Rituximab in juvenile myasthenia gravis-an international cohort study and literature review.

Juvenile myasthenia gravis (JMG) is a rare, antibody-mediated disorder of the neuromuscular junction. Treatment strategies in JMG are largely informed by adult MG treatments as the pathophysiology is similar. Rituximab is increasingly considered as a treatment option in refractory JMG but has not yet been systematically investigated in this patient group We conducted a retrospective study from five international centres with expertise in paediatric myasthenia. 10 JMG patients treated with rituximab were identified. Following rituximab treatment all patients had a reduction in JMG-related hospital admissions. At 24 month follow up, 6 patients (60%) had achieved complete stable remission or pharmacological remission and 7 patients were able to reduce immunomodulatory treatment(s). The main side-effect was infusion-related reactions (30%) which resolved in all patients with symptomatic treatment. We compared our cohort to previously reported JMG cases treated with rituximab and noted similar response rates but a slightly higher side-effect profile. Rituximab is a safe and effective treatment option in moderate to severe JMG and most patients have an improvement in MG symptoms post treatment.

Homozygous intronic variants in TPM2 cause recessively inherited Escobar variant of multiple pterygium syndrome and congenital myopathy.

Pathogenic variants in TPM2 have been associated with a variable clinical spectrum, including congenital myopathies and distal arthrogryposis, all but one with dominant inheritance. We report the second case of recessively inherited TPM2-related Escobar variant of multiple pterygium syndrome and congenital myopathy in a patient from a consanguineous family. Ultra-structural examination of the biopsy revealed few cores/mini-cores and sparse nemaline rods. We found a novel homozygous intronic sequence variant, c.564-2A>C in TPM2. This variant is predicted to abolish the consensus acceptor splice site for exon 6b of TPM2 gene. Parents of the proband, both healthy adults with no clinical features, were heterozygous for the variant. Here we establish a homozygous intronic variant in TPM2 as the likely cause of Escobar variant of multiple pterygium syndrome and congenital myopathy, with sparse nemaline rods.

Respiratory Trajectories in Type 2 and 3 Spinal Muscular Atrophy in the iSMAC Cohort Study.

OBJECTIVE: To describe the respiratory trajectories and their correlation with motor function in an international pediatric cohort of patients with type 2 and nonambulant type 3 spinal muscular atrophy (SMA). METHODS: This was an 8-year retrospective observational study of patients in the International SMA Consortium (iSMAc) natural history study. We retrieved anthropometrics, forced vital capacity (FVC) absolute, FVC percent predicted (FVC%P), and noninvasive ventilation (NIV) requirement. Hammersmith Functional Motor Scale (HFMS) and revised Performance of Upper Limb (RULM) scores were correlated with respiratory function. We excluded patients in interventional clinical trials and on nusinersen commercial therapy. RESULTS: There were 437 patients with SMA: 348 with type 2 and 89 with nonambulant type 3. Mean age at first visit was 6.9 (±4.4) and 11.1 (±4) years. In SMA type 2, FVC%P declined by 4.2%/y from 5 to 13 years, followed by a slower decline (1.0%/y). In type 3, FVC%P declined by 6.3%/y between 8 and 13 years, followed by a slower decline (0.9%/y). Thirty-nine percent with SMA type 2% and 9% with type 3 required NIV at a median age 5.0 (1.8-16.6) and 15.1 (13.8-16.3) years. Eighty-four percent with SMA type 2% and 80% with type 3 had scoliosis; 54% and 46% required surgery, which did not significantly affect respiratory decline. FVC%P positively correlated with HFMS and RULM scores in both subtypes. CONCLUSIONS: In SMA type 2 and nonambulant type 3, lung function declines differently, with a common leveling after age 13 years. Lung and motor function correlated in both subtypes. Our data further define the milder SMA phenotypes and provide information to benchmark the long-term efficacy of new treatments for SMA.

Is chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) in children the same condition as in adults?

This case series describes three children with chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS), an inflammatory condition characterized by a relapsing-remitting disease course responsive to steroids. The patients (two males, age 3y and 13y; one female, age 14y) presented with ataxia, dysarthria, and multiple cranial neuropathies. All patients demonstrated bilateral nodular lesions with contrast enhancement in the brainstem and cerebellum on magnetic resonance imaging, and perivascular lymphocytes and macrophages infiltrates on brain biopsies. Despite an initially good response to corticosteroids, all patients eventually became steroid-dependent or -resistant, with frequent relapses on maintenance immunosuppressive therapy. Natalizumab and intravenous immunoglobulin stopped neurological disease progression in Patient 1 but he died at 17 years from respiratory complications. Patient 2 went into remission on infliximab and intravenous methylprednisolone for several months but was then diagnosed with Epstein-Barr virus driven B-cell lymphoma 3 years after symptom onset. Patient 3 failed to respond to treatment and died 4 years after diagnosis. CLIPPERS disease in children is aggressive, with poor response to immunotherapy. Earlier use of newer immunotherapeutic agents such as natalizumab may be beneficial. Potential side effects need to be considered carefully. WHAT THIS PAPER ADDS: Paediatric chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) appears a more severe condition than previously reported in adults. Aggressive treatment before neuroaxonal loss may be required for a better outcome.

¿ES LA INFLAMACIÓN LINFOCÍTICA CRÓNICA CON REALCE PERIVASCULAR PONTINO SENSIBLE A LOS ESTEROIDES (CLIPPERS) EN LOS NIÑOS CON LA MISMA CONDICIÓN QUE EN LOS ADULTOS?: Esta serie de casos describe a tres niños con inflamación linfocítica crónica con realce pontinal perivascular sensible a esteroides (CLIPPERS), una enfermedad inflamatoria caracterizada por un curso de enfermedad recurrente-remitente sensible a los esteroides. Los pacientes (dos varones, edad 3 y 13 años, una mujer, edad 14 años) presentaron ataxia, disartria y neuropatías craneales múltiples. Todos los pacientes demostraron lesiones nodulares bilaterales con realce de contraste en el tallo cerebral y el cerebelo en imágenes de resonancia magnética y linfocitos perivasculares y infiltrados de macrófagos en biopsias cerebrales. A pesar de una respuesta inicialmente buena a los corticosteroides, todos los pacientes finalmente se volvieron dependientes de esteroides o resistentes, con recaídas frecuentes en la terapia inmunosupresora de mantenimiento. El natalizumab y la inmunoglobulina intravenosa suspendieron la progresión de la enfermedad neurológica en el paciente 1, pero falleció a los 17 años por complicaciones respiratorias. El paciente 2 entró en remisión con infliximab y metilprednisolona por vía intravenosa durante varios meses, pero luego se le diagnosticó linfoma de células B dirigido por el virus de Epstein-Barr, 3 años después del inicio de los síntomas. El paciente 3 no respondió al tratamiento y murió 4 años después del diagnóstico. La enfermedad de CLIPPERS en los niños es agresiva, con una respuesta deficiente a la inmunoterapia. El uso previo de agentes inmunoterápicos más nuevos como natalizumab puede ser beneficioso. Los posibles efectos secundarios deben considerarse cuidadosamente.

A INFLAMAÇÃO LINFOCÍTICA CRÔNICA COM REALCE PERIVASCULAR PONTINO RESPONSIVA A ESTERÓIDES (CLIPPERS) É A MESMA CONDIÇÃO EM CRIANÇAS E ADULTOS?: Esta série de casos descreve três crianças com inflamação linfocítica crônica com realce perivascular pontino responsiva a esteróides (CLIPPERS), uma condição inflamatória caracterizada por uma doença com curso remissivo-recidivante responsive a esteróides. Os pacientes (dois meninos, idades 3 e 13 anos; uma menina, idade 14 anos) apresentaram ataxia, disartria, e múltiplas neuropatias craniais. Todos os pacientes demonstraram lesões nodulares bilaterais com realce no tronco cerebral e cerebelo ao exame ne ressonância magnética, e infiltrados perivasculares de linfócitos e macrófagos nas biópsias cerebrais. Apesar de uma resposta inicialmente boa aos corticoesteróides, todos os pacientes eventualmente se tornaram esteróide-dependentes ou resistentes, com frequentes recidivas com manutenção de imunoterapia supressora. Natalizumab e imunoglobulina intravenosa interromperam a progressão neurológica da doença no Paciente 1, mas ele veio a óbito na idade de 17 anos devido a complicações respiratórias. O Paciente 2 entrou em remissão com infliximab e metilprednosolona intravenosa por vários meses, mas foi então diagnosticado com linfoma de células B causado por virus Epstein-Barr 3 anos após o início dos sintomas. O Paciente 3 não respondeu ao tratamento e veio a óbito 4 anos após o diagnóstico. Patient 2 went into remission on infliximab and intravenous methylprednisolone for several months but was then diagnosed with Epstein-Barr virus driven B-cell lymphoma 3 years after symptom onset. Patient 3 failed to respond to treatment and died 4 years after diagnosis. INTERPRETAÇÃO: A doença CLIPPERS em crianças é agressiva, com pouca resposta à imunoterapia. O uso precoce de agentes imunoterapêuticos mais novos como natalizumab pode ser benéfico. Potenciais efeitos colaterais devem ser considerados com cautela.

Whole Exon Deletion in the GFAP Gene Is a Novel Molecular Mechanism Causing Alexander Disease.

Alexander disease (AD) is a leukodystrophy caused by heterozygous mutations in the gene encoding the glial fibrillary acidic protein (GFAP). Currently, de novo heterozygous missense mutations in the GFAP gene are identified in over 95% of patients with AD. However, patients with biopsy-proven AD have been reported in whom no GFAP mutation has been identified. We report identical twin boys presenting in infancy with seizures and developmental delay in whom MR appearances were suggestive of AD with the exception of an unusual, bilateral, arc of calcification at the frontal white-gray junction. Initial mutation screening of the GFAP gene did not identify a mutation. Whole exome sequencing in both brothers revealed a de novo heterozygous in-frame deletion of the whole of exon 5 of the GFAP gene. Mutations in the GFAP gene are thought to result in a toxic effect of mutant GFAP disrupting the formation of the normal intermediate filament network and resulting in Rosenthal fiber formation, which has hitherto not been linked to exonic scale copy number variants in GFAP. Further studies on mutation negative AD patients are warranted to determine whether a similar mechanism underlies their disease.

Homozygous deletion in MICU1 presenting with fatigue and lethargy in childhood.

OBJECTIVE: To define the mechanism responsible for fatigue, lethargy, and weakness in 2 cousins who had a normal muscle biopsy. METHODS: Exome sequencing, long-range PCR, and Sanger sequencing to identify the pathogenic mutation. Functional analysis in the patient fibroblasts included oxygen consumption measurements, extracellular acidification studies, Western blotting, and calcium imaging, followed by overexpression of the wild-type protein. RESULTS: Analysis of the exome sequencing depth revealed a homozygous deletion of exon 1 of MICU1 within a 2,755-base pair deletion. No MICU1 protein was detected in patient fibroblasts, which had impaired mitochondrial calcium uptake that was rescued through the overexpression of the wild-type allele. CONCLUSIONS: MICU1 mutations cause fatigue and lethargy in patients with normal mitochondrial enzyme activities in muscle. The fluctuating clinical course is likely mediated through the mitochondrial calcium uniporter, which is regulated by MICU1.

A cohort study of children and young people with progressive neuromuscular disorders: clinical and demographic profiles and changing patterns of referral for palliative care.

BACKGROUND: Progressive neuromuscular disease in children is life limiting and these children and young people would benefit from palliative care services, but data are limited on the number and demography of these children. AIM: To describe the clinical and demographic profile of children referred to a Children's hospice in the UK with progressive neuromuscular disease. SETTING/PARTICIPANTS: All children and young people with progressive neuromuscular disorders referred to Martin House Children's Hospice between 1987 and 2010. DESIGN: Retrospective cohort study. RESULTS: 300 children with progressive neuromuscular disease were referred to the hospice. Seventy percent (210) of these children had Duchenne Muscular Dystrophy, 22% (67) had Spinal Muscular Atrophy (34 with Type I) and 8% had other neuromuscular diseases. Numbers of referrals have not significantly increased over the last 15 years, although an increasing number come from a South Asian background (from 4% to 32%) and a higher number of children have conditions other than Duchenne Muscular Dystrophy. A total of 55.3% (166) of all referrals came from areas of the highest deprivation. Survival patterns varied by diagnostic group, but ethnicity and deprivation were not associated with survival in these children. CONCLUSIONS: The profile of children with progressive neuromuscular conditions who were referred for palliative care has changed over the last 20 years, with a different spectrum of underlying diagnoses and a greater number from a South Asian background. The higher than expected proportion of children living in areas of high deprivation has been consistent over time.

Diffuse hemispheric dysembryoplastic neuroepithelial tumor: a new radiological variant associated with early-onset severe epilepsy.

The authors describe the clinical and radiological features in 3 children with a diffuse hemispheric dysembryoplastic neuroepithelial tumor (DNET) presenting with severe epilepsy and a previously unreported and characteristic MR imaging appearance. The DNET is a well-recognized cause of focal epilepsy, usually with a very good response to resection. These tumors are usually intracortical, and most commonly arise in the temporal lobe or frontal lobes. Radiologically they are usually sharply demarcated, and show little contrast enhancement. Three children (2 boys and 1 girl) presented at 14, 17, and 22 months of age with epileptic seizures. The seizures were focal motor or complex focal. One patient had epileptic spasms. The response to antiepileptic drug therapy was poor. Motor and cognitive development was delayed in all patients. One patient developed a severe epileptic encephalopathy, with regression of motor and cognitive skills. Her electroencephalogram obtained at that time showed hypsarhythmia. Admission MR imaging showed a diffuse unilateral abnormality involving frontal, temporal, and parietal lobes with little or no mass effect. There was involvement of both gray and white matter, with a striking sparing of the internal capsule in spite of apparent tumor throughout the basal ganglia and thalamus. In 2 patients there was prominent expansion of cortical gyri by tumor. In 1 child the initial radiological diagnosis was a middle cerebral artery infarct. On subsequent review the radiological diagnosis was thought to be low-grade glioma in all patients. The first patient underwent 2 limited resections involving the temporal lobe. He has continued to have poorly controlled seizures and severe behavioral and cognitive problems. The other patients had subtotal resection to the level of the internal capsule. One patient is currently seizure free 24 months postsurgery, but remains cognitively impaired. The patient in Case 3 is having some seizures 3.5 years postsurgery and remains hemiplegic, but the regression has reversed and she is making steady developmental progress. The pathological specimens showed the typical features of a DNET in all cases. This striking radiological pattern has not previously been described as a feature of a DNET. Recognition of this radiological pattern in young children with epilepsy will allow early consideration for resection, which may lead to improved long-term cognitive outcome.

Nemaline myopathy caused by absence of alpha-skeletal muscle actin.

OBJECTIVE: To investigate seven congenital myopathy patients from six families: one French Gypsy, one Spanish Gypsy, four British Pakistanis, and one British Indian. Three patients required mechanical ventilation from birth, five died before 22 months, one is ventilator-dependent, but one, at 30 months, is sitting with minimal support. All parents were unaffected. METHODS: The alpha-skeletal muscle actin gene (ACTA1) was sequenced. Available muscle biopsies were investigated by standard histological and electron microscopic techniques. The expression of various proteins was determined by immunohistochemistry, western blotting, or both. RESULTS: Three homozygous ACTA1 null mutations were identified: p.Arg41X in the French patient, p.Tyr364fsX in the Spanish patient, and p.Asp181fsX10 in all five British patients. An absence of alpha-skeletal muscle actin protein but presence of alpha-cardiac actin was shown in all muscle biopsies examined, with more alpha-cardiac actin in the biopsy from the child with the greatest muscle function. Muscle biopsies from all patients exhibited nemaline bodies whereas three also contained zebra bodies. INTERPRETATION: The seven patients have recessive nemaline myopathy caused by absence of alpha-skeletal muscle actin. The level of retention of alpha-cardiac actin, the skeletal muscle fetal actin isoform, may determine alpha-skeletal muscle actin disease severity. This has implications for possible future therapy.