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Amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD), 2 incurable neurodegenerative disorders, share the same pathological hallmark named TDP43 (TAR DNA binding protein 43) proteinopathy. This event is characterized by a consistent cytoplasmic mislocalization and aggregation of the protein TDP43, which loses its physiological properties, leading neurons to death. Antibody-based approaches are now emerging interventions in the field of neurodegenerative disorders. Here, we tested the target specificity, in vivo distribution, and therapeutic efficacy of a monoclonal full-length antibody, named E6, in TDP43-related conditions. We observed that the antibody recognizes specifically the cytoplasmic fraction of TDP43. We demonstrated its ability in targeting large neurons in the spinal cord of mice and in reducing TDP43 mislocalization and NF-κB activation. We also recognized the proteasome as well as the lysosome machineries as possible mechanisms used by the antibody to reduce TDP43 proteinopathy. To our knowledge, this is the first report showing the therapeutic efficacy and feasibility of a full-length antibody against TDP43 in reducing TDP43 proteinopathy in spinal neurons of an ALS/FTLD mouse model.

To investigate the role of neuronal NF-κB activity in pathogenesis of amyotrophic lateral sclerosis (ALS), we generated transgenic mice with neuron-specific expression of a super-repressor form of the NF-κB inhibitor (IκBα-SR), which were then crossed with mice of both sexes, expressing ALS-linked gene mutants for TAR DNA-binding protein (TDP-43) and superoxide dismutase 1 (SOD1). Remarkably, neuronal expression of IκBα-SR transgene in mice expressing TDP-43 A315T or TDP-43 G348C mice led to a decrease in cytoplasmic to nuclear ratio of human TDP-43. The mitigation of TDP-43 neuropathology by IκBα-SR, which is likely due to an induction of autophagy, was associated with amelioration of cognitive and motor deficits as well as reduction of motor neuron loss and gliosis. Neuronal suppression of NF-κB activity in SOD1 G93A mice also resulted in neuroprotection with reduction of misfolded SOD1 levels and significant extension of life span. The results suggest that neuronal NF-κB signaling constitutes a novel therapeutic target for ALS disease and related disorders with TDP-43 proteinopathy. SIGNIFICANCE STATEMENT This study reports that neuron-specific expression of IκB super-repressor mitigated behavioral and pathologic changes in transgenic mouse models of amyotrophic lateral sclerosis expressing mutant forms of either Tar DNA-binding protein 43 or superoxide dismutase. The results suggest that neuronal NF-κB signaling constitutes a novel therapeutic target for amyotrophic lateral sclerosis and related disorders with Tar DNA-binding protein 43 proteinopathy., (Copyright © 2020 Dutta et al.)

To test the hypothesis that the cerebrospinal fluid (CSF) could provide a spreading route for pathogenesis of amyotrophic lateral sclerosis (ALS), we have examined the effects of intraventricular infusion during 2 weeks of pooled CSF samples from sporadic ALS patients or control CSF samples into transgenic mice expressing human TDP43 WT which do not develop pathological phenotypes. Infusion of ALS-CSF, but not of control CSF, triggered motor and cognitive dysfunction, as well as ALS-like pathological changes including TDP43 proteinopathy, neurofilament disorganization and neuroinflammation. In addition, the neuron-specific translational profiles from peptide analyses of immunoprecipitated ribosomes revealed dysregulation of multiple protein networks in response to ALS-CSF altering cytoskeletal organization, vesicle trafficking, mitochondrial function, and cell metabolism. With normal mice, similar ALS-CSF infusion induced mild motor dysfunction but without significant TDP43 pathology in spinal neurons. We conclude that the CSF from sporadic ALS contains factors that can transmit and disseminate disease including TDP43 proteinopathy into appropriate recipient animal model expressing human TDP43. These findings open new research avenues for the discovery of etiogenic factors for sporadic ALS and for the testing of drugs aiming to neutralize the ALS-CSF toxicity.

Background: Despite the increasing use of medical records to measure quality of care, studies have shown that their validity is suboptimal. The objective of this study is to assess the concordance of cardiovascular care processes evaluated through medical record review and patient self-administered questionnaires (SAQs) using ten quality indicators (TRANSIT indicators). These indicators were developed as part of a participatory research program (TRANSIT study) dedicated to TRANSforming InTerprofessional clinical practices to improve cardiovascular disease (CVD) prevention in primary care., Methods: For every patient participating in the TRANSIT study, the compliance to each indicator (individual scores) as well as the mean compliance to all indicators of a category (subscale scores) and to the complete set of ten indicators (overall scale score) were established. Concordance between results obtained using medical records and patient SAQs was assessed by prevalence-adjusted bias-adjusted kappa (PABAK) coefficients as well as intraclass correlation coefficients (ICCs) and 95% confidence intervals (95% CI). Generalized linear mixed models (GLMM) were used to identify patients' sociodemographic and clinical characteristics associated with agreement between the two data sources., Results: The TRANSIT study was conducted in a primary care setting among patients (n = 759) with multimorbidity, at moderate (16%) and high risk (83%) of cardiovascular diseases. Quality of care, as measured by the TRANSIT indicators, varied substantially between medical records and patient SAQ. Concordance between the two data sources, as measured by ICCs (95% CI), was poor for the subscale (0.18 [0.08-0.27] to 0.46 [0.40-0.52]) and overall (0.46 [0.40-0.53]) compliance scale scores. GLMM showed that agreement was not affected by patients' characteristics., Conclusions: In quality improvement strategies, researchers must acknowledge that care processes may not be consistently recorded in medical records. They must also be aware that the evaluation of the quality of care may vary depending on the source of information, the clinician responsible of documenting the interventions, and the domain of care.

The cytoplasmic aggregation of TAR DNA-binding protein-43 (TDP-43) is a hallmark of degenerating neurons in amyotrophic lateral sclerosis (ALS) and subsets of frontotemporal dementia (FTD). In order to reduce TDP-43 pathology, we generated single-chain (scFv) antibodies against the RNA recognition motif 1 (RRM1) of TDP-43, which is involved in abnormal protein self-aggregation and interaction with p65 NF-κB. Virus-mediated delivery into the nervous system of a scFv antibody, named VH7Vk9, reduced microgliosis in a mouse model of acute neuroinflammation and mitigated cognitive impairment, motor defects, TDP-43 proteinopathy, and neuroinflammation in transgenic mice expressing ALS-linked TDP-43 mutations. These results suggest that antibodies targeting the RRM1 domain of TDP-43 might provide new therapeutic avenues for the treatment of ALS and FTD.

Objective: To assess a selection of psychometric properties of the TRANSIT indicators., Design: Using medical records, indicators were documented retrospectively during the 14 months preceding the end of the TRANSIT study., Setting: Primary care in Quebec, Canada., Participants: Indicators were documented in a random subsample (n = 123 patients) of the TRANSIT study population (n = 759)., Interventions: For every patient, the mean compliance to all indicators of a category (subscale score) and to the complete set of indicators (overall scale score) were established. To evaluate test-retest and inter-rater reliabilities, indicators were applied twice, two months apart, by the same evaluator and independently by different evaluators, respectively. To evaluate convergent validity, correlations between TRANSIT indicators, Burge et al. indicators and Institut national d'excellence en santé et en services sociaux (INESSS) indicators were examined., Main Outcome Measures: Test-retest reliability, inter-rater reliability, and convergent validity., Results: Test-retest reliability, as measured by intraclass correlation coefficients (ICCs) was equal to 0.99 (0.99-0.99) for the overall scale score while inter-rater reliability was equal to 0.95 (0.93-0.97) for the overall scale score. Convergent validity, as measured by Pearson's correlation coefficients, was equal to 0.77 (P < 0.001) for the overall scale score when the TRANSIT indicators were compared to Burge et al. indicators and to 0.82 (P < 0.001) for the overall scale score when the TRANSIT indicators were compared to INESSS indicators., Conclusions: Reliability was excellent except for eleven indicators while convergent validity was strong except for domains related to the management of CVD risk factors., (© The Author 2017. Published by Oxford University Press in association with the International Society for Quality in Health Care. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com)

Cytoplasmic TDP-43 aggregation is a pathological hallmark of amyotrophic lateral sclerosis and frontotemporal lobar degeneration. Here we investigated the role of exosomes in the secretion and propagation of TDP-43 aggregates. TDP-43 was detected in secreted exosomes from Neuro2a cells and primary neurons but not from astrocytes or microglia. Evidence is presented that protein aggregation and autophagy inhibition are factors that promote exosomal secretion of TDP-43. We also report that levels of exosomal TDP-43 full length and C-terminal fragment species are upregulated in human amyotrophic lateral sclerosis brains. Exposure of Neuro2a cells to exosomes from amyotrophic lateral sclerosis brain, but not from control brain, caused cytoplasmic redistribution of TDP-43, suggesting that secreted exosomes might contribute to propagation of TDP-43 proteinopathy. Yet, inhibition of exosome secretion by inactivation of neutral sphingomyelinase 2 with GW4869 or by silencing RAB27A provoked formation of TDP-43 aggregates in Neuro2a cells. Moreover, administration of GW4869 exacerbated the disease phenotypes of transgenic mice expressing human TDP-43 A315T mutant. Thus, even though results suggest that exosomes containing pathological TDP-43 may play a key role in the propagation of TDP-43 proteinopathy, a therapeutic strategy for amyotrophic lateral sclerosis based on inhibition of exosome production would seem inappropriate, as in vivo data suggest that exosome secretion plays an overall beneficial role in neuronal clearance of pathological TDP-43., (© The Author (2016). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Background: Facilitation is a powerful approach to support practice change. The purpose of this study is to better understand the facilitation roles exercised by both external facilitators and interprofessional facilitation teams to foster the implementation of change. Building on Dogherty et al.'s taxonomy of facilitation activities, this study uses an organizational development lens to identify and analyze facilitation roles. It includes a concise definition of what interprofessional facilitation teams actually do, thus expanding our limited knowledge of teams that act as change agents. We also investigate the facilitation dynamics between change actors., Methods: We carried out a qualitative analysis of a 1-year process of practice change implementation. We studied four family medicine groups, in which we constituted interprofessional facilitation teams. Each team was supported by one external facilitator and included at least one family physician, one case manager nurse, and health professionals located on or off the family medicine group's site (one pharmacist, plus at least one nutritionist, kinesiologist, or psychologist). We collected our data through focus group interviews with the four teams, individual interviews with the two external facilitators, and case audit documentation. We analyzed both predetermined (as per Dogherty et al., 2012) and emerging facilitation roles, as well as facilitation dynamics., Results: A non-linear framework of facilitation roles emerged from our data, based on four fields of expertise: change management, project management, meeting management, and group/interpersonal dynamics. We identified 72 facilitation roles, grouped into two categories: "implementation-oriented" and "support-oriented." Each category was subdivided into themes (n = 6; n = 5) for clearer understanding (e.g., legitimation of change/project, management of effective meetings). Finally, an examination of facilitation dynamics revealed eight relational ties occurring within and/or between groups of actors., Conclusions: Facilitation is an approach used by appointed individuals, which teams can also foster, to build capacity and support practice change. Increased understanding of facilitation roles constitutes an asset in training practitioners such as organizational development experts, consultants, facilitators, and facilitation teams. It also helps decision makers become aware of the multiple roles and dynamics involved and the key competencies needed to recruit facilitators and members of interprofessional facilitation teams.

Background: Seven chronic disease prevention and management programs were implemented across Quebec with funding support from a provincial-private industry funding initiative. Given the complexity of implementing integrated primary care chronic disease management programs, a knowledge transfer meeting was held to share experiences across programs and synthesize common challenges and success factors for implementation., Methods: The knowledge translation meeting was held in February 2014 in Montreal, Canada. Seventy-five participants consisting of 15 clinicians, 14 researchers, 31 knowledge users, and 15 representatives from the funding agencies were broken up into groups of 10 or 11 and conducted a strengths, weaknesses, opportunities, and threats analysis on either the implementation or the evaluation of these chronic disease management programs. Results were reported back to the larger group during a plenary and recorded. Audiotapes were transcribed and summarized using pragmatic thematic analysis., Results and Discussion: Strengths to leverage for the implementation of the seven programs include: (1) synergy between clinical and research teams; (2) stakeholders working together; (3) motivation of clinicians; and (4) the fact that the programs are evidence-based. Weaknesses to address include: (1) insufficient resources; (2) organizational change within the clinical sites; (3) lack of referrals from primary care physicians; and (4) lack of access to programs. Strengths to leverage for the evaluation of these programs include: (1) engagement of stakeholders and (2) sharing of knowledge between clinical sites. Weaknesses to address include: (1) lack of referrals; (2) difficulties with data collection; and (3) difficulties in identifying indicators and control groups. Opportunities for both themes include: (1) fostering new and existing partnerships and stakeholder relations; (2) seizing funding opportunities; (3) knowledge transfer; (4) supporting the transformation of professional roles; (5) expand the use of health information technology; and (6) conduct cost evaluations. Fifteen recommendations related to mobilisation of primary care physicians, support for the transformation of professional roles, and strategies aimed at facilitating the implementation and evaluation of chronic disease management programs were formulated based on the discussions at this knowledge translation event., Conclusion: The results from this knowledge translation day will help inform the sustainability of these seven chronic disease management programs in Quebec and the implementation and evaluation of similar programs elsewhere.

There is emerging evidence that the misfolding of superoxide dismutase 1 (SOD1) may represent a common pathogenic event in both familial and sporadic amyotrophic lateral sclerosis (ALS). To reduce the burden of misfolded SOD1 species in the nervous system, we have tested a novel therapeutic approach based on adeno-associated virus (AAV)-mediated tonic expression of a DNA construct encoding a secretable single-chain fragment variable (scFv) antibody composed of the variable heavy and light chain regions of a monoclonal antibody (D3H5) binding specifically to misfolded SOD1. A single intrathecal injection of the AAV encoding the single-chain antibody in SOD1(G93A) mice at 45 days of age resulted in sustained expression of single-chain antibodies in the spinal cord, and it delayed disease onset and extension of life span by up to 28%, in direct correlation with scFv titers in the spinal cord. The treatment caused attenuation of neuronal stress signals and reduction in levels of misfolded SOD1 in the spinal cord of SOD1(G93A) mice. From these results, we propose that an immunotherapy based on intrathecal inoculation of AAV encoding a secretable scFv against misfolded SOD1 should be considered as potential treatment for ALS, especially for individuals carrying SOD1 mutations.

Background: The chronic care model provides a framework for improving the management of chronic diseases. Participatory research could be useful in developing a chronic care model-based program of interventions, but no one has as yet offered a description of precisely how to apply the approach., Objectives: An innovative, structured, multi-step participatory process was applied to select and develop (1) chronic care model-based interventions program to improve cardiovascular disease prevention that can be adapted to a particular regional context and (2) a set of indicators to monitor its implementation., Methods: Primary care clinicians (n = 16), administrative staff (n = 2), patients and family members (n = 4), decision makers (n = 5), researchers, and a research coordinator (n = 7) took part in the process. Additional primary care actors (n = 26) validated the program., Results: The program targets multimorbid patients at high or moderate risk of cardiovascular disease with uncontrolled hypertension, dyslipidemia or diabetes. It comprises interprofessional follow-up coordinated by case-management nurses, in which motivated patients are referred in a timely fashion to appropriate clinical and community resources. The program is supported by clinical tools and includes training in motivational interviewing. A set of 89 process and clinical indicators were defined., Conclusion: Through a participatory process, a contextualized interventions program to optimize cardiovascular disease prevention and a set of quality indicators to monitor its implementation were developed. Similar approach might be used to develop other health programs in primary care if program developers are open to building on community strengths and priorities.

Transactive response DNA-binding protein 43 ubiquitinated inclusions are a hallmark of amyotrophic lateral sclerosis and of frontotemporal lobar degeneration with ubiquitin-positive inclusions. Yet, mutations in TARDBP, the gene encoding these inclusions are associated with only 3% of sporadic and familial amyotrophic lateral sclerosis. Recent transgenic mouse studies have revealed a high degree of toxicity due to transactive response DNA-binding protein 43 proteins when overexpressed under the control of strong neuronal gene promoters, resulting in early paralysis and death, but without the presence of amyotrophic lateral sclerosis-like ubiquitinated transactive response DNA-binding protein 43-positive inclusions. To better mimic human amyotrophic lateral sclerosis, we generated transgenic mice that exhibit moderate and ubiquitous expression of transactive response DNA-binding protein 43 species using genomic fragments that encode wild-type human transactive response DNA-binding protein 43 or familial amyotrophic lateral sclerosis-linked mutant transactive response DNA-binding protein 43 (G348C) and (A315T). These novel transgenic mice develop many age-related pathological and biochemical changes reminiscent of human amyotrophic lateral sclerosis including ubiquitinated transactive response DNA-binding protein 43-positive inclusions, transactive response DNA-binding protein 43 cleavage fragments, intermediate filament abnormalities, axonopathy and neuroinflammation. All three transgenic mouse models (wild-type, G348C and A315T) exhibited impaired learning and memory capabilities during ageing, as well as motor dysfunction. Real-time imaging with the use of biophotonic transactive response DNA-binding protein 43 transgenic mice carrying a glial fibrillary acidic protein-luciferase reporter revealed that the behavioural defects were preceded by induction of astrogliosis, a finding consistent with a role for reactive astrocytes in amyotrophic lateral sclerosis pathogenesis. These novel transactive response DNA-binding protein 43 transgenic mice mimic several characteristics of human amyotrophic lateral sclerosis-frontotemporal lobar degeneration and they should provide valuable animal models for testing therapeutic approaches.

Molecular pathophysiology of facioscapulohumeral muscular dystrophy (FSHD) involves the heterozygous contraction of the number of tandemly repeated D4Z4 units at chromosome 4q35.2. FSHD is associated with a range of 1-10 D4Z4 units instead of 11-150 in normal controls. Several factors complicate FSHD molecular diagnosis, especially the cis-segregation of D4Z4 contraction with a 4qA allele, whereas D4Z4 shortening is silent both on alleles 4qB and 10q. Discrimination of pathogenic 4q-D4Z4 alleles from highly homologous 10q-D4Z4 arrays requires the use of the conventional Southern blot, which is not suitable at the single-cell level. Preimplantation genetic diagnosis (PGD) is a frequent request from FSHD families with several affected relatives. We aimed to develop a rapid and sensitive PCR-based multiplex approach on single cells to perform an indirect familial segregation study of pathogenic alleles. Among several available polymorphic markers at 4q35.2, the four most proximal (D4S2390, D4S1652, D4S2930 and D4S1523, <1.23 Mb) showing the highest heterozygote frequencies (67-91%) were selected. Five recombination events in the D4S2390-D4S1523 interval were observed among 144 meioses. In the D4S2390-D4Z4 interval, no recombination event occurred among 28 FSHD meioses. Instead, a particular haplotype segregated with both clinical and molecular status, allowing the characterization of an at-risk allele in each tested FSHD family (maximal LOD score 2.98 for theta=0.0). This indirect protocol can easily complement conventional techniques in prenatal diagnosis. Although our multiplex PCR-based approach technically fulfils guidelines for single-cell analysis, the relatively high recombination risk hampers its application to PGD.

Available commercial kits only screen for the most common cystic fibrosis transmembrane conductance regulator (CFTR) mutations causing classic cystic fibrosis and for the Tn variant in IVS8. However, full scanning of CFTR is needed for the diagnosis of patients with cystic fibrosis or CFTR-related disorders (including congenital bilateral absence of the vas deferens) bearing rare mutations. Standard strategies for detecting point mutations rely on extensive scanning of the gene by denaturing gradient gel electrophoresis or denaturing high performance liquid chromatography, which are time-consuming. Moreover, the haplotyping of IVS8-(TG)m and Tn tracts is still challenging despite several recent improvements. We have optimized both the detection of mutations and the haplotyping of IVS8 polyvariants in developing two methods: i) a rapid and robust direct sequence analysis of all exons/flanking introns of the CFTR gene based on single condition touchdown amplification/sequencing in 96-well plates, and ii) a fluorescent assay that allows haplotyping of IVS8-(TG)mTn even without family linkage study. Combined with search for rare large rearrangements, this strategy detected 87.9% of CFTR defects in congenital bilateral absence of the vas deferens patients, a proportion considerably higher than those usually reported. These highly efficient tests, scanning each sample in a few days, greatly improve the genotyping of patients with CFTR-related symptoms and may be particularly important in emergency situations such as fetus with hyperechogenic bowel suggestive of cystic fibrosis.

DNA microarray technology enables investigators to measure the expression of several 1000 mRNA species simultaneously in a biological specimen. However, the reliability of the microarray technology to detect transcriptional differences representative of the original samples is affected by the quality of the extracted RNA. Thus, it is of critical importance to standardize sample-handling protocols and to perform a quality assessment of RNA preparations. In this report, 59 human tissue samples were used to evaluate the relationships between RNA quality and gene expression. From Affymetrix GeneChip array data analysis of these samples, we compared the performance of the 28S/18S ratio, two computer methods (RIN and degradometer) and our in-house RNA quality scale (RQS) in assessing RNA quality. The optimal RNA reliability threshold was determined for each method using statistical discrimination measures. We showed that RQS, RIN and degradometer have a similar capacity to detect reliable RNA samples whereas the 28S/18S ratio leads to a misleading categorization. Furthermore, we developed a new approach, based on clustering analyses of full chip expression, to control RNA quality after hybridization experiments. The combination of these methods, allowing monitoring of RNA quality prior to and after the hybridization experiments, ensured reliable and reproducible microarray data.

Retinitis pigmentosa (RP) is a clinically and genetically heterogeneous group of retinal diseases leading to blindness. By performing full genome linkage analysis in a consanguineous French family affected with severe autosomal recessive RP, we have excluded linkage to known loci involved in RP and mapped a novel locus to chromosome 16q13-q21 (Zmax=2.83 at theta=0 at the D16S3089 locus). Two candidate genes KIFC3 and CNGB1 mapping to this critical interval have been screened for mutations. The CNGB1 gene, which encodes the beta-subunit of the rod cGMP-gated channel, is mutated in the family presented in this study.

Autosomal recessive Charcot-Marie-Tooth disease (CMT) type 4 (CMT4) is a complex group of demyelinating hereditary motor and sensory neuropathies presenting genetic heterogeneity. Five different subtypes that correspond to six different chromosomal locations have been described. We hereby report a large inbred Lebanese family affected with autosomal recessive CMT4, in whom we have excluded linkage to the already-known loci. The results of a genomewide search demonstrated linkage to a locus on chromosome 19q13.1-13.3, over an 8.5-cM interval between markers D19S220 and D19S412. A maximum pairwise LOD score of 5.37 for marker D19S420, at recombination fraction [theta].00, and a multipoint LOD score of 10.3 for marker D19S881, at straight theta = .00, strongly supported linkage to this locus. Clinical features and the results of histopathologic studies confirm that the disease affecting this family constitutes a previously unknown demyelinating autosomal recessive CMT subtype known as "CMT4F." The myelin-associated glycoprotein (MAG) gene, located on 19q13.1 and specifically expressed in the CNS and the peripheral nervous system, was ruled out as being the gene responsible for this form of CMT.

Retinal dystrophies are a complex set of hereditary diseases of the retina that result in the degeneration of photoreceptors. Recent studies have shown that mutations in RPE65, a gene that codes for a retinal pigment epithelium (RPE)-specific protein thought to be involved in the 11-cis-retinoid metabolism, a key process in vision, cause severe, early onset retinal dystrophy. We describe two novel missense RPE65 mutations, L22P and H68Y, in a compound heterozygote with autosomal recessive retinal dystrophy. The relatively mild phenotype associated with these mutations suggests a possible link between the severity of the disease and the type of mutations in the RPE65 gene.

Data from 6 years of experience in molecular diagnosis of Duchenne (DMD) and Becker (BMD) muscular dystrophy in Southern France are reported. DMD and BMD patients have been extensively analyzed for deletions and for point mutations in the dystrophin gene. By scanning the whole coding sequence as reverse-transcribed from lymphocytes or muscular RNA by the protein truncation test, we have reached a minimum of an 86% detection rate for point mutations responsible for DMD; these mutations consist of nonsense, frameshifting, and splicing mutations. Four of 12 small alterations identified in our sample are novel and described in this study. We also present an improved protocol for the automated detection of fluorescently labeled duplex polymerase chain reactions of six known intragenic microsatellites (Dys II, TG 15, STRs 44, 45, 49, and 50). Accurate sizing of the alleles at each locus was performed, and we elucidated the sequence of several repeat units. Allele frequencies at each of the six microsatellite loci and at one restriction fragment length polymorphism site (intron 16/TaqI) were defined in a sample of normal, DMD, and BMD X chromosomes from Southern France. The determination of the grandparental origin of either deletions or point mutations revealed differences depending on the type of the mutation, with most of the deletions occurring in oogenesis and most of the point mutations occurring in spermatogenesis.

About 30% of cases of Duchenne muscular dystrophy (DMD) result from point mutations randomly distributed in the immense dystrophin gene. As already observed for the gross rearrangements, most of the DMD point mutations identified so far give rise to truncated proteins. Here, we report results of a comprehensive search for point mutations within the dystrophin gene based on illegitimate transcript analysis by using the RT-PCR technique in combination with a method capable of selectively detecting translation-termination mutations, called the protein truncation test (PTT). The RT-PCR-PTT procedure was successful in detecting mutations in 4 out of the 6 DMD patients who were investigated. These mutations, Q2972X in exon 59, 3474insC in exon 24, delT393-G394+5 in exon/intron 3, and 2436delAG in exon 18, had not been previously described. Moreover, several alternatively spliced forms of ectopic dystrophin mRNA were characterized in normal controls or in DMD patients. Most of these differentially spliced messages consisting of exon skipping or intronic sequence insertion are reported here for the first time.