Our findings expand the range of RYR1-related phenotypes and suggest RYR1 mutations as a common cause of congenital myopathies with central nuclei. Corresponding to recent observations in X-linked CNM, these findings indicate disturbed assembly and/or malfunction of the excitation-contraction machinery as a key mechanism in CNM and related myopathies.
Several small studies have reported that having a high percentage of breast tumor cells that express the proliferation antigen Ki-67 (ie, a high Ki-67 labeling index) predicts better response to neoadjuvant chemotherapy. However, the predictive value of a high Ki-67 labeling index for response to adjuvant chemotherapy is unclear. To investigate whether Ki-67 labeling index predicts response to adjuvant chemoendocrine therapy, we assessed Ki-67 expression in tumor tissue from 1924 (70%) of 2732 patients who were enrolled in two randomized International Breast Cancer Study Group trials of adjuvant chemoendocrine therapy vs endocrine therapy alone for node-negative breast cancer. A high Ki-67 labeling index was associated with other factors that predict poor prognosis. Among the 1521 patients with endocrine-responsive tumors, a high Ki-67 labeling index was associated with worse disease-free survival but the Ki-67 labeling index did not predict the relative efficacy of chemoendocrine therapy compared with endocrine therapy alone. Thus, Ki-67 labeling index was an independent prognostic factor but was not predictive of better response to adjuvant chemotherapy in these studies.
Congenital poikiloderma is characterized by a combination of mottled pigmentation, telangiectasia, and epidermal atrophy in the first few months of life. We have previously described a South African European-descent family affected by a rare autosomal-dominant form of hereditary fibrosing poikiloderma accompanied by tendon contracture, myopathy, and pulmonary fibrosis. Here, we report the identification of causative mutations in FAM111B by whole-exome sequencing. In total, three FAM111B missense mutations were identified in five kindreds of different ethnic backgrounds. The mutation segregated with the disease in one large pedigree, and mutations were de novo in two other pedigrees. All three mutations were absent from public databases and were not observed on Sanger sequencing of 388 ethnically matched control subjects. The three single-nucleotide mutations code for amino acid changes that are clustered within a putative trypsin-like cysteine/serine peptidase domain of FAM111B. These findings provide evidence of the involvement of FAM111B in congenital poikiloderma and multisystem fibrosis.
Low levels of ER and PgR are predictive of the benefit of adding chemotherapy to endocrine therapy. Low PgR may add further prediction among pre- and perimenopausal but not postmenopausal patients whose tumors express ER.
We conclude that a proportion of alveolar rhabdomyosarcomas (in particular) exhibit ALK protein expression. However, ALK expression is not restricted to this subtype. An extension of this study is to determine if this over-expression is as a result of the t(2;5) translocation.
Congenital myopathies are genetically and clinically heterogeneous conditions causing severe muscle weakness, and mutations in the ryanodine receptor gene (RYR1) represent the most frequent cause of these conditions. A common feature of diseases caused by recessive RYR1 mutations is a decrease of ryanodine receptor 1 protein content in muscle. The aim of the present investigation was to gain mechanistic insight into the causes of this reduced ryanodine receptor 1. We found that muscle biopsies of patients with recessive RYR1 mutations exhibit decreased expression of muscle-specific microRNAs, increased DNA methylation and increased expression of class II histone deacetylases. Transgenic mouse muscle fibres over-expressing HDAC-4/HDAC-5 exhibited decreased expression of RYR1 and of muscle-specific miRNAs, whereas acute knock-down of RYR1 in mouse muscle fibres by siRNA caused up-regulation of HDAC-4/HDAC-5. Intriguingly, increased class II HDAC expression and decreased ryanodine receptor protein and miRNAs expression were also observed in muscles of patients with nemaline myopathy, another congenital neuromuscular disorder. Our results indicate that a common pathophysiological pathway caused by epigenetic changes is activated in some forms of congenital neuromuscular disorders.
Members of two generations of a South African family have a unique syndrome comprising poikiloderma, tendon contractures and progressive pulmonary fibrosis. The condition is clinically important as the skin changes, which involve the face, have considerable cosmetic impact, while lung involvement is potentially lethal in adulthood. Skin manifestations which facilitate diagnosis include facial telangiectasia, mottled hypo- and hyperpigmentation, papules and epidermal atrophy. The scalp, facial and body hair are fine and scanty. The tendon contractures lead to progressive digital flexion deformities and abnormalities of the ankles and feet, with disturbance of gait. Pulmonary involvement manifests as progressive dyspnoea. Pedigree data are compatible with an autosomal dominant mode of transmission. Poikiloderma of Weary is characterized by linear sclerotic and fibrous bands and not tendon contractures and is not associated with potentially lethal pulmonary fibrosis. Rather than name this disorder a variant of Weary syndrome, it might be prudent to use as an umbrella title one composed by Weary himself: 'hereditary sclerosing poikiloderma' (HSP), under which variants such as HSP Weary type, HSP with cardiac involvement (aortic stenosis described as inconsistently associated with Weary syndrome) and HSP with tendon/pulmonary involvement (current family) may be classified. The manifestations in this family differ from other poikilodermata and, to the best of our knowledge, have not been previously documented.
In skeletal muscle, excitation-contraction coupling is the process whereby the voltage-gated dihydropyridine receptor (DHPR) located on the transverse tubules activates calcium release from the sarcoplasmic reticulum by activating ryanodine receptor (RyR1) Ca 2+ channels located on the terminal cisternae. This subcellular membrane specialization is necessary forproper intracellular signalling and any alterations in its architecture may lead to neuromuscular disorders. In this study we present evidence that patients with recessive RYR1-related congenital myopathies due to primary RyR1 deficiency also exhibit down-regulation of the alfa 1 subunit of the DHPR and show disruption of the spatial organization of the excitation-contraction coupling machinery. We created a cellular RyR1 knock-down model using immortalized human myoblasts transfected with RyR1 siRNA and confirm that knocking down RyR1 concomitantly down-regulates not only the DHPR but also the expression of other proteins involved in excitation-contraction coupling. Unexpectedly, this was paralleled by the up-regulation of inositol-1,4,5-triphosphate receptors; functionally however, up-regulation of the latter Ca 2+ channels did not compensate for the lack of RyR1-mediated Ca 2+ release. These results indicate that in some patients, RyR1 deficiency concomitantly alters the expression pattern of several proteins involved in calcium homeostasis and that this may influence the manifestation of these diseases.4
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.