Identification of novel pathogenic copy number variations in Charcot-Marie-Tooth disease.

Charcot-Marie-Tooth disease (CMT) is a hereditary sensory-motor neuropathy characterized by a strong clinical and genetic heterogeneity. Over the past few years, with the occurrence of whole-exome sequencing (WES) or whole-genome sequencing (WGS), the molecular diagnosis rate has been improved by allowing the screening of more than 80 genes at one time. In CMT, except the recurrent PMP22 duplication accounting for about 60% of pathogenic variations, pathogenic copy number variations (CNVs) are rarely reported and only a few studies screening specifically CNVs have been performed. The aim of the present study was to screen for CNVs in the most prevalent genes associated with CMT in a cohort of 200 patients negative for the PMP22 duplication. CNVs were screened using the Exome Depth software on next generation sequencing (NGS) data obtained by targeted capture and sequencing of a panel of 81 CMT associated genes. Deleterious CNVs were identified in four patients (2%), in four genes: GDAP1, LRSAM1, GAN, and FGD4. All CNVs were confirmed by high-resolution oligonucleotide array Comparative Genomic Hybridization (aCGH) and/or quantitative PCR. By identifying four new CNVs in four different genes, we demonstrate that, although they are rare mutational events in CMT, CNVs might contribute significantly to mutational spectrum of Charcot-Marie-Tooth disease and should be searched in routine NGS diagnosis. This strategy increases the molecular diagnosis rate of patients with neuropathy.

Natural disease course and genotype-phenotype correlations in Complex I deficiency caused by nuclear gene defects: what we learned from 130 cases.

Mitochondrial complex I is the largest multi-protein enzyme complex of the oxidative phosphorylation system. Seven subunits of this complex are encoded by the mitochondrial and the remainder by the nuclear genome. We review the natural disease course and signs and symptoms of 130 patients (four new cases and 126 from literature) with mutations in nuclear genes encoding structural complex I proteins or those involved in its assembly. Complex I deficiency caused by a nuclear gene defect is usually a non-dysmorphic syndrome, characterized by severe multi-system organ involvement and a poor prognosis. Age at presentation may vary, but is generally within the first year of life. The most prevalent symptoms include hypotonia, nystagmus, respiratory abnormalities, pyramidal signs, dystonia, psychomotor retardation or regression, failure to thrive, and feeding problems. Characteristic symptoms include brainstem involvement, optic atrophy and Leigh syndrome on MRI, either or not in combination with internal organ involvement and lactic acidemia. Virtually all children ultimately develop Leigh syndrome or leukoencephalopathy. Twenty-five percent of the patients died before the age of six months, more than half before the age of two and 75 % before the age of ten years. Some patients showed recovery of certain skills or are still alive in their thirties . No clinical, biochemical, or genetic parameters indicating longer survival were found. No clear genotype-phenotype correlations were observed, however defects in some genes seem to be associated with a better or poorer prognosis, cardiomyopathy, Leigh syndrome or brainstem lesions.

COVID-19 in children at Strasbourg University Hospital: A retrospective study of the first 2months of the epidemic.

CONTEXT: The emergence and rapid spread of coronavirus disease 2019 (COVID-19) have shaken the planet, both in terms of health and economical aspects, constituting a real challenge for the scientific community. PROBLEM: At the time of the arrival of the epidemic in France, there were limited data regarding how COVID-19 could affect children. A lesser severity compared with adults was described, but knowledge concerning clinical forms and screening strategies was missing. METHODOLOGY: In this retrospective and non-interventional epidemiological study, we aimed to describe the epidemiology and the clinical features of COVID-19 pediatric disease in the first university hospital affected by the epidemic in France. We included all underage patients who tested positive for SARS-CoV-2 by polymerase chain reaction (PCR) assays on nasopharyngeal smears performed between February 25, 2020 and April 30, 2020. RESULTS: The presence of fever and respiratory signs was frequent (>50%), as was the presence of general or digestive signs, but patients were also frequently asymptomatic, making the discovery of a positive smear fortuitous. There were no deaths in our cohort. CONCLUSION: No patient with a serious form of COVID-19 was treated in the pediatrics departments of Strasbourg University Hospital during the first 2 months of the epidemic. Diagnostic strategies have evolved over the course of the epidemic, ranging from exploring relevant symptoms to systematic screening.

Diagnostic and severity scores for Cockayne syndrome.

BACKGROUND: Cockayne syndrome is a progressive multisystem genetic disorder linked to defective DNA repair and transcription. This rare condition encompasses a very wide spectrum of clinical severity levels ranging from severe prenatal onset to mild adult-onset subtypes. The rarity, complexity and variability of the disease make early diagnosis and severity assessment difficult. Based on similar approaches in other neurodegenerative disorders, we propose to validate diagnostic and severity scores for Cockayne syndrome. METHODS: Clinical, imaging and genetic data were retrospectively collected from 69 molecularly confirmed CS patients. A clinical diagnostic score and a clinical-radiological diagnostic score for CS were built using a multivariable logistic regression model with a stepwise variable selection procedure. A severity score for CS was designed on five items (head circumference, growth failure, neurosensorial signs, motor autonomy, communication skills) and validated by comparison with classical predefined severity subtypes of CS. RESULTS: Short stature, enophtalmos, hearing loss, cataracts, cutaneous photosensitivity, frequent dental caries, enamel hypoplasia, morphological abnormalities of the teeth, areflexia and spasticity were included in the clinical diagnostic score as being the most statistically relevant criteria. Appropriate weights and thresholds were assigned to obtain optimal sensitivity and specificity (95.7% and 86.4% respectively). The severity score was shown to be able to quantitatively differentiate classical predefined subtypes of CS and confirmed the continuous distribution of the clinical presentations in CS. Longitudinal follow-up of the severity score was able to reflect the natural course of the disease. CONCLUSION: The diagnostic and severity scores for CS will facilitate early diagnosis and longitudinal evaluation of future therapeutic interventions. Prospective studies will be needed to confirm these findings.

Mutation update for the CSB/ERCC6 and CSA/ERCC8 genes involved in Cockayne syndrome.

Cockayne syndrome is an autosomal recessive multisystem disorder characterized principally by neurological and sensory impairment, cachectic dwarfism, and photosensitivity. This rare disease is linked to mutations in the CSB/ERCC6 and CSA/ERCC8 genes encoding proteins involved in the transcription-coupled DNA repair pathway. The clinical spectrum of Cockayne syndrome encompasses a wide range of severity from severe prenatal forms to mild and late-onset presentations. We have reviewed the 45 published mutations in CSA and CSB to date and we report 43 new mutations in these genes together with the corresponding clinical data. Among the 84 reported kindreds, 52 (62%) have mutations in the CSB gene. Many types of mutations are scattered along the whole coding sequence of both genes, but clusters of missense mutations can be recognized and highlight the role of particular motifs in the proteins. Genotype-phenotype correlation hypotheses are considered with regard to these new molecular and clinical data. Additional cases of molecular prenatal diagnosis are reported and the strategy for prenatal testing is discussed. Two web-based locus-specific databases have been created to list all identified variants and to allow the inclusion of future reports (www.umd.be/CSA/ and www.umd.be/CSB/).

Epidemiological, clinical, paraclinical and molecular study of a cohort of 102 patients affected with autosomal recessive progressive cerebellar ataxia from Alsace, Eastern France: implications for clinical management.

While Friedreich's ataxia (FRDA) and ataxia telangiectasia (AT) are known to be the two most frequent forms of autosomal recessive cerebellar ataxia (ARCA), knowledge on the other forms of ARCA has been obtained only recently, and they appear to be rarer. Little is known about the epidemiological features and the relative frequency of the ARCAs and only few data are available about the comparative features of ARCAs. We prospectively studied 102 suspected ARCA cases from Eastern France (including 95 from the Alsace region) between 2002 and 2008. The diagnostic procedure was based on a sequential strategic scheme. We examined the clinical, paraclinical and molecular features of the large cohort of patients and compared features and epidemiology according to molecular diagnosis. A molecular diagnosis could be established for 57 patients; 36 were affected with FRDA, seven with ataxia plus oculomotor apraxia type 2 (AOA2), four with AT, three with ataxia plus oculomotor apraxia type 1 (AOA1), three with Marinesco-Sjögren syndrome, two with autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS), one with ataxia with vitamin E deficiency (AVED) and one with autosomal recessive cerebellar ataxia type 2 (ARCA2). The group of patients with no identified mutation had a significantly lower spinocerebellar degeneration functional score corrected for disease duration (SDFS/DD ratio; p = 0.002) and comprised a significantly higher proportion of cases with onset after 20 years (p < 0.01). Extensor plantar reflexes were rarer and cerebellar atrophy was more frequent in the group of patients with a known non-Friedreich ARCA compared to all other patients (p < 0.0001 and p = 0.0003, respectively). Lower limb areflexia and electroneuromyographic evidences of peripheral neuropathy were more frequent in the Friedreich ataxia group than in the group with a known non-Friedreich ataxia and were more frequent in the later group than in the group with no identified mutation (p = 0.0001 and p = 0.01, respectively). The overall prevalence of ARCA in Alsace is 1/19,000. We can infer the prevalence of FRDA in Alsace to be 1/50,000 and infer that AT is approximately eight times less frequent than FRDA. MSS, AOA2 and ARSACS appear only slightly less frequent than AT. Despite the broad variability of severity, Friedreich ataxia patients are clinically distinct from the other forms of ARCA. Patients with no identified mutation have more often a pure cerebellar degenerative disease or a spastic ataxia phenotype. It appears that ARCA cases can be divided into two major groups of different prognosis, an early-onset group with a highly probable genetic cause and an adult-onset group with better prognosis for which a genetic cause is more difficult to prove but not excluded. ARCAs are rare, early-disabling and genetically heterogeneous diseases dominated by FRDA. Several of the recently identified ARCAs, such as AVED, ARSACS, AOA1, AOA2 and MSS, have a prevalence close to AT and should be searched for extensively irrespective of ethnic origins. The strategic scheme is a useful tool for the diagnosis of ARCAs in clinical practice.

The Iberian legacy into a young genetic xeroderma pigmentosum cluster in central Brazil.

In central Brazil, in the municipality of Faina (state of Goiás), the small and isolated village of Araras comprises a genetic cluster of xeroderma pigmentosum (XP) patients. The high level of consanguinity and the geographical isolation gave rise to a high frequency of XP patients. Recently, two founder events were identified affecting that community, with two independent mutations at the POLH gene, c.764 + 1 G > A (intron 6) and c.907 C > T; p.Arg303* (exon 8). These deleterious mutations lead to the xeroderma pigmentosum variant syndrome (XP-V). Previous reports identified both mutations in other countries: the intron 6 mutation in six patients (four families) from Northern Spain (Basque Country and Cantabria) and the exon 8 mutation in two patients from different families in Europe, one of them from Kosovo. In order to investigate the ancestry of the XP patients and the age for these mutations at Araras, we generated genotyping information for 22 XP-V patients from Brazil (16), Spain (6) and Kosovo (1). The local genomic ancestry and the shared haplotype segments among the patients showed that the intron 6 mutation at Araras is associated with an Iberian genetic legacy. All patients from Goiás, homozygotes for intron 6 mutation, share with the Spanish patients identical-by-descent (IBD) genomic segments comprising the mutation. The entrance date for the Iberian haplotype at the village was calculated to be approximately 200 years old. This result is in agreement with the historical arrival of Iberian individuals at the Goiás state (BR). Patients from Goiás and the three families from Spain share 1.8 cM (family 14), 1.7 cM (family 15), and a more significant segment of 4.7 cM within family 13. On the other hand, the patients carrying the exon 8 mutation do not share any specific genetic segment, indicating an old genetic distance between them or even no common ancestry.

Recessive hereditary methaemoglobinaemia, type II: delineation of the clinical spectrum.

Type II recessive hereditary methaemoglobinaemia (RHM) is a rare disease due to generalized NADH-cytochrome b5 reductase (cytb5r) deficiency. It results in mild cyanosis and severe neurological impairment. The clinical features and long-term outcome are poorly documented, and there are no systematic reviews. We examined six cases of type II RHM, four of which were new, together with 45 previously published cases, in order to establish the range of phenotypic expression. The clinical picture was very similar in most cases, with severe encephalopathy, microcephaly, generalized dystonia, movement disorders and mild cyanosis. The neurological prognosis was poor; in particular, none of the patients walked or spoke. In addition, the possibility of an atypical and milder phenotype was considered. We concluded that children with unexplained severe encephalopathy associated with generalized dystonia should be examined for cyanosis and have a methaemoglobinaemia assay performed. The diagnosis can be confirmed by very low cytb5r activity in both red and white blood cells. Here we report three novel mutations in the NADH-cytochrome b5 reductase gene. Prenatal diagnosis of this extremely severe disease should be proposed to affected families.

Cerebro-oculo-facio-skeletal syndrome: three additional cases with CSB mutations, new diagnostic criteria and an approach to investigation.

BACKGROUND: The cerebro-oculo-facio-skeletal syndrome (COFS syndrome) is an autosomal recessive disorder which was initially described in a specific aboriginal population from Manitoba. In recent years, COFS syndrome has been linked in this original population to a defective DNA repair pathway and to a homozygous mutation in the major gene underlying Cockayne syndrome (CSB). However, most reports of suspected COFS syndrome outside this population have not been confirmed at the molecular level, leading to considerable heterogeneity within the syndrome and confusing overlaps between COFS syndrome and other eye and brain disorders. OBJECTIVE: To refine the delineation of the syndrome on genetically proven COFS cases. METHODS: We report the exhaustive clinical, cellular and molecular data of three unrelated COFS patients with mutations in the CSB gene. RESULTS: All three patients present the cardinal features of COFS syndrome including extreme microcephaly, congenital cataracts, facial dysmorphism and arthrogryposis. They also exhibit a predominantly postnatal growth failure, a severe psychomotor retardation, with axial hypotonia and peripheral hypertonia and neonatal feeding difficulties. Fibroblasts from the patients show the same DNA repair defect which can be complemented by transfection of the CSB wild-type cDNA. Five new mutations in the CSB gene have been identified in these patients. CONCLUSIONS: Our data indicate that COFS syndrome represents the most severe end of the Cockayne spectrum. New diagnostic criteria for COFS syndrome are proposed, based on our findings and on the few genetically proven COFS cases from the literature.

Lyme neuroborreliosis in children: Report of nine cases and a review of the literature.

Lyme neuroborreliosis is a bacterial infection caused by the dissemination and proliferation of a Borrelia species in the central nervous system. Neuroborreliosis occurs after transmission of the pathogen from an infected tick to a human host during a tick bite. We report nine cases of pediatric neuroborreliosis collected by the National Observatory of Pediatric Bacterial Meningitis in France between 2001 and 2012. The nine children, aged 4-13 years, were identified in northern and eastern France and had the following clinical features: meningeal irritation alone or with facial palsy, or isolated facial palsy. All cases showed anti-Borrelia antibodies in cerebrospinal fluid or serum, or with a positive Borrelia PCR in the CSF. The outcome was favorable in all cases after a 2- to 3-week course of third-generation cephalosporin. On the basis of these nine pediatric cases, this study provides an update on the epidemiology, pathophysiology, diagnostic strategy, and treatment of neuroborreliosis, with insight into the specific features of pediatric neuroborreliosis and the difficulties encountered in the diagnosis of this infection.

[The place of neuropathy in the early diagnosis of Cockayne syndrome: Report on two siblings]. / Place de la neuropathie dans le diagnostic précoce du syndrome de Cockayne : à propos de deux cas dans une fratrie.

Two siblings affected with Cockayne syndrome (CS) are described: this diagnosis was suggested by the finding of a demyelinating neuropathy on electromyography in both children and consistent clinical features. CS is a rare genetic disorder with severe prognosis and a highly varied phenotype, making early diagnosis difficult. Taking into account these two cases and the literature, the current diagnosis criteria are insufficiently specific and appear late: the diagnosis may be delayed because multi-organ involvement and sensorial impairment suggests more frequent neurometabolic disorders. Neuroradiologic abnormalities are suggestive but may occur later. The finding of a demyelinating peripheral neuropathy seems to be a more useful marker to suspect this disorder in the presence of other clinical features. Further studies are required to better define the chronology of the symptoms, not only for adequate genetic counseling and eventual prenatal diagnosis, but also to assess the efficacy of future therapies.

[Severe acute pancreatitis in children receiving asparaginase: multicenter retrospective study]. / Pancréatites aiguës sévères à l'asparaginase chez l'enfant: étude rétrospective multicentrique.

UNLABELLED: Asparaginase is frequently used in the treatment of lymphoblastic malignancies in children and is a major cause of drug-induced acute pancreatitis. Severe cases of iatrogenic pancreatitis are uncommon but potentially lethal, and represent a diagnostic and therapeutic challenge. PATIENTS AND METHOD: We have retrospectively collected pediatric cases of severe acute pancreatitis induced by asparaginase, having occurred since January 1996 in participating centers from France and Belgium. RESULTS: Eleven patients, between four and 15 years old, have been included. Pancreatitis has been observed in all treatment phases, after 6 to 21 doses of asparaginase, 2 to 16 days after the last injection. Circulatory collapse (5/11), insulin-dependent diabetes (6/11) and pancreatic pseudokysts (7/11) were the major complications. Non-surgical treatment mainly included digestive rest, broad-spectrum antibiotic therapy and prolonged use of morphine. Asparaginase has been eventually reintroduced in three cases, and has caused a recurrence of pancreatitis in two of them. CONCLUSION: Intensive supportive management should enable a favourable outcome in most cases of acute pancreatitis induced by asparaginase in children. There is no way to predict the occurrence of this adverse event. Re-use of asparaginase should probably be ruled out.

[Diagnosis and natural history of Duchenne muscular dystrophy]. / Diagnostic et histoire naturelle de la dystrophie musculaire de Duchenne.

Duchenne myopathy is today the most frequently encountered progressive muscular dystrophy in children, with an inexorable, progressive development to death in the third decade. Improvement in survival is related to improvement in orthopaedic management, early screening of cardiac and respiratory complications, but no curative therapy can be applied today beyond recent pharmacogenetic advances. This diagnosis is raised with evidence of proximal muscular deficit beginning after an interval free of symptoms lasting from 1 to several years. Muscular dystrophy's mechanism is suggested by a significant increase in CK (creatine kinase) and confirmed by muscle biopsy. The clinical motor and cognitive heterogeneity of this disease and its natural history need to be well known because it conditions future therapeutic trials. Identification of outcome measures such as the 6-minute walk test, the MFM score, manual muscle testing musculaire, or biomarkers is indispensable for patient follow-up and collaborative studies.

Normal statural growth in 2 infants on chronic peritoneal dialysis: anecdotal or whole management-related.

AIMS: Growth retardation is usual in children on chronic peritoneal dialysis (CPD). Despite attention to many contributing factors (nutrition, dialysis dose, hemoglobin level, adynamic bone disease, hyperparathyroidism or rickets, growth hormone resistance, etc.), normal growth is rarely obtained in infants on CPD. MATERIALS AND METHODS: We had the chance to observe normal growth over a 1 year period in 2 consecutively treated infants on CPD. Louise (renal hypodysplasia) required CPD at the age of 1 month: creatinine 430 micromol/l; oliguric, creatinine clearance lower than 5 ml/min/1.73 m2. Nutrition was achieved orally with human milk during the first 6 months of life. Tidal peritoneal dialysis allowed a high dialysis dose Kt/V urea 3.8/week and Kcreatinine 105 l/week/1.73 m2. Hemoglobin was maintained over 13 g/dl and low levels of vitamin D analogue were prescribed to avoid adynamic bone disease. At the age of 1 year her height was 75 cm. i.e. in the normal range for age. Madeline (renal hypodysplasia) commenced on CPD at the age of 6 weeks and managed similarly. Her height at 1 year of age was 74 cm. RESULTS: In our 20 years of experience with children on dialysis, these 2 cases of normal statural growth for age at 1 year warrant discussion. As well as nutritional support, the new and recent therapeutic options in our team were: firstly, to avoid high doses of activated vitamin D to control PTH, as high doses are able to induce both a risk of adynamic bone disease and a direct bone cartilage toxicity: secondly, to maintain normal hemoglobin level; and thirdly, to deliver a high dialysis dose (urea, creatinine clearance) based on an individually adapted prescription. CONCLUSION: We feel this management approach is necessary to achieve optimal statural growth in children on chronic peritoneal dialysis. But this management concept only based on clinical anecdotal observations needs further evaluation before its use in clinical guidelines.

[Accidental ingestion of button battery]. / L'ingestion accidentelle de pile-bouton.

Button batteries are easily swallowed by children and may produce severe digestive injuries through two different mechanisms: electrochemical burns when in contact with the digestive mucosa, release of caustic substances when fragmented. Esophageal lesions are especially dangerous, as they can lead to perforation, fistula or secondary stenosis. The risk of mercury intoxication is less worrying since the assimilated fraction of the metal is unlikely to produce clinical effect. Although the large majority of the reported cases of button battery ingestion remained asymptomatic, the potentially lethal outcome justifies a precise diagnostic procedure: any button battery ingestion must be documented with a radiography of the digestive tract. Any battery lodged in the esophagus must be urgently removed by endoscopy. Other locations do not need any removal attempt unless complications: nonetheless a follow-up is necessary to confirm the spontaneous elimination of the battery. Manufacturers, physicians and parents share responsibility for preventing such accidents.

[Tetralogy of Fallot in monozygotic twins]. / Tétralogie de Fallot chez un couple de jumeaux monozygotes.

UNLABELLED: The causative mechanisms of congenital heart defects remain unclear and little is known about the respective implication of chance, genetics and environment, though recent findings in molecular biology may provide further insight into understanding the pathophysiologic basis of congenital heart diseases. CASE REPORT: We report the exceptional but significant case of monozygotic twins both affected by tetralogy of Fallot, for whom prenatal diagnosis ruled out 22q11 microdeletion. CONCLUSION: We discuss how far this observation is consistent with the latest hypothesis, which emphasizes the leading role of genetic factors. Several genes indeed, either separately or in combination, could be responsible for those defects, even if other influences may still come into play.

[Pemphigoid gestationis and bullous lesions in the newborn]. / Pemphigoïde gravidique et lésions bulleuses chez le nouveau-né.

BACKGROUND: Pemphigoid gestations is very seldom responsible for cutaneous lesions in newborns through passive transfer of the autoimmune disease from mother to infant. CASE REPORT: We report an additional case of a newborn presenting with an extensive but transitory bullous eruption despite the absence of circulating autoantibodies. CONCLUSION: Such examples of transplacental pemphigoid are so uncommon that the pathogenic role of IgG autoantibodies is being questioned.

Neuroimaging in Cockayne syndrome.

CS is an autosomal recessive multisystem disorder, which is mainly characterized by neurologic and sensory impairment, cachectic dwarfism, and photosensitivity. We describe the neuroimaging features (MR imaging, ¹H-MR spectroscopy, and CT) in the various clinical subtypes of CS from a cohort of genetically and biochemically proved cases. Hypomyelination, calcifications, and brain atrophy were the main imaging features. Calcifications were typically found in the putamen and less often in the cortex and dentate nuclei. Severe progressive atrophy was seen in the supratentorial white matter, the cerebellum, the corpus callosum, and the brain stem. Patients with early-onset disease displayed more severe hypomyelination and prominent calcifications in the sulcal depth of the cerebral cortex, but atrophy was less severe in late-onset patients. On proton MR spectroscopy, lactate was detected and Cho and NAA values were decreased. These combined neuroradiologic findings can help in the differential diagnosis of CS, distinguishing it from other leukoencephalopathies and/or cerebral calcifications in childhood.

Wide clinical variability among 13 new Cockayne syndrome cases confirmed by biochemical assays.

Cockayne syndrome is a multi-systemic, autosomal recessive disease characterised by postnatal growth failure and progressive multi-organ dysfunction. The main clinical features are severe dwarfism (<-2 SD), microcephaly (<-3 SD), psychomotor delay, sensorial loss (cataracts, pigmentary retinopathy, and deafness), and cutaneous photosensitivity. Here, 13 new cases of Cockayne syndrome are reported, which have been clinically diagnosed and confirmed using a biochemical transcription assay. The wide clinical variability, ranging from prenatal features to normal psychomotor development, is emphasised. When cardinal features are lacking, the diagnosis of Cockayne syndrome should be considered when presented with growth retardation, microcephaly, and one of the suggesting features such as enophthalmia, limb ataxia, abnormal auditory evoked responses, or increased ventricular size on cerebral imaging.