Expanding the spectrum of CEP55-associated disease to viable phenotypes.

Homozygosity for nonsense variants in CEP55 has been associated with a lethal condition characterized by multinucleated neurons, anhydramnios, renal dysplasia, cerebellar hypoplasia, and hydranencephaly (MARCH syndrome) also known as Meckel-like syndrome. Missense variants in CEP55 have not previously been reported in association with disease. Here we describe seven living individuals from five families with biallelic CEP55 variants. Four unrelated individuals with microcephaly, speech delays, and bilateral toe syndactyly all have a common CEP55 variant c.70G>A p.(Glu24Lys) in trans with nonsense variants. Three siblings are homozygous for a consensus splice site variant near the end of the gene. These affected girls all have severely delayed development, microcephaly, and varying degrees of lissencephaly/pachygyria. Here we compare our seven patients with three previously reported families with a prenatal lethal phenotype (MARCH syndrome/Meckel-like syndrome) due to homozygous CEP55 nonsense variants. Our series suggests that individuals with compound heterozygosity for nonsense and missense variants in CEP55 have a different viable phenotype. We show that homozygosity for a splice variant near the end of the CEP55 gene is also compatible with life.

Imatinib mesylate for plexiform neurofibromas in patients with neurofibromatosis type 1: a phase 2 trial.

BACKGROUND: Plexiform neurofibromas are slow-growing chemoradiotherapy-resistant tumours arising in patients with neurofibromatosis type 1 (NF1). Currently, there are no viable therapeutic options for patients with plexiform neurofibromas that cannot be surgically removed because of their proximity to vital body structures. We undertook an open-label phase 2 trial to test whether treatment with imatinib mesylate can decrease the volume burden of clinically significant plexiform neurofibromas in patients with NF1. METHODS: Eligible patients had to be aged 3-65 years, and to have NF1 and a clinically significant plexiform neurofibroma. Patients were treated with daily oral imatinib mesylate at 220 mg/m(2) twice a day for children and 400 mg twice a day for adults for 6 months. The primary endpoint was a 20% or more reduction in plexiform size by sequential volumetric MRI imaging. Clinical data were analysed on an intention-to-treat basis; a secondary analysis was also done for those patients able to take imatinib mesylate for 6 months. This trial is registered with ClinicalTrials.gov, number NCT01673009. FINDINGS: Six of 36 patients (17%, 95% CI 6-33), enrolled on an intention-to-treat basis, had an objective response to imatinib mesylate, with a 20% or more decrease in tumour volume. Of the 23 patients who received imatinib mesylate for at least 6 months, six (26%, 95% CI 10-48) had a 20% or more decrease in volume of one or more plexiform tumours. The most common adverse events were skin rash (five patients) and oedema with weight gain (six). More serious adverse events included reversible grade 3 neutropenia (two), grade 4 hyperglycaemia (one), and grade 4 increases in aminotransferase concentrations (one). INTERPRETATION: Imatinib mesylate could be used to treat plexiform neurofibromas in patients with NF1. A multi-institutional clinical trial is warranted to confirm these results. FUNDING: Novartis Pharmaceuticals, the Indiana University Simon Cancer Centre, and the Indiana University Herman B Wells Center for Pediatric Research.

Is it ADEM, POLG, or both?

OBJECTIVE: To describe a child with apparent brain biopsy-confirmed acute disseminated encephalomyelitis (ADEM) but genetic confirmation of compound heterozygosity for DNA mutations of the polymerase gamma (POLG) gene. DESIGN: Case report. SETTING: Tertiary referral center. PATIENT: A 4-year-old boy presented with ataxia and encephalopathy. RESULTS: Magnetic resonance imaging demonstrated multiple focal areas of T2 prolongation. The patient's family refused steroid treatment. His symptoms improved then progressed. Magnetic resonance imaging findings also progressed. A cerebrospinal fluid specimen revealed myelin basic protein and oligoclonal bands. A brain biopsy specimen demonstrated demyelination, suggesting progression of ADEM. However, polymerase chain reaction amplification and sequencing revealed 2 heterozygous mutations of the POLG gene, suggesting mitochondrial disease. The patient died 9 months after his initial presentation. CONCLUSIONS: This case raises interesting questions about whether ADEM triggered severe neurologic degeneration in a patient with mitochondrial disease, whether mitochondrial disease predisposed to a pathologic immune response, or whether mitochondrial disease can mimic an autoimmune disease. Mitochondrial disease-causing mutations may help explain the poor outcome in some cases of apparent autoimmune central nervous system disease.

Rituximab for the treatment of thymoma-associated and de novo myasthenia gravis: 3 cases and review.

OBJECTIVES: Myasthenia gravis (MG) is an immune-mediated disorder associated with autoantibodies against postsynaptic nicotinic acetylcholine receptors at neuromuscular junctions. Rituximab, a monoclonal antibody specific for CD20, is used primarily to treat B-cell non-Hodgkin lymphoma. Although it has been used for treatment of a number of autoimmune diseases, there is limited experience in MG. METHODS: Three patients with refractory MG (2 with concurrent thymoma) were given rituximab. RESULTS: Symptoms stabilized and reductions in immunosuppressive medications were tolerated for extended periods, without adverse effects or infectious complications. CONCLUSIONS: These observations support the concept that rituximab may be helpful for the treatment of MG. Remissions in patients with or without thymoma are achievable with rituximab given in combination with commonly used modalities. Furthermore, rituximab is not necessarily contraindicated for the treatment of MG in patients being treated for thymoma. Controlled studies are called for to define its role in the treatment of refractory MG.

Simultaneous toxicities in a child on multiple anticonvulsants.

It is rare to develop simultaneous toxicities while on anticonvulsants. This article presents a 3(1/2)-year-old child on valproic acid, lamotrigine, and phenytoin who developed simultaneous hepatotoxicity and bone marrow toxicity during a parainfluenza virus type 3 infection. These toxicities resolved after the cessation of anticonvulsants, and her seizures were managed acutely with scheduled lorazepam. This article discusses the possibility that simultaneous use of valproic acid, lamotrigine, and phenytoin could give this combination of toxicities and that concurrent viral infection may increase this risk.

Two cases further delineating the Sakoda complex.

Sakoda complex consists of sphenoethmoidal encephalomeningocele, agenesis of the corpus callosum, and cleft lip and/or palate. Associated abnormalities include optic disc dysplasia, microphthalmia, cortical dysgenesis, mental retardation and epilepsy. The etiology remains unknown. We describe two patients with anomalies consistent with the Sakoda complex including the cardinal features of sphenoethmoidal encephalomeningocele and cleft palate. The first patient also has right microphthalmia, optic nerve hypoplasia, diffuse pachygyria, asymmetric ventricles, atrial septal defect, hemivertebrae, and renal abnormalities. The second patient has right microphthalmia, absence of the right hemisphere, and a right bifid thumb. The features of Sakoda complex present in these patients may also overlap with frontonasal dysplasia and morning glory syndrome suggesting shared pathogenic relationships. We propose that the primary malformation of the Sakoda complex is probably genetic. The right hemispheric defect in Patient 2 suggests that at least some cases of Sakoda complex may also be associated with vascular disruption. Thus, more than one pathogenetic process contributes to the phenotypic spectrum of Sakoda complex.