356 research outputs found
Bi-allelic JAM2 Variants Lead to Early-Onset Recessive Primary Familial Brain Calcification.
Primary familial brain calcification (PFBC) is a rare neurodegenerative disorder characterized by a combination of neurological, psychiatric, and cognitive decline associated with calcium deposition on brain imaging. To date, mutations in five genes have been linked to PFBC. However, more than 50% of individuals affected by PFBC have no molecular diagnosis. We report four unrelated families presenting with initial learning difficulties and seizures and later psychiatric symptoms, cerebellar ataxia, extrapyramidal signs, and extensive calcifications on brain imaging. Through a combination of homozygosity mapping and exome sequencing, we mapped this phenotype to chromosome 21q21.3 and identified bi-allelic variants in JAM2. JAM2 encodes for the junctional-adhesion-molecule-2, a key tight-junction protein in blood-brain-barrier permeability. We show that JAM2 variants lead to reduction of JAM2 mRNA expression and absence of JAM2 protein in patient's fibroblasts, consistent with a loss-of-function mechanism. We show that the human phenotype is replicated in the jam2 complete knockout mouse (jam2 KO). Furthermore, neuropathology of jam2 KO mouse showed prominent vacuolation in the cerebral cortex, thalamus, and cerebellum and particularly widespread vacuolation in the midbrain with reactive astrogliosis and neuronal density reduction. The regions of the human brain affected on neuroimaging are similar to the affected brain areas in the myorg PFBC null mouse. Along with JAM3 and OCLN, JAM2 is the third tight-junction gene in which bi-allelic variants are associated with brain calcification, suggesting that defective cell-to-cell adhesion and dysfunction of the movement of solutes through the paracellular spaces in the neurovascular unit is a key mechanism in CNS calcification
An integrated approach to the evaluation of patients with asymptomatic or minimally symptomatic hyperCKemia
Currently, there are no straightforward guidelines for the clinical and diagnostic management of hyperCKemia, a frequent and nonspecific presentation in muscle diseases. Therefore, we aimed to describe our diagnostic workflow for evaluating patients with this condition. Methods: We selected 83 asymptomatic or minimally symptomatic patients with persistent hyperCKemia for participation in this Italian multicenter study. Patients with facial involvement and distal or congenital myopathies were excluded, as were patients with suspected inflammatory myopathies or predominant respiratory or cardiac involvement. All patients underwent a neurological examination and nerve conduction and electromyography studies. The first step of the investigation included a screening for Pompe disease. We then evaluated the patients for myotonic dystrophy type II\u2013related CCTG expansion and excluded patients with copy number variations in the DMD gene. Subsequently, the undiagnosed patients were investigated using a target gene panel that included 20 genes associated with isolated hyperCKemia. Results: Using this approach, we established a definitive diagnosis in one third of the patients. The detection rate was higher in patients with severe hyperCKemia and abnormal electromyographic findings. Discussion: We have described our diagnostic workflow for isolated hyperCKemia, which is based on electrodiagnostic data, biochemical screening, and first-line genetic investigations, followed by successive targeted sequencing panels. Both clinical signs and electromyographic abnormalities are associated with increased diagnostic yields
Alternating hemiplegia of childhood: evolution over time and mouse model corroboration
Alternating hemiplegia of childhood is a rare neurodevelopmental disorder caused by ATP1A3 mutations. Some evidence for disease progression exists, but there are few systematic analyses. Here, we evaluate alternating hemiplegia of childhood progression in humans and in the D801N knock-in alternating hemiplegia of childhood mouse, Mashlool, model. This study performed an ambidirectional (prospective and retrospective data) analysis of an alternating hemiplegia of childhood patient cohort (n = 42, age 10.24 ± 1.48 years) seen at one US centre. To investigate potential disease progression, we used linear mixed effects models incorporating early and subsequent visits, and Wilcoxon Signed Rank test comparing first and last visits. Potential early-life clinical predictors were determined via multivariable regression. We also compared EEG background at first encounter and at last follow-up. We then performed a retrospective confirmation study on a multicentre cohort of alternating hemiplegia of childhood patients from France (n = 52). To investigate disease progression in the Mashlool mouse, we performed behavioural testing on a cohort of Mashlool- mice at prepubescent and adult ages (n = 11). Results: US patients, over time, demonstrated mild worsening of non-paroxysmal disability index scores, but not of paroxysmal disability index scores. Increasing age was a predictor of worse scores: P < 0.0001 for the non-paroxysmal disability index, intellectual disability scale and gross motor scores. Earliest non-paroxysmal disability index score was a predictor of last visit non-paroxysmal disability index score (P = 0.022), and earliest intellectual disability score was a predictor of last intellectual disability score (P = 0.035). More patients with EEG background slowing were noted at last follow-up as compared to initial (P = 0.015). Similar worsening of disease with age was also noted in the French cohort: age was a significant predictor of non-paroxysmal disability index score (P = 0.001) and first and last non-paroxysmal disability index score scores significantly differed (P = 0.002). In animal studies, adult Mashlool mice had, as compared to younger Mashlool mice, (i) worse balance beam performance; (ii) wider base of support; (iii) higher severity of seizures and resultant mortality; and (iv) no increased predisposition to hemiplegic or dystonic spells. In conclusion, (i) non-paroxysmal alternating hemiplegia of childhood manifestations show, on average over time, progression associated with severity of early-life non-paroxysmal disability and age. (ii) Progression also occurs in Mashlool mice, confirming that ATP1A3 disease can lead to age-related worsening. (iii) Clinical findings provide a basis for counselling patients and for designing therapeutic trials. Animal findings confirm a mouse model for investigation of underlying mechanisms of disease progression, and are also consistent with known mechanisms of ATP1A3-related neurodegeneration
Shocks in the Stacked Sunyaev-Zel'dovich Profiles of Clusters II: Measurements from SPT-SZ + Planck Compton-y Map
We search for the signature of cosmological shocks in stacked gas pressure
profiles of galaxy clusters using data from the South Pole Telescope (SPT).
Specifically, we stack the latest Compton-y maps from the 2500 deg^2 SPT-SZ
survey on the locations of clusters identified in that same dataset. The sample
contains 516 clusters with mean mass = 1e14.9 msol and redshift =
0.55. We analyze in parallel a set of zoom-in hydrodynamical simulations from
The Three Hundred project. The SPT-SZ data show two features: (i) a pressure
deficit at R/R200m = , measured at significance and
not observed in the simulations, and; (ii) a sharp decrease in pressure at
R/R200m = at significance. The pressure deficit is
qualitatively consistent with a shock-induced thermal non-equilibrium between
electrons and ions, and the second feature is consistent with accretion shocks
seen in previous studies. We split the cluster sample by redshift and mass, and
find both features exist in all cases. There are also no significant
differences in features along and across the cluster major axis, whose
orientation roughly points towards filamentary structure. As a consistency
test, we also analyze clusters from the Planck and Atacama Cosmology Telescope
Polarimeter surveys and find quantitatively similar features in the pressure
profiles. Finally, we compare the accretion shock radius (Rsh_acc) with
existing measurements of the splashback radius (Rsp) for SPT-SZ and constrain
the lower limit of the ratio, Rsh_acc/Rsp > .Comment: [v1]: 8 Figures, 16 Pages in Main text. [v2]: Added text to
discussion. Version accepted in MNRA
Shocks in the stacked Sunyaev-Zel'dovich profiles of clusters II: Measurements from SPT-SZ + Planck Compton-y map
We search for the signature of cosmological shocks in stacked gas pressure profiles of galaxy clusters using data from the South Pole Telescope (SPT). Specifically, we stack the latest Compton-y maps from the 2500 deg2 SPT-SZ survey on the locations of clusters identified in that same data set. The sample contains 516 clusters with mean mass 〈 M 200m〉 = 1014.9\, M⊙ and redshift z= 0.55. We analyse in parallel a set of zoom-in hydrodynamical simulations from the three hundred project. The SPT-SZ data show two features: (i) a pressure deficit at R/R200m = 1.08 ± 0.09, measured at 3.1σ significance and not observed in the simulations, and; (ii) a sharp decrease in pressure at R/R200m = 4.58 ± 1.24 at 2.0σ significance. The pressure deficit is qualitatively consistent with a shock-induced thermal non-equilibrium between electrons and ions, and the second feature is consistent with accretion shocks seen in previous studies. We split the cluster sample by redshift and mass, and find both features exist in all cases. There are also no significant differences in features along and across the cluster major axis, whose orientation roughly points towards filamentary structure. As a consistency test, we also analyse clusters from the Planck and Atacama Cosmology Telescope Polarimeter surveys and find quantitatively similar features in the pressure profiles. Finally, we compare the accretion shock radius (R sh,\, acc) with existing measurements of the splashback radius (Rsp) for SPT-SZ and constrain the lower limit of the ratio, R sh,\, acc/R sp\> 2.16\± 0.59
Two novel missense mutations in the myelin protein zero gene causes Charcot-Marie-Tooth type 2 and Déjérine-Sottas syndrome
<p>Abstract</p> <p>Background</p> <p>The Charcot-Marie-Tooth (CMT) phenotype caused by mutation in the <it>myelin protein zero (MPZ) </it>gene varies considerably, from early onset and severe forms to late onset and milder forms. The mechanism is not well understood. The myelin protein zero (P<sub>0</sub>) mediates adhesion in the spiral wraps of the Schwann cell's myelin sheath. The crystalline structure of the extracellular domain of the myelin protein zero (P<sub>0</sub>ex) is known, while the transmembrane and intracellular structure is unknown.</p> <p>Findings</p> <p>One novel missense mutation caused a milder late onset CMT type 2, while the second missense mutation caused a severe early onset phenotype compatible with Déjérine-Sottas syndrome.</p> <p>Conclusions</p> <p>The phenotypic variation caused by different missense mutations in the <it>MPZ </it>gene is likely caused by different conformational changes of the MPZ protein which affects the functional tetramers. Severe changes of the MPZ protein cause dysfunctional tetramers and predominantly uncompacted myelin, i.e. the severe phenotypes congenital hypomyelinating neuropathy and Déjérine-Sottas syndrome, while milder changes cause the phenotypes CMT type 1 and 2.</p
State-of-the-art management of locally advanced head and neck cancer
During the past 20 years, treatments for head and neck squamous cell carcinoma (HNSCC) have changed dramatically owing largely to the advent of novel approaches such as combined modality therapy as well as improvements in surgical and radiotherapeutic techniques. Locally advanced disease in particular, which engendered very high recurrence and mortality rates, is now associated with long-term disease-free survival in the majority of cases. This article will focus on locally advanced HNSCC, which frequently remains a clinical challenge, review state-of-the-art therapy, and introduce promising novel therapies. The field continues to evolve rapidly with new evidence during the past year clearly establishing the benefit of adjuvant chemoradiotherapy (CRT), as well as early evidence showing improved survival with the use of an epidermal growth factor receptor inhibitor in combination with radiotherapy. There are varied regimens in use for patients with locally advanced disease, but at the same time the multitude of options can plague the clinician when trying to select the most appropriate one. This article will attempt to put the various approaches into perspective and propose an evidence-based treatment algorithm
EGFR Kinase Promotes Acquisition of Stem Cell-Like Properties: A Potential Therapeutic Target in Head and Neck Squamous Cell Carcinoma Stem Cells
Members of the EGFR/ErbB family of tyrosine kinases are found to be highly expressed and deregulated in many cancers, including head and neck squamous cell carcinoma (HNSCC). The ErbB family, including EGFR, has been demonstrated to play key roles in metastasis, tumorigenesis, cell proliferation, and drug resistance. Recently, these characteristics have been linked to a small subpopulation of cells classified as cancer stem cells (CSCs) which are believed to be responsible for tumor initiation and maintenance. In this study, we investigated the possible role of EGFR as a regulator of “stemness” in HNSCC cells. Activation of EGFR by the addition of EGF ligand or ectopic expression of EGFR in two established HNSCC cell lines (UMSCC-22B and HN-1) resulted in the induction of CD44, BMI-1, Oct-4, NANOG, CXCR4, and SDF-1. Activation of EGFR also resulted in increased tumorsphere formation, a characteristic ability of cancer stem cells. Conversely, treatment with the EGFR kinase inhibitor, Gefinitib (Iressa), resulted in decreased expression of the aforementioned genes, and loss of tumorsphere-forming ability. Similar trends were observed in a 99.9% CD44 positive stem cell culture derived from a fresh HNSCC tumor, confirming our findings for the cell lines. Additionally, we found that these putative cancer stem cells, when treated with Gefitinib, possessed a lower capacity to invade and became more sensitive to cisplatin-induced death in vitro. These results suggest that EGFR plays critical roles in the survival, maintenance, and function of cancer stem cells. Drugs that target EGFR, perhaps administered in combination with conventional chemotherapy, might be an effective treatment for HNSCC
- …