Valerie Meersschaut

Genetic screening of LCA in Belgium: predominance of CEP290 and identification of potential modifier alleles in AHI1 of CEP290‐related phenotypes

Leber Congenital Amaurosis (LCA), the most severe inherited retinal dystrophy, is genetically heterogeneous, with 14 genes accounting for 70% of patients. Here, 91 LCA probands underwent LCA chip analysis and subsequent sequencing of 6 genes (CEP290, CRB1, RPE65, GUCY2D, AIPL1and CRX), revealing mutations in 69% of the cohort, with major involvement of CEP290 (30%). In addition, 11 patients with early‐onset retinal dystrophy (EORD) and 13 patients with Senior‐Loken syndrome (SLS), LCA‐Joubert syndrome (LCA‐JS) or cerebello‐oculo‐renal syndrome (CORS) were included. Exhaustive re‐inspection of the overall phenotypes in our LCA cohort revealed novel insights mainly regarding the CEP290‐related phenotype. The AHI1 gene was screened as a candidate modifier gene in three patients with the same CEP290 genotype but different neurological involvement. Interestingly, a heterozygous novel AHI1 mutation, p.Asn811Lys, was found in the most severely affected patient. Moreover, AHI1 screening in five other patients with CEP290‐related disease and neurological involvement revealed a second novel missense variant, p.His758Pro, in one LCA patient with mild mental retardation and autism. These two AHI1 mutations might thus represent neurological modifiers of CEP290‐related disease.

Value of MR cholangiography in the evaluation of postoperative biliary complications following orthotopic liver transplantation

Abstract. The aim of this study was to describe the spectrum of abnormal biliary findings as seen with magnetic resonance cholangiography (MRC) in symptomatic patients after orthotopic liver transplantation (OLT). In our study we included 12 consecutive patients post-OLT who presented with clinical and/or biochemical suspicion of biliary complications. In all patients MRC was performed on a 1.0-T whole-body magnet and breathhold half-Fourier acquired single-shot turbo spin echo and rapid acquisition with relaxation enhancement sequences were used. Diagnostic confirmation was obtained with percutaneous transhepatic cholangiography (PTC; n = 3 patients), endoscopic retrograde cholangiography (ERC; n = 3 patients), or clinical follow-up. A vast array of biliary abnormalities were detected in 11 of 12 patients: high-grade, obstructive, anastomotic stricture was the most common unique abnormality. Findings consistent with bile duct necrosis, the second most common abnormality, were accompanied by arterial abnormalities in 2 of 5 patients on subsequent MR- and digital subtraction angiography. Compared with the findings obtained with direct cholangiography (n = 5 patients), MRC was highly accurate for the detection and characterization of postoperative biliary complications. Compared with the final diagnosis, which was based on PTC-ERC findings and/or all available clinical data, MRC imaging alone was able to provide a specific diagnosis in 9 of 12 patients. Magnetic resonance cholangiography is an accurate, time-saving, and non-invasive imaging modality in the evaluation of post-OLT patients in whom suspicion of biliary complications exists. Although the precise value of MRA in this patient group requires larger dedicated studies, single session “all-in-one” MR evaluation of both biliary and arterial system in our series proved to be a substantial benefit in obtaining an accurate and complete diagnosis.

Neonatal pulmonary interstitial glycogen accumulation disorder

An additional clinicohistopathological observation of neonatal pulmonary interstitial glycogenosis is described, confirming the findings in the original description by Canakis and coworkers [1]. The most striking finding is the presence of glycogen-laden cells within the interstitium of the lung. The outcome is favourable relative to other chronic interstitial lung diseases. We propose an alternative term as ‘‘glycogenosis’’ refers to a group of inborn errors of metabolism that are not related to this disease. A few hours after birth, a term infant developed signs of respiratory distress and was transferred with supplemental oxygen. Congenital heart disease was ruled out. In the hours after admission, the respiratory condition deteriorated and the baby was intubated and treated with surfactant, high frequency oscillation and nitric oxide inhalation for 12 days. Tracheal aspirate showed normal surfactant protein C and B. Chest X-ray films showed progressive hyperinflation and evolution to a mixed interstitial and alveolar pattern. Owing to chronic oxygen dependency and obvious tachypnoea, a high resolution CT scan of the chest was performed on day 55 demonstrating distortion of the lung architecture with the presence of linear opacities, mixed with areas of overinflation/emphysema and ground glass opacity. In the further work-up, cystic fibrosis was excluded and serum alpha-1-antitrypsin was normal. An infectious cause including Chlamydia, adenovirus, coxsackievirus, influenza, parainfluenza, Epstein-Barr virus, cytomegalovirus and Mycoplasma could not be demonstrated. Bacterial cultures remained sterile. A Mantoux test was negative. On day 68, an open lung biopsy was performed. Haematoxylin and eosin stained sections revealed diffuse thickening of the alveolar septae (Fig. 1A,B), while frozen sections showed the presence of abundant glycogen in the cytoplasm of the interstitial cells (Fig. 1C,D). Ultrastructural analysis of lead-contrasted ultrathin sections showed interstitial cells containing intracytoplasmic pools of high contrast granular material compatible with monoparticulate glycogen. Methylprednisolone pulse therapy was initiated at 10 mg/kg per day once daily for 3 days every month. There was no effect on oxygen need after 4 monthly treatments. The child was discharged home on supplemental oxygen at the age of 6 months and steroid therapy was continued monthly. Oxygen requirement decreased gradually and could be stopped at the age of 10 months, as was steroid therapy. He remained well except for a brief hospitalisation at the age of 1 year for a viral respiratory infection and 10 days hospitalisation at the age of 19 months because of bronchiolitis due to respiratory syncytial virus. Canakis and coworkers described seven cases of chronic interstitial lung disease (ILD) presenting with an atypical respiratory disorder during the neonatal period [1]. Most patients were symptomatic within 24 h after birth. Infectious or inflammatory causes of respiratory insufficiency were ruled out. All patients showed uniform histological features: thickened interstitium with immature interstitial cells containing abundant cytoplasmic glycogen. Although cytoplasm of occasional type 2 cells may contain residual aggregates of K. Smets (&) AE P. Vanhaesebrouck Neonatal Intensive Care Unit 1 B1, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium E-mail: koenraad.smets@ugent.be Tel.: +32-9-2403535 Fax: +32-9-2406105

Network injury to pulvinar with neonatal arterial ischemic stroke.

The purpose of this study is to establish that newborn stroke involving extensive parts of cerebral cortex immediately leads to secondary network injury in pulvinar. Seven term infants with cortical stroke presented with hypersignal in pulvinar on DWI. Stroke types included: complete MCA stroke (n=4); PCA stroke, ICA stroke and multiple artery stroke (1 each). Age range at scanning was between day 2 and 6 after birth (except for 1 infant scanned within 7 days of acute presentation during ECMO). ADC values in secondarily injured pulvinar were significantly higher than in the area with primary (sub)cortical injury (all patients scanned with identical MR image acquisition). In the absence of asphyxia and because pulvinar is outside of the primary area of infarction, we conclude that there are suggestions from imaging for acute secondary injury to pulvinar following primary damage of their cortical targets and/or connecting axons. Acute secondary injury is probably due to excitotoxicity and deafferentiation. The relevance of network injury for prognosis and the impact of early treatment on it have yet to be studied, in stroke but also in other acute perinatal brain disorders.

Mitochondrial mosaics in the liver of 3 infants with mtDNA defects

BackgroundIn muscle cytochrome oxidase (COX) negative fibers (mitochondrial mosaics) have often been visualized.MethodsCOX activity staining of liver for light and electron microscopy, muscle stains, blue native gel electrophoresis and activity assays of respiratory chain proteins, their immunolocalisation, mitochondrial and nuclear DNA analysis.ResultsThree unrelated infants showed a mitochondrial mosaic in the liver after staining for COX activity, i.e. hepatocytes with strongly reactive mitochondria were found adjacent to cells with many negative, or barely reactive, mitochondria. Deficiency was most severe in the patient diagnosed with Pearson syndrome. Ragged-red fibers were absent in muscle biopsies of all patients. Enzyme biochemistry was not diagnostic in muscle, fibroblasts and lymphocytes. Blue native gel electrophoresis of liver tissue, but not of muscle, demonstrated a decreased activity of complex IV; in both muscle and liver subcomplexes of complex V were seen. Immunocytochemistry of complex IV confirmed the mosaic pattern in two livers, but not in fibroblasts. MRI of the brain revealed severe white matter cavitation in the Pearson case, but only slight cortical atrophy in the Alpers-Huttenlocher patient, and a normal image in the 3rd. MtDNA in leucocytes showed a common deletion in 50% of the mtDNA molecules of the Pearson patient. In the patient diagnosed with Alpers-Huttenlocher syndrome, mtDNA was depleted for 60% in muscle. In the 3rd patient muscular and hepatic mtDNA was depleted for more than 70%. Mutations in the nuclear encoded gene of POLG were subsequently found in both the 2nd and 3rd patients.ConclusionHistoenzymatic COX staining of a liver biopsy is fast and yields crucial data about the pathogenesis; it indicates whether mtDNA should be assayed. Each time a mitochondrial disorder is suspected and muscle data are non-diagnostic, a liver biopsy should be recommended. Mosaics are probably more frequent than observed until now. A novel pathogenic mutation in POLG is reported.Tentative explanations for the mitochondrial mosaics are, in one patient, unequal partition of mutated mitochondria during mitoses, and in two others, an interaction between products of several genes required for mtDNA maintenance.

Colonic arteriovenous malformation in a child misinterpreted as an idiopathic colonic varicosis on angiography: remarks on current classification of childhood intestinal vascular malformations

A case of lower gastrointestinal hemorrhage in a child caused by an arteriovenous malformation (AVM) of the colon is presented. On diagnostic angiography, the lesion was misinterpretated as an idiopathic colonic varicosis because none of the characteristic features of an AVM were present. The role of angiography and shortcomings in nomenclature and classification of intestinal vascular anomalies in childhood are discussed.

Temps du transit colique chez l’enfant atteint de dysraphisme ouvert

INTRODUCTION Patients with open spinal dysraphism (OSD) frequently present constipation and incontinence requiring treatment. AIM Evaluation of colon transit time (CTT) in patients with OSD, in relation to neural lesion, mobility, bowel habits, and continence status. METHODS OSD patients aged between 6 and 20 years, who did not use antegrade enemas, were invited to participate in the study. Data from the medical file and information retrieved by questionnaires for constipation and incontinence were collected. The control group consisted of 13 healthy age-matched children. CTT was measured using the 6-day pellet method with an abdominal X-ray on day 7. Laxatives were continued and retrograde colon enemas were stopped 48h prior the X-ray. RESULTS Thirty of the 33 patients who met the inclusion criteria agreed to participate. Twelve (40%) patients were constipated (Rome III criteria) despite treatment. Fifteen (50%) were continent, with or without treatment. Total CTT was significantly longer in OSD patients (median CTT: 86.4h vs. 43.2h controls). Constipated OSD patients had a significantly prolonged CTT compared to non-constipated patients (CTT: 125.4h vs. 51.6h). Spontaneous continent OSD patients had a normal CTT (CTT: 33.6h). An abnormal CTT predicted the necessity of treatment to achieve continence (P<0.006). CONCLUSION CTT in OSD patients is significantly prolonged, indicating a neurogenic involvement of the bowel and a slow transit constipation. An abnormal CTT predicts the necessity of therapy to achieve fecal continence.

Mémoire originalTemps du transit colique chez l’enfant atteint de dysraphisme ouvertColon transit time in children and young adults with open spinal dysraphism

INTRODUCTION Patients with open spinal dysraphism (OSD) frequently present constipation and incontinence requiring treatment. AIM Evaluation of colon transit time (CTT) in patients with OSD, in relation to neural lesion, mobility, bowel habits, and continence status. METHODS OSD patients aged between 6 and 20 years, who did not use antegrade enemas, were invited to participate in the study. Data from the medical file and information retrieved by questionnaires for constipation and incontinence were collected. The control group consisted of 13 healthy age-matched children. CTT was measured using the 6-day pellet method with an abdominal X-ray on day 7. Laxatives were continued and retrograde colon enemas were stopped 48h prior the X-ray. RESULTS Thirty of the 33 patients who met the inclusion criteria agreed to participate. Twelve (40%) patients were constipated (Rome III criteria) despite treatment. Fifteen (50%) were continent, with or without treatment. Total CTT was significantly longer in OSD patients (median CTT: 86.4h vs. 43.2h controls). Constipated OSD patients had a significantly prolonged CTT compared to non-constipated patients (CTT: 125.4h vs. 51.6h). Spontaneous continent OSD patients had a normal CTT (CTT: 33.6h). An abnormal CTT predicted the necessity of treatment to achieve continence (P<0.006). CONCLUSION CTT in OSD patients is significantly prolonged, indicating a neurogenic involvement of the bowel and a slow transit constipation. An abnormal CTT predicts the necessity of therapy to achieve fecal continence.

Congenital bilateral plexiform neurofibromas of the cavernous sinuses

We report the CT and MRI findings of congenital bilateral plexiform neurofibromas of the cavernous sinuses in a 2-month-old girl. Contrast-enhanced CT showed enhancement of masses in both cavernous sinuses and enlargement of both superior orbital fissures. On MRI the masses were isointense with muscle on T1-weighted images, hypointense on T2-weighted images and showed strong homogeneous enhancement on contrast-enhanced T1-weighted images. A dural tail sign was observed. The diagnosis was proven by biopsy.

Acute Pancreatitis Complicated with Choledochal Duct Rupture

Recurrent acute pancreatitis is a rare clinical entity in childhood with unknown incidence (Rosendahl et al., 2007) and often occurring in a familial context. Genetic factors such as PRSS1 mutations (cationic trypsinogen gene) can be found in some patients. However, many remain idiopathic. The natural history remains poorly documented and the most frequent complications reported are pain, exocrine pancreatic insufficiency, diabetes mellitus, and pancreatic adenocarcinoma after long-standing hereditary pancreatitis. We describe a patient with hereditary pancreatitis in whom a mild pancreatitis episode was complicated by a perforation of the ductus choledochus.