A new highly penetrant form of obesity due to deletions on chromosome 16p11.2.

Obesity has become a major worldwide challenge to public health, owing to an interaction between the Western 'obesogenic' environment and a strong genetic contribution. Recent extensive genome-wide association studies (GWASs) have identified numerous single nucleotide polymorphisms associated with obesity, but these loci together account for only a small fraction of the known heritable component. Thus, the 'common disease, common variant' hypothesis is increasingly coming under challenge. Here we report a highly penetrant form of obesity, initially observed in 31 subjects who were heterozygous for deletions of at least 593 kilobases at 16p11.2 and whose ascertainment included cognitive deficits. Nineteen similar deletions were identified from GWAS data in 16,053 individuals from eight European cohorts. These deletions were absent from healthy non-obese controls and accounted for 0.7% of our morbid obesity cases (body mass index (BMI) >or= 40 kg m(-2) or BMI standard deviation score >or= 4; P = 6.4 x 10(-8), odds ratio 43.0), demonstrating the potential importance in common disease of rare variants with strong effects. This highlights a promising strategy for identifying missing heritability in obesity and other complex traits: cohorts with extreme phenotypes are likely to be enriched for rare variants, thereby improving power for their discovery. Subsequent analysis of the loci so identified may well reveal additional rare variants that further contribute to the missing heritability, as recently reported for SIM1 (ref. 3). The most productive approach may therefore be to combine the 'power of the extreme' in small, well-phenotyped cohorts, with targeted follow-up in case-control and population cohorts.

[Muscle biopsy in children: Usefulness in 2012]. / Intérêt de la biopsie musculaire chez l'enfant en 2012.

Muscle biopsy is a mainstay diagnostic tool for investigating neuromuscular disorders in children. We report the yield of pediatric muscle biopsy in a population of 415 children by a retrospective study of 419 biopsies performed between 1/01/2000 and 31/12/2009 in a neuropediatric department, including mitochondrial respiratory chain analysis for 87 children. Two hundred and fifty-five biopsies were from boys (61%) 164 from girls (39%). Their mean age at biopsy was 6.5years; 155 (37%) biopsies were obtained before the child was 5years old. Final histopathological diagnoses were: congenital myopathy (n=193, including 15 structural congenital myopathies); progressive muscular dystrophy (n=75 [18%] including 57 dystrophinopathies); congenital muscular dystrophy (n=17, including six primary merosinopathies); dermatomyositis (n=11); spinal muscular atrophy (n=9, including six atypical spinal muscular atrophies); metabolic myopathy (n=32, including 19 mitochondrial myopathies); encephalomyopathy (n=53 [13%], including 27 with a mitochondrial respiratory chain defect). Pathological diagnosis remained undetermined in 16 cases. In 184 patients (44%), the muscle biopsy revealed specific histopathological anomalies (dystrophic process; specific ultrastructural abnormalities; perifascicular atrophy; neurogenic atrophy; metabolic anomalies) enabling a precise etiological diagnosis. For 85% of progressive muscular dystrophies, the biopsy resulted in a genetic diagnosis after identification of the protein defect. In 15% of the congenital myopathies, histopathological anomalies focused attention on one or several genes. Concerning dystrophinopathies, quantification of dystrophin deficiency on the biopsy specimen contributed to the definition of the clinical phenotype: Duchenne, or Becker. In children with a myopathy, muscle biopsy is often indispensable to establish the etiological diagnosis. Based on the results from this series, muscle biopsy can provide a precise orientation in 45% of patients, leading to a genetic hypothesis.

[Phenotypic heterogeneity and phenotype-genotype correlations in dystrophinopathies: Contribution of genetic and clinical databases]. / Variabilité phénotypique et corrélations génotype-phénotype des dystrophinopathies : contribution des banques de données.

The objective of this work was to study the natural history of dystrophinopathies and the genotype-phenotype correlations made possible by the development of the clinical part of the French DMD database. The collection of 70,000 clinical data for 600 patients with an average longitudinal follow-up of 12years enabled clarification of the natural history of Duchenne and Becker muscular dystrophies and clinical presentations in symptomatic females. We were able to specify the phenotypic heterogeneity of motor, orthopedic and respiratory involvements (severe, standard and intermediary form), of the cardiac disorder (severe, standard or absent cardiomyopathy, absence of correlation between motor and cardiac involvements), and of brain function (mental deficiency in the patients with Becker muscular dystrophy, psychopathological disorders in dystrophinopathies). Phenotypic variability did not correlate with a specific mutational spectrum. We propose a model of phenotypic analysis based on the presence or not of muscular and cardiac involvements (described by age at onset and rate of progression) and brain involvement (described by the type and the severity of the cognitive impairment and of the psychological disorders). The methodology developed for the DMD gene can be generalized and used for other databases dedicated to genetic diseases. Application of this model of phenotypic analysis for each patient and further development of the database should contribute substantially to clinical research providing useful tools for future clinical trials.

Recommendations for the diagnosis and management of typical childhood spinal muscular atrophy.

Typical childhood spinal muscular atrophy is a disease that affects the anterior horn of the spinal cord related to SMN1 gene defects. Since no etiological treatment is currently available, its management is necessarily symptomatic and involves multidisciplinary care. The national plan on rare diseases for 2005-2008 developed by the French Ministry of Health resulted in the creation of 12 reference centres for neuromuscular diseases, mainly to improve their diagnosis and management. During the first one-day clinical research meeting on neuromuscular disorders, organized by the French Association to fight myopathies (AFM) in May 2007, clinicians from the 12 national reference centers led workshops for each of the main neuromuscular diseases. Concerning spinal muscular atrophy, discussions involving specialists from medical and allied professions were led by clinicians in charge of the workshop sessions. This paper reports the final version of their recommendation regarding the diagnosis, monitoring and management of typical infantile spinal muscular atrophy, which is necessarily multidisciplinary, including orthopedic, pulmonary, gastroenterology and nutrition care.

Delineation of 15q13.3 microdeletions.

The increasing use of array-comparative genomic hybridization (array-CGH) to identify copy number variations (CNVs) in patients with developmental delay (DD), mental retardation and/or dysmorphic features has allowed the recent recognition of numerous genomic imbalances, including the 15q13.3 microdeletion. Patients with this microdeletion generally present with relatively consistent breakpoints at BP4 and BP5, which include the CHRNA7 gene. About 100 index cases have been reported since the first publication in 2008. This large number of patients ascertained through highly variable samples has been necessary to describe the full phenotypic spectrum of this microdeletion, ranging from mental retardation with dysmorphic features, epilepsy, neuropsychiatric disturbances with or without cognitive impairment to complete absence of anomalies. Here, we describe a collaborative study reporting a new cohort of 12 index patients and 13 relatives carrying a heterozygous BP4-BP5 microdeletion out of a series of 4625 patients screened by array-CGH for DD. We confirm the clinical expressivity of the disease as well as the incomplete penetrance in seven families. We showed through a review of the literature that males are more likely to be symptomatic. Sequence analysis of CHRNA7 yielded no data to support the unmasking of recessive variants as a cause of phenotypic variability. We also report the first patient carrying a 15q13.3 homozygous microdeletion inherited from both parents. He had severe epileptic encephalopathy with retinopathy, autistic features and choreoathetosis. Besides the classical approximately 1.5 Mb BP4-BP5 microdeletion, we also describe three index patients and two relatives with a smaller 500 kb microdeletion, including the CHRNA7 gene.

Clinical and mutational spectrum of limb-girdle muscular dystrophy type 2I in 11 French patients.

BACKGROUND: Limb-girdle muscular dystrophy 2I (LGMD2I) is caused by mutations in the fukutin-related protein gene FKRP, which is also involved in congenital muscular dystrophy (MDC1C). OBJECTIVE: To evaluate the clinical, biological, radiological and mutational characteristics of LGMD2I patients with FKRP mutation. METHODS: Eleven patients from nine families from the north of France were studied. Demographical data, muscular testing results, cardiac and respiratory examinations, muscle histological features and a genetic analysis of the FKRP gene for each patient are reported. Eight patients underwent brain MRI and seven neuropsychological tests. RESULTS: The patients included six women and five men. The mean age at onset was 9 years (range 1.5 to 23 years). Five patients remained self-ambulatory, whereas the other six were confined to a wheelchair by a mean age of 19 years, after a mean disease duration of 10 years. Nine patients suffered from restrictive respiratory insufficiency, and two male patients had severe dilated cardiomyopathy. Neuropsychological tests revealed memory impairment in four cases. Brain MRI revealed cerebral abnormalities in four patients (4/8). Ten patients were carriers of the common L276I mutation, which was either homozygous (four patients) or heteroallelic with another mutation (six patients). Among the mutations found, three were novel: L322V, L489R and R275G. CONCLUSIONS: This study reveals inter- and intrafamilial phenotypic variability in LGMD2I, with a preponderance of myocardiopathy and restrictive respiratory insufficiency. It also demonstrates central nervous involvement, probably associated with changes in alpha-dystroglycan expression in the brain.

[Encopresis revealing myotonic dystrophy in 2 children]. / Encoprésie révélatrice d'une dystrophie myotonique de Steinert : à propos de 2 observations.

Gastrointestinal symptoms are very frequent in myotonic dystrophy but largely unrecognized. They can be the revealing factors of the disease. We report 2 cases of 10 and 17-year-old children with persistent encopresis starting at the age of 3 and 5 years in spite of laxative treatment. Neurological examination and anorectal manometry provided the diagnosis of myotonic dystrophy. Procainamide treatment was introduced and the digestive symptoms improved. Any child with encopresis should have complete evaluation to rule out the diagnosis of myotonic dystrophy and physicians should look for upper and/or lower gastrointestinal symptoms in every patient with myotonic dystrophy.

Childhood spinal muscular atrophy induces alterations in contractile and regulatory protein isoform expressions.

AIMS: Although modifications of the survival motor neurone gene are responsible for most spinal muscular atrophy (SMA) cases, the molecular pathophysiology and the muscular target proteins involved are still unknown. The aim of this study was to compare the expression of contractile and regulatory protein isoforms in quadriceps muscles from SMA children with age-matched control quadriceps. METHODS: The isoform patterns of myosin heavy chains (MHC), troponin subunits (T, C and I) and tropomyosin were determined by immunoblotting, reverse transcription-polymerase chain reaction and mass spectrometry analyses. Depending on the disease severity, their expression levels were followed in specific variants of SMA populations (types I, II and III), with comparison with age-matched control muscles. RESULTS: The isoform transitions in SMA muscles were different from the fast-to-faster transitions occurring in normal muscles from children aged 1 month to 5 years old. Moreover, the expression of the neonatal MHC isoform was not repressed in SMA muscles. CONCLUSIONS: The presence of the neonatal MHC isoform in SMA muscles indicates an alteration of the phenotype in these diseased muscles. It is strongly suggested that MHC and troponin T proteins may be good markers for the SMA pathology.

[Interest of the ketogenic diet in a refractory status epilepticus in adults]. / Intérêt du régime cétogène dans le traitement d'un état de mal épileptique résistant de l'adulte.

INTRODUCTION: Ketogenic diets have been employed for the treatment of intractable epilepsy in children since 1921, although underlying mechanism remains unknown. OBSERVATION: We report the case of a 54-year-old man with partial refractory status epilepticus who exhibited a favourable outcome about seven days after introduction of a ketogenic diet in association with antiepileptic drugs. DISCUSSION: Although its efficiency was largely demonstrated in children, little is known about the impact of a ketogenic diet in adults with refractory epilepsy. CONCLUSION: Introduction of a ketogenic diet requires a multidisciplinary approach. Its usefulness in adult intractable epilepsy and/or refractory status epilepticus merits further study into its efficacy in reducing the frequency of seizures and a possible prolonged effect.

[Chronic daily headache in children and adolescents]. / Les céphalées chroniques quotidiennes de l'enfant et de l'adolescent.

Chronic daily headache (CDH) affects 2-4% of adolescent females and 0.8-2% of adolescent males. Chronic daily headache is diagnosed when headaches occur more than 4h/day, 15 headache days per month or more, over a period of 3 consecutive months, without an underlying pathology. It is manifested by severe intermittent, migraine-like headaches as well as by chronic baseline headaches. Both Silberstein-Lipton criteria and the second edition of the International Classification of Headache Disorders (ICHD) can be used to classify chronic daily headache in children and adolescents. Chronic daily headache is classified into four diagnostic categories: transformed (Silberstein-Lipton criteria)/chronic (ICHD) migraine, chronic tension-type headache, new daily persistent headache, and hemicrania continua. Children and adolescents with chronic daily headache frequently have sleep disturbance, pain at other sites, dizziness, medication-overuse headache, and a psychiatric comorbidity (anxiety and mood disorders). Chronic daily headache frequently results in school absence. Successful approaches to treatment include reassurance, education, use of preventative medication, avoidance of analgesics, and helping the child return to a functional daily routine and a regular school schedule.

[Phenotypic aspects of FKRP-linked muscular dystrophy type 2I in a series of eleven patients]. / Les aspects phénotypiques de la dystrophie musculaire de type 2I liée au gène FKRP dans une série de 11 patients.

INTRODUCTION: Limb-girdle muscular dystrophy type 2I (LGMD2I) is caused by mutations in the fukutin related protein gene (FKRP gene). This study tries to evaluate clinical, biological and mutational characteristics of LGMD2I. PATIENTS AND METHODS: Eleven patients belonging to 9 families from the North of France were selected. We reported demographic data, and results of muscular testing, cardiac, and respiratory examination, as well as the histopathological features of muscle tissue and a genetic analysis of FKRP gene for each patient. RESULTS: There were 6 females and 5 males. Mean age at onset was 9.7 years old. Six had Duchenne like phenotype, 5 Becker like phenotype. Nine patients suffered from restrictive respiratory failure, two males had severe dilated cardiomyopathy. Ten patients had the common L276I mutation. Three mutations had not been previously identified: L322V, L489R and R275G heterozygous mutations associated with the L276I mutation. CONCLUSION: This study underlines inter and intra familial phenotypic variability in LGMD2I, preponderance of cardiomyopathy in males and restrictive respiratory insufficiency in female.

[Effect of thoracic bracing on lung function in children with neuromuscular disease]. / Impact du corset thoracique sur la fonction respiratoire chez des enfants atteints de maladie neuromusculaire.

UNLABELLED: Respiratory muscle weakness associated with scoliosis in neuromuscular disease leads to respiratory impairment. Children with scoliosis are usually treated with spinal bracing to delay the progress of disease. We studied the impact of spinal bracing on lung function in these children. METHODS: Retrospective study of patient data from January 1997 to January 2003. Spirometry and measurement of lung volume involved 32 observations, corresponding to 17 children with neuromuscular disease, including 14 with spinal muscular atrophy. Data for children with and without a brace were studied. RESULTS: A total of 72% of the children had severe scoliosis (Cobb score>30 degrees ); 40% wore a Garchois brace. Children without a brace showed a mean vital capacity of 65% of predicted value, with a restrictive syndrome in 44% of observations. Children with a brace showed significantly reduced vital capacity (-4.6%; P<0.001) and forced expiratory volume in 1 s (-4.6%; P=0.002). The reduced vital capacity was lower in children with the Garchois brace: -1% (P=0.02). Severity of scoliosis and measured volumes were not related. CONCLUSION: Spinal bracing in children with neuromusclar disease leads to significant respiratory impairment. Assessment of pulmonary function is necessary when a brace is indicated. The Garchois brace might lead to less impairment of respiratory function.

'Cap myopathy': case report of a family.

We report the observation of an 18-year-old girl, whose clinical presentation was very suggestive of a congenital myopathy with neonatal onset. A congenital myopathy had been already diagnosed in her brother and in addition her half-cousin died diagnosed with a severe nemaline myopathy at age 4 years. A muscle biopsy performed on both siblings revealed histological and ultrastructural features of 'cap myopathy'. This case report suggests that 'cap myopathy' and some cases of nemaline myopathy with neonatal onset might be two phenotypic expressions of the same genetic disorder. These two entities could therefore, perhaps, be regarded as 'Z-line disorders' possibly caused by defective myofibrillogenesis.

[Presentation of Niemann-Pick type C disease with psychiatric disturbance in an adult]. / Troubles psychiatriques révélateurs d'une maladie de Niemann-Pick de type C à l'âge adulte.

INTRODUCTION: Niemann-Pick Type C disease (NPC) is an autosomal recessive neurovisceral lysosomal lipid storage disorder. CASE REPORT: A 31-year-old right-handed woman had suffered from schizophrenia for 13 years. At 25 years of age, she developed a gait disorder with a static and kinetic cerebellar syndrome, dysarthria, vertical supranuclear gaze palsy and cognitive impairment. Brain MRI was normal. Abdominal ultrasonography was performed because of hypercholesterolemia and elevated transaminases and revealed hepatosplenomegaly, which in conjunction with other signs and symptoms, suggested the diagnosis of NPC. The diagnosis was confirmed by demonstration of lysosomal storage of unesterified cholesterol (filipin staining) and of a reduced rate of LDL-induced cholesterol esterification. Implication of the NPC1 gene was assessed by genetic complementation analysis. DISCUSSION: The phenotypic presentation of NPC is remarkably variable. The rarer adult-onset form has a slowly progressive course. Psychotic manifestations are often prominent and may precede neurologic symptoms. Exposure to neuroleptics delays the diagnosis of NPC. CONCLUSION: Psychotic manifestations associated with cerebellar syndrome, vertical supranuclear gaze palsy, and splenomegaly are very suggestive of NPC disease which can be reliably diagnosed on cultured skin fibroblasts by filipin staining.

[Neuropediatric approach to autism]. / Approche neuropédiatrique de l'autisme.

Autism is defined by 3 main criteria: disturbance of reciprocal social interaction, disturbance of communication (including language comprehension and spoken language) and disturbance of normal variation in behaviour and imaginative activities; an onset before age 36 months is also required. The neuropediatric contribution to autism is dominated by the search for an underlying organic etiology, especially if there are arguments for an associated encephalopathy: ante- or perinatal medical history, dysmorphic signs, skin spots, neurological abnormalities, somatic abnormalities compatible with a neurometabolic disorder. The main associated conditions with autism are: chromosome anomalies, monogenic syndrome (including fragile X syndrome), neurocutaneous syndromes, epileptic encephalopathies, neurometabolic diseases, and dystrophinopathies. The identification of an associated medical condition to autism is primordial in prospect of genetic counselling, and by the change induced in familial perception of autism.

[Central manifestations of dystrophinopathies]. / Manifestations centrales des dystrophinopathies.

The dystrophin gene involved in Duchenne and Becker muscular dystrophy is expressed in three main tissues resulting in clinical manifestations: skeletal muscle, heart and central nervous system. The 6 different existing dystrophins in the brain may play a role in the maturation and plasticity of neuronal synapses in particular by their functions in clustering and stabilization of different receptors at the post synaptic membrane. The possibility of an intellectual deficiency in Duchenne muscular dystrophy is known from the original description by Duchenne himself. Current data are in line with a constant cognitive impairment with a Gaussian curve shifted intellectual quotient (IQ) at -1 standard deviation from the standard population with an average IQ around 80. Clinical manifestations suggestive of a central nervous system involvement can affect all dystrophinopathies, including isolated central presentations without myopathic sign. The phenotypic spectrum appears broader and more subtle than non specific intellectual deficiency. The isolated or shared involvement of specific cognitive functions is possible (memory functions, executive functions, attention) with or without intellectual deficiency. Autism spectrum disorders are also among the encountered events. In clinical practice, it seems worth to ask for a measurement of serum creatine kinase (CK) in these different situations, keeping in mind that pure forms of central dystrophinopathies with a normal CK level have been recently reported.

Botulinum toxin treatment of pes cavovarus in a child suffering from autosomal recessive axonal Charcot-Marie-Tooth neuropathy (AR-CMT2).

In a 12-year old girl suffering from autosomal recessive axonal Charcot-Marie-Tooth (CMT) neuropathy, pes cavovarus was treated with botulinum toxin injection in the tibialis posterior. The patient underwent a clinical evaluation, video analysis of spatiotemporal gait parameters and dynamic foot plantar pressure assessment before treatment and then two weeks, three months and six months thereafter. The video gait analysis revealed a decrease in varus during the swing phase of gait. The dynamic foot plantar pressure decreased by 50% in the excessive pressure at the side of the foot six months after the injection (maximal pressure=42.6N/cm2 before treatment and 18.9 N/cm2 after 6 month). Botulinum toxin injection appears to be an efficacious means of correcting pes cavovarus in CMT disease. A larger-scale clinical trial is now required to evaluate the putative longer-term preventive effect of this treatment on the pes cavus deformity.

[Organization of collaborative deliberation for limiting or withholding treatments in children]. / Comment organiser la délibération collégiale pour limiter ou arrêter les traitements en pédiatrie?

In 2005, the French law on patients' rights at the end of life required that decisions to withdraw or withhold life-sustaining treatments be made and carried out by the physician in charge of the patient, after obtaining advice from an independent consulting colleague and the caregiving team. The purpose of this study was to identify theoretical and practical obstacles to this collaborative deliberation and to propose practical guidelines to organize it.

Patients with familial partial lipodystrophy of the Dunnigan type due to a LMNA R482W mutation show muscular and cardiac abnormalities.

Diseases due to mutations in the lamin A/C gene (LMNA) are highly heterogeneous, including neuromuscular and cardiac dystrophies, lipodystrophies, and premature ageing syndromes. In this study we characterized the neuromuscular and cardiac phenotypes of patients bearing the heterozygous LMNA R482W mutation, which is the most frequent genotype associated with the familial partial lipodystrophy of the Dunnigan type (FPLD). Fourteen patients from two unrelated families, including 10 affected subjects, were studied. The two probands had been referred for lipoatrophy and/or diabetes. Lipodystrophy, exclusively observed in LMNA-mutated patients, was of variable severity and limited to postpubertal subjects. Lipodystrophy and metabolic disturbances were more severe in women, even if an enlarged neck was a constant finding. The severity of hypertriglyceridemia and hirsutism in females was related to that of insulin resistance. Clinical muscular alterations were only present in LMNA-mutated patients. Clinical and histological examination showed an invalidating, progressive limb-girdle muscular dystrophy in a 42-yr-old woman that had been present since childhood, associated with a typical postpubertal FPLD phenotype. Six of eight adults presented the association of calf hypertrophy, perihumeral muscular atrophy, and a rolling gait due to proximal lower limb weakness. Muscular histology was compatible with muscular dystrophy in one of them and/or showed a nonspecific excess of lipid droplets (in three cases). Immunostaining of lamin A/C was normal in the six muscular biopsies. Surprisingly, calpain 3 expression was undetectable in the patient with the severe limb-girdle muscular dystrophy, although the gene did not reveal any molecular alterations. At the cardiac level, cardiac septal hypertrophy and atherosclerosis were frequent in FPLD patients. In addition, a 24-yr-old FPLD patient had a symptomatic second degree atrioventricular block. In conclusion, we showed that most lipodystrophic patients affected by the FPLD-linked LMNA R482W mutation show muscular and cardiac abnormalities. The occurrence and severity of the myopathic and lipoatrophic phenotypes varied and were not related. The muscular phenotype was evocative of limb girdle muscular dystrophy. Cardiac hypertrophy and advanced atherosclerosis were frequent. FPLD patients should receive careful neuromuscular and cardiac examination whatever the underlying LMNA mutation.

[Benign reflex myoclonic epilepsy in infants]. / L'épilepsie myoclonique bénigne réflexe du nourrisson.

BACKGROUND: Myoclonic epilepsy of infancy are seldom benign. CASE REPORT: A 25-month old girl developed myoclonic jerks either spontaneously either as reflex responses to auditory and tactile stimuli, such as sudden touching of the face or trunk from the age of 4 months. The jerks disappeared after valproate therapy. Neurological examination was normal with a follow-up of 9 months. CONCLUSION: This condition resembles that described in 1995 by Ricci et al. In must be differentiated from other myoclonic epilepsies of infancy, reflex epilepsies and hyperekplexia. It could be the earliest from of idiopathic generalized epilepsy.