CMT1A current gene therapy approaches and promising biomarkers

Charcot-Marie-Tooth neuropathies(CMT)constitute a group of common but highly heterogeneous,non-syndromic genetic disorders affecting predominantly the peripheral nervous system.CMT type 1A(CMT1A)is the most frequent type and accounts for almost~50%of all diagnosed CMT cases.CMT1A results from the duplication of the peripheral myelin protein 22(PMP22)gene.Overexpression of PMP22 protein overloads the protein folding apparatus in Schwann cells and activates the unfolded protein response.This leads to Schwann cell apoptosis,dys-and de-myelination and secondary axonal degeneration,ultimately causing neurological disabilities.During the last decades,several different gene therapies have been developed to treat CMT1A.Almost all of them remain at the pre-clinical stage using CMT1A animal models overexpressing PMP22.The therapeutic goal is to achieve gene silencing,directly or indirectly,thereby reversing the CMT1A genetic mechanism allowing the recovery of myelination and prevention of axonal loss.As promising treatments are rapidly emerging,treatment-responsive and clinically relevant biomarkers are becoming necessary.These biomarkers and sensitive clinical evaluation tools will facilitate the design and successful completion of future clinical trials for CMT1A.

Restless legs syndrome is contributing to fatigue and low quality of life levels in hemodialysis patients

AIM To examine whether hemodialysis(HD) patients with restless legs syndrome(RLS) are subjects of greater fatigue and impaired quality of life(QoL) compared to HD patients without RLS.METHODS Eighty five stable HD patients participated in this study. According to their RLS status, the patients were dividedinto the RLS group(n = 23) and the non-RLS group(n = 62). QoL, fatigue, sleep quality, daily sleepiness and depression symptoms were assessed by using various questionnaires. Finally, biochemical parameters including iron, ferritin, hemoglobin, hematocrit and parathormone were assessed. RESULTS The HD patients with RLS scored worse in all the questionnaires used in the study(P < 0.05). The patients with RLS were more likely to receive the HD therapy on the morning shift, whilst 43.5% of the RLS patients reported to experience the RLS symptoms also during HD. The severity of RLS was correlated with fatigue, depression score and sleep quality(P < 0.05). CONCLUSION HD patients with RLS are subject to lower QoL related parameters and greater fatigue compared to HD patients without RLS. RLS should be successfully managed in order to improve the QoL of the sufferers.

Molecular diagnosis of autosomal recessive cerebellar ataxia in the whole exome/genome sequencing era

Autosomal recessive cerebellar ataxias(ARCA) are a clinically and genetically heterogeneous group of rare neurodegenerative disorders characterized by autosomal recessive inheritance and an early age of onset. Progressive ataxia is usually the prominent symptom and is often associated with other neurological or additional features. ARCA classification still remains controversial even though different approaches have been proposed over the years. Furthermore, ARCA molecular diagnosis has been a challenge due to phenotypic overlap and increased genetic heterogeneity observed within this group of disorders. Friedreich's ataxia and ataxia telangiectasia have been reported as the most frequent and well-studied forms of ARCA. Significant progress in understanding the genetic etiologies of the ARCA has been achieved during the last 15 years. The methodological revolution that has been observed in genetics over the last few years has contributed significantly to the molecular diagnosis of rare diseases including the ARCAs. Development of high throughput technologies has resulted in the identification of new ARCA genes and novel mutations in known ARCA genes. Therefore,an improvement in the molecular diagnosis of ARCA is expected. Moreover, based on the fact that many patients still remain undiagnosed, additional forms of ataxia are expected to be identified. We hereby review the current knowledge on the ARCAs, focused on the genetic findings of the most common forms that were molecularly characterized before the whole exome/genome era, as well as the most recently described forms that have been elucidated with the use of these novel technologies. The significant contribution of wholeexome sequencing or whole-genome sequencing in the molecular diagnosis of ARCAs is discussed.

Comparison of next generation sequencing-based and methylated DNA immunoprecipitation-based approaches for fetal aneuploidy non-invasive prenatal testing

Over the past few years, many researchers have attempted to develop non-invasive prenatal testing methods in order to investigate the genetic status of the fetus. The aim is to avoid invasive procedures such as chorionic villus and amniotic fluid sampling, which result in a significant risk for pregnancy loss. The discovery of cell free fetal DNA circulating in the maternal blood has great potential for the development of non-invasive prenatal testing(NIPT) methodologies. Such strategies have been successfully applied for the determination of the fetal rhesus status and inherited monogenic disease but the field of fetal aneuploidy investigation seems to be more challenging. The main reason for this is that the maternal cell free DNA in the mother's plasma is far more abundant, and because it is identical to half of the corresponding fetal DNA. Approaches developed are mainly based on next generation sequencing(NGS) technologies and epigenetic genetic modifications, such as fetal-maternal DNA differential methylation. At present, genetic services for non-invasive fetal aneuploidy detection are offered using NGS-based approaches but, for reasons that are presented herein, they still serve as screening tests which are not readily accessed by the majority of couples. Here we discuss the limitations of both strategies for NIPT and the future potential of the methods developed.

Thermal activation of Ti_((1-x))Au_((x))thin films with enhanced hardness and biocompatibility

The lifetime of orthopaedic implants can be extended by coating the softer Ti6Al4V alloy with harder biocompatible thin films.In this work,thin films of Ti_((1-x))Au_((x))are grown on Ti_(6)Al_(4)V and glass substrates by magnetron sputtering in the entire x=0-1 range,before their key biomechanical properties are performance tuned by thermal activation.For the first time,we explore the effect of in-situ substrate heating versus ex-situ post-deposition heat-treatment,on development of mechanical and biocompatibility performance in Ti-Au films.A~250% increase in hardness is achieved for Ti-Au films compared to bulk Ti6Al4V and a~40%improvement from 8.8 GPa as-grown to 11.9 and 12.3 GPa with in-situ and ex-situ heat-treatment respectively,is corelated to changes in structural,morphological and chemical properties,providing insights into the origins of super-hardness in the Ti rich regions of these materials.X-ray diffraction reveals that as-grown films are in nanocrystalline states of Ti-Au intermetallic phases and thermal activation leads to emergence of mechanically hard Ti-Au intermetallics,with films prepared by in-situ substrate heating having enhanced crystalline quality.Surface morphology images show clear changes in grain size,shape and surface roughness following thermal activation,while elemental analysis reveals that in-situ substrate heating is better for development of oxide free Ti3Auβ-phases.All tested Ti-Au films are non-cytotoxic against L929 mouse fibroblast cells,while extremely low leached ion concentrations confirm their biocompatibility.With peak hardness performance tuned to>12 GPa and excellent biocompatibility,Ti-Au films have potential as a future coating technology for load bearing medical implants.