients than controls (P < 0.01, respectively). Low amplitude propagating sequences (LAPSs) were common prebisacodyl in controls and rare in STC (P < 0.001), whereas postbisacodyl LAPS were more common in STC (P < 0.001). Postbisacodyl, both retrograde propagating contractions and bursts of contractions were present in STC patients only (P < 0.001 and P < 0.01). Postbisacodyl simultaneous pressurization was seen only in STC (P < 0.05 and P < 0.001, in descending and rectosigmoid segments). Histological abnormalities were present in 17/18. Fourteen were neurogenic, one neuro-myogenic, and two myogenic. In segments with HAPS, PBAUC(1) was predictive of colonic neuropathy using a cutoff of 205 mmHg.s(-1) (Sensitivity 100%, specificity 86%, PPV92%, NPV100%).

CONCLUSIONS & INFERENCES

PBAUC(1) is increased in multiple colonic segments in neuropathic pediatric STC and constitutes a sensitive and specific biomarker of neuropathy.

High-resolution colonic manometry accurately predicts colonic neuromuscular pathological phenotype in pediatric slow transit constipation

BACKGROUND

Severe pediatric slow transit constipation (STC) is commonly due to intrinsic colonic neuromuscular disease. We sought to correlate neuromuscular histological phenotypes in pediatric STC with colonic manometric phenotypes using high-resolution manometry (HRM). We tested the hypothesis that failure of motor quiescence (FQ) between bisacodyl-induced high amplitude propagating sequences (HAPSs) might predict neuromuscular pathology.

METHODS

Eighteen children (10 males, median age: 7.5 years) with refractory STC underwent stationary colonic HRM before segmental colonic resection. Six age-matched constipated children with normal colonic transit served as controls. Colonic resection specimens underwent histopathological analysis. Conventional manometric parameters and area under the curve (AUC) during a 1-min period following bisacodyl-induced HAPSs [PBAUC(1) ], as measure of FQ, were calculated.

KEY RESULTS

Numbers of postbisacodyl HAPSs in descending and sigmoid segments were lower in patients than controls (P < 0.01, respectively). Low amplitude propagating sequences (LAPSs) were common prebisacodyl in controls and rare in STC (P < 0.001), whereas postbisacodyl LAPS were more common in STC (P < 0.001). Postbisacodyl, both retrograde propagating contractions and bursts of contractions were present in STC patients only (P < 0.001 and P < 0.01). Postbisacodyl simultaneous pressurization was seen only in STC (P < 0.05 and P < 0.001, in descending and rectosigmoid segments). Histological abnormalities were present in 17/18. Fourteen were neurogenic, one neuro-myogenic, and two myogenic. In segments with HAPS, PBAUC(1) was predictive of colonic neuropathy using a cutoff of 205 mmHg.s(-1) (Sensitivity 100%, specificity 86%, PPV92%, NPV100%).

CONCLUSIONS & INFERENCES

PBAUC(1) is increased in multiple colonic segments in neuropathic pediatric STC and constitutes a sensitive and specific biomarker of neuropathy.

Relationship between baseline impedance levels and esophageal mucosal integrity in children with erosive and non-erosive reflux disease

BACKGROUND

Baseline impedance measurement has been reported to be related to esophageal acid exposure and hypothesized to be a marker of microscopic changes of the esophageal mucosa. Aims of the study were to establish whether any relationship existed between the magnitude of intercellular space diameter (ISD) of esophageal mucosa and baseline impedance levels in children with gastro-esophageal reflux disease (GERD), and to compare baseline impedance levels between children with non erosive (NERD) and erosive (ERD) reflux disease.

METHODS

Fifteen children (median age: 11.2 years) with NERD, and 11 with ERD (median age: 9.6 years) were prospectively studied. All patients underwent upper endoscopy. Biopsies were taken 2-3cm above the Z-line, and ISD was measured using transmission electron microscopy. All patients underwent impedance pH-monitoring, and baseline impedance levels were assessed in the most distal impedance channel.

KEY RESULTS

Mean (±SD) ISD did not differ between NERD (1.0±0.3μm) and ERD (1.1 ± 0.3 μm, ns). Considering all patients together, no correlation was found between distal baseline impedance and ISD (r: -0.15; ns). Conversely, negative correlations were found between distal baseline impedance and acid exposure time (r: -0.76; P<0.001), long-lasting reflux episodes (r: -0.78; P<0.001), acid reflux episodes (r: -0.62; P<0.001), and acid clearance time (r: -0.79; P<0.001). Distal baseline impedance was significantly lower in ERD [1455 (947-2338) Ω] than in NERD children [3065 (2253-3771) Ω; P<0.01].

CONCLUSIONS & INFERENCES

  In children with GERD baseline impedance levels are not useful in predicting reflux-induced ultrastructural changes in the esophageal mucosa, despite their ability to discriminate between NERD and ERD.

Gastric emptying is accelerated following laparoscopic Nissen fundoplication

AIM OF THE STUDY

The effects on gastric motility following Nissen fundoplication in children are poorly documented. Some paediatric surgeons advocate additional procedures at the same time as fundoplication, such as a pyloroplasty, to enhance gastric emptying. The aim of this study was to determine whether laparoscopic Nissen fundoplication without pyloroplasty affects gastric emptying.

METHODS

Gastric emptying was measured before laparoscopic Nissen fundoplication in 8 children after ingestion of a standardised volume of milk for age mixed with 150 mg of (13)C-octanoic acid. None of the patients had a gastrostomy insertion at the time of fundoplication and 2 patients had neurological impairment. Breath samples were collected by breathing into a mask at baseline and every 15 minutes up to 3 hours, and were analysed for (13)CO (2)/ (12)CO (2) ratio by mass spectrometry. Gastric emptying time (t (1/2)) was derived from the curve of (13)CO (2)/ (12)CO (2) ratio against time. The test was repeated in 6 children following Nissen fundoplication at the time of full feeds. Data are reported as mean +/- SD and were analysed by the Mann-Whitney test.

RESULTS AND CONCLUSIONS

There were 4 males and 4 females; mean age at surgery was 3.3 +/- 3.0 years. Mean gastric emptying time was 59 +/- 17 min prior to laparoscopic Nissen fundoplication and 45 +/- 4 min following surgery (p = 0.03). Gastric emptying was accelerated in all except one patient. Gastric emptying for liquids is accelerated following Nissen fundoplication in children. Procedures aimed at improving gastric emptying time such as pyloroplasty or pyloromyotomy might not be justified at the time of laparoscopic Nissen fundoplication.

Gastrointestinal complications of epidermolysis bullosa in children

BACKGROUND

Epidermolysis bullosa (EB) is a group of inherited disorders characterized by skin and mucous membrane fragility. Gastrointestinal (GI) complications have been described in many types of EB and are responsible for significant morbidity.

OBJECTIVES

To delineate the nature and frequency of GI complications in a large cohort of paediatric patients with EB and to postulate why some complications occur more commonly in some specific subtypes.

METHODS

The case notes of 223 children with EB seen at a national referral centre were examined retrospectively for the presence of GI symptoms, investigations and interventions.

RESULTS

GI complications were present in 130/223 (58%) of all patients. In EB simplex, constipation and gastro-oesophageal reflux (GOR) were frequently observed. In junctional EB, failure to thrive and protein-losing enteropathy (PLE) were the prominent GI manifestations. Constipation was common in patients with dystrophic EB (DEB) requiring laxatives and in some cases fibre supplementation. GOR affected three-quarters of those with recessive DEB, two-thirds also having significant oesophageal strictures. Over half of patients with recessive DEB required gastrostomy insertion. Diarrhoea affected a small but significant proportion of children with recessive DEB with macroscopic and/or microscopic changes of colitis in the majority.

CONCLUSION

GI problems in EB are very common with subtype specificity for some of these complications. The occurrence of diarrhoea, PLE and colitis in the context of EB has not been highlighted previously, and may arise secondarily to antigenic exposure in the gut lumen as a result of mucosal fragility.

Topical application of mitomycin-C in oesophageal strictures

BACKGROUND

Benign oesophageal strictures may occur as a complication of caustic ingestion or severe gastro-oesophageal reflux or as a sequela of oesophageal surgery and other fibrosing conditions. The traditional initial treatment of oesophageal strictures is intraluminal dilation; however, even if frequent, this occasionally may not provide adequate oesophageal lumen capacity or give significant symptom-free intervals, and restricturing after dilation is difficult and challenging. Topical postdilation application of an antifibrotic agent, mitomycin-C, in the treatment of an oesophageal stricture has been described.

PATIENTS AND METHODS

Eight centres participated, with a total of 16 patients (4 girls), median age 48 (range 0-276) months. The causes of stricture were as follows: caustic (10), post-trachea-oesophageal fistula repair (2), peptic (2), Crohn disease (1), and dystrophic epidermolysis bullosa (1). The median (range) length and diameter of the strictures were as follows: 22 mm (8-50 mm) and 1.5 mm (1-6 mm). Of the 16 patients, 15 had undergone repeated dilations varying from 3 to more than 1000 (daily self-bouginage) before mitomycin-C, and the median interval between dilations was 4 weeks. Mitomycin-C 0.1 mg/mL was applied after dilation for a median time of 3.5 minutes and a median of 3 (1-12) times.

RESULTS

Major success, both endoscopic and clinical improvement or cure, occurred in 10 of 16 patients. In 3 of 16 patients the interval period between dilations increased dramatically. Failure of therapy was considered in 3 of 16. All of the patients remained symptom free for a follow-up time of as long as 5 years.

CONCLUSIONS

Postdilation application of topical mitomycin-C resulted in major success in 62.5% of patients and partial success in 19%, and it may be a useful strategy in oesophageal strictures of differing causes that are refractory to repeated perendoscopic dilation.

Systemic vasculitis: a cause of indeterminate intestinal inflammation

OBJECTIVES

Indeterminate intestinal inflammation may result from a variety of inflammatory conditions in addition to ulcerative colitis and Crohn disease. The primary systemic vasculitides may present with intestinal inflammation and an indeterminate colitis. We set out to describe a series of children with primary systemic vasculitis who initially presented with clinical features suggestive of inflammatory bowel disease (IBD) to establish criteria that might help discriminate between IBD and primary systemic vasculitis.

METHODS

Ten children (6 boys, median age at presentation 8.9 years, range 0.9-14.5 years) satisfied inclusion criteria.

RESULTS

All had abdominal pain, weight loss, diarrhea (6 of 10 bloody) and laboratory evidence of a severe acute phase response. Extraintestinal clinical features included vasculitic rash, renal impairment, myalgia, testicular pain and polyarthritis. Endoscopy showed vascular changes or other macroscopic findings suggestive of vasculitis in 5 of 10 patients. Gut histology revealed indeterminate chronic inflammatory mucosal changes and one patient with small artery fibrinoid necrosis in the submucosal vessels. Extraintestinal biopsy was performed in 6 patients and had a higher yield for the demonstration of vasculitis than intestinal biopsy. The results of selective visceral angiography was suggestive of vasculitis in all patients, but was normal in 7 cases of treatment-unresponsive classic IBD. Treatment comprised corticosteroid and azathioprine in all patients. Cyclophosphamide was given to 7 of 10 patients.

CONCLUSIONS

Extraintestinal manifestations and inflammatory responses that may be disproportionate to the degree of intestinal inflammation provide clues to the presence of an underlying primary systemic vasculitis, and these data suggest that selective visceral angiography plays a key role in the diagnosis of vasculitis in this context. It is important to identify and treat any vasculitic component because failure to do so may result in consequential morbidity or mortality.

Hyperinsulinemic hypoglycemia in Beckwith-Wiedemann syndrome due to defects in the function of pancreatic beta-cell adenosine triphosphate-sensitive potassium channels

BACKGROUND

Beckwith-Wiedemann syndrome (BWS) is a congenital overgrowth syndrome that is clinically and genetically heterogeneous. Hyperinsulinemic hypoglycemia occurs in about 50% of children with BWS and, in the majority of infants, it resolves spontaneously. However, in a small group of patients the hypoglycemia can be persistent and may require pancreatectomy. The mechanism of persistent hyperinsulinemic hypoglycemia in this group of patients is unclear.

PATIENTS AND METHODS

Using patch-clamp techniques on pancreatic tissue obtained at the time of surgery, we investigated the electrophysiological properties of ATP-sensitive K(+) (K(ATP)) channels in pancreatic beta-cells in a patient with BWS and severe medically-unresponsive hyperinsulinemic hypoglycemia.

RESULTS

Persistent hyperinsulinism was found to be caused by abnormalities in K(ATP) channels of the pancreatic beta-cell. Immunofluorescence studies using a SUR1 antibody revealed perinuclear pattern of staining in the BWS cells, suggesting a trafficking defect of the SUR1 protein. No mutations were found in the genes ABCC8 and KCNJ11 encoding for the two subunits, SUR1 and KIR6.2, respectively, of the K(ATP) channel. Genetic analysis of this patients BWS showed evidence of mosaic paternal isodisomy.

CONCLUSIONS

In this novel case of BWS with mosaic paternal uniparental disomy for 11p15, persistent hyperinsulinism was due to abnormalities in K(ATP) channels of the pancreatic beta-cell. The mechanism/s by which mosaic paternal uniparental disomy for 11p15 causes a trafficking defect in the SUR1 protein of the K(ATP) channel remains to be elucidated.