Different Mouse Models of Nemaline Myopathy Harboring Acta1 Mutations Display Differing Abnormalities Related to Mitochondrial Biology.

ACTA1 encodes skeletal muscle-specific α-actin, which polymerizes to form the thin filament of the sarcomere. Mutations in ACTA1 are responsible for approximately 30% of nemaline myopathy (NM) cases. Previous studies of weakness in NM have focused on muscle structure and contractility, but genetic issues alone do not explain the phenotypic heterogeneity observed in patients with NM or NM mouse models. To identify additional biological processes related to NM phenotypic severity, proteomic analysis was performed using muscle protein isolates from wild-type mice in comparison to moderately affected knock-in (KI) Acta1H40Y and the minimally affected transgenic (Tg) ACTA1D286G NM mice. This analysis revealed abnormalities in mitochondrial function and stress-related pathways in both mouse models, supporting an in-depth assessment of mitochondrial biology. Interestingly, evaluating each model in comparison to its wild-type counterpart identified different degrees of mitochondrial abnormality that correlated well with the phenotypic severity of the mouse model. Muscle histology, mitochondrial respiration, electron transport chain function, and mitochondrial transmembrane potential were all normal or minimally affected in the TgACTA1D286G mouse model. In contrast, the more severely affected KI.Acta1H40Y mice displayed significant abnormalities in relation to muscle histology, mitochondrial respirometry, ATP, ADP, and phosphate content, and mitochondrial transmembrane potential. These findings suggest that abnormal energy metabolism is related to symptomatic severity in NM and may constitute a contributor to phenotypic variability and a novel treatment target.

Aberrations in Energetic Metabolism and Stress-Related Pathways Contribute to Pathophysiology in the Neb Conditional Knockout Mouse Model of Nemaline Myopathy.

Nemaline myopathy (NM) is a genetically and clinically heterogeneous disease that is diagnosed on the basis of the presence of nemaline rods on skeletal muscle biopsy. Although NM has typically been classified by causative genes, disease severity or prognosis cannot be predicted. The common pathologic end point of nemaline rods (despite diverse genetic causes) and an unexplained range of muscle weakness suggest that shared secondary processes contribute to the pathogenesis of NM. We speculated that these processes could be identified through a proteome-wide interrogation using a mouse model of severe NM in combination with pathway validation and structural/functional analyses. A proteomic analysis was performed using skeletal muscle tissue from the Neb conditional knockout mouse model compared with its wild-type counterpart to identify pathophysiologically relevant biological processes that might impact disease severity or provide new treatment targets. A differential expression analysis and Ingenuity Pathway Core Analysis predicted perturbations in several cellular processes, including mitochondrial dysfunction and changes in energetic metabolism and stress-related pathways. Subsequent structural and functional studies demonstrated abnormal mitochondrial distribution, decreased mitochondrial respiratory function, an increase in mitochondrial transmembrane potential, and extremely low ATP content in Neb conditional knockout muscles relative to wild type. Overall, the findings of these studies support a role for severe mitochondrial dysfunction as a novel contributor to muscle weakness in NM.

Proteomic analysis identifies key differences in the cardiac interactomes of dystrophin and micro-dystrophin.

ΔR4-R23/ΔCT micro-dystrophin (µDys) is a miniaturized version of dystrophin currently evaluated in a Duchenne muscular dystrophy (DMD) gene therapy trial to treat skeletal and cardiac muscle disease. In pre-clinical studies, µDys efficiently rescues cardiac histopathology, but only partially normalizes cardiac function. To gain insights into factors that may impact the cardiac therapeutic efficacy of µDys, we compared by mass spectrometry the composition of purified dystrophin and µDys protein complexes in the mouse heart. We report that compared to dystrophin, µDys has altered associations with α1- and ß2-syntrophins, as well as cavins, a group of caveolae-associated signaling proteins. In particular, we found that membrane localization of cavin-1 and cavin-4 in cardiomyocytes requires dystrophin and is profoundly disrupted in the heart of mdx5cv mice, a model of DMD. Following cardiac stress/damage, membrane-associated cavin-4 recruits the signaling molecule ERK to caveolae, which activates key cardio-protective responses. Evaluation of ERK signaling revealed a profound inhibition, below physiological baseline, in the mdx5cv mouse heart. Expression of µDys in mdx5cv mice prevented the development of cardiac histopathology but did not rescue membrane localization of cavins nor did it normalize ERK signaling. Our study provides the first comparative analysis of purified protein complexes assembled in vivo by full-length dystrophin and a therapeutic micro-dystrophin construct. This has revealed disruptions in cavins and ERK signaling that may contribute to DMD cardiomyopathy. This new knowledge is important for ongoing efforts to prevent and treat heart disease in DMD patients.

Cerebro-spinal fluid glucose and lactate concentrations changes in response to therapies in patIents with primary brain injury: the START-TRIP study.

INTRODUCTION: Altered levels of cerebrospinal fluid (CSF) glucose and lactate concentrations are associated with poor outcomes in acute brain injury patients. However, no data on changes in such metabolites consequently to therapeutic interventions are available. The aim of the study was to assess CSF glucose-to-lactate ratio (CGLR) changes related to therapies aimed at reducing intracranial pressure (ICP). METHODS: A multicentric prospective cohort study was conducted in 12 intensive care units (ICUs) from September 2017 to March 2022. Adult (> 18 years) patients admitted after an acute brain injury were included if an external ventricular drain (EVD) for intracranial pressure (ICP) monitoring was inserted within 24 h of admission. During the first 48-72 h from admission, CGLR was measured before and 2 h after any intervention aiming to reduce ICP ("intervention"). Patients with normal ICP were also sampled at the same time points and served as the "control" group. RESULTS: A total of 219 patients were included. In the intervention group (n = 115, 53%), ICP significantly decreased and CPP increased. After 2 h from the intervention, CGLR rose in both the intervention and control groups, although the magnitude was higher in the intervention than in the control group (20.2% vs 1.6%; p = 0.001). In a linear regression model adjusted for several confounders, therapies to manage ICP were independently associated with changes in CGLR. There was a weak inverse correlation between changes in ICP and CGRL in the intervention group. CONCLUSIONS: In this study, CGLR significantly changed over time, regardless of the study group. However, these effects were more significant in those patients receiving interventions to reduce ICP.

Evaluation of the dystrophin carboxy-terminal domain for micro-dystrophin gene therapy in cardiac and skeletal muscles in the DMDmdx rat model.

Duchenne muscular dystrophy (DMD) is a muscle wasting disorder caused by mutations in the gene encoding dystrophin. Gene therapy using micro-dystrophin (MD) transgenes and recombinant adeno-associated virus (rAAV) vectors hold great promise. To overcome the limited packaging capacity of rAAV vectors, most MD do not include dystrophin carboxy-terminal (CT) domain. Yet, the CT domain is known to recruit α1- and ß1-syntrophins and α-dystrobrevin, a part of the dystrophin-associated protein complex (DAPC), which is a signaling and structural mediator of muscle cells. In this study, we explored the impact of inclusion of the dystrophin CT domain on ΔR4-23/ΔCT MD (MD1), in DMDmdx rats, which allows for relevant evaluations at muscular and cardiac levels. We showed by LC-MS/MS that MD1 expression is sufficient to restore the interactions at a physiological level of most DAPC partners in skeletal and cardiac muscles, and that inclusion of the CT domain increases the recruitment of some DAPC partners at supra-physiological levels. In parallel, we demonstrated that inclusion of the CT domain does not improve MD1 therapeutic efficacy on DMD muscle and cardiac pathologies. Our work highlights new evidences of the therapeutic potential of MD1 and strengthens the relevance of this candidate for gene therapy of DMD.

Neuropsychological features in RASopathies: A pilot study on parent training program involving families of children with Noonan syndrome.

Noonan syndrome (NS) is a clinical variable multisystem disorder caused by mutations in genes encoding proteins involved in the RAS/mitogen-activated protein kinase signaling pathway. NS is characterized by a distinctive facies, short stature, and congenital heart defects. Psychomotor delay, learning difficulties, and social deficits are also common. Furthermore, behavioral and attention problems can be reckoned as a key symptom in NS, with functioning resembling the patterns observed in attention deficit hyperactivity disorder (ADHD). The complex behavioral phenotype has great impact on the quality of life and raises demanding management issues also for patients' families. Parent management training (PMT) is recommended as first-line treatment for ADHD; however, no study has been performed to test the efficacy of PMT in NS, thus far. The aim of this pilot study is the implementation and evaluation of a PMT dedicated to NS families. Parents of seven children with NS were recruited and underwent to a 10-session PMT. Three different questionnaires were administered to both parents: Conners Parent Rating Scales, Parenting Stress Index Short Form (PSI-SF), and Alabama Parenting Questionnaire (APQ). Our findings on this first small cohort of families indicate that positive perception and satisfaction about the child and the interaction with him increased in mothers after the intervention, as measured respectively by PSI-SF difficult child (DC) and PSI-SF parent-child dysfunctional interaction (PCDI), while mothers' level of stress decreased after the PMT, as indicated by PSI-SF total scores. Furthermore, APQ positive parenting, which measures behaviors of positive relationship with the child, increased in mothers after the intervention. Statistical analysis on fathers' questionnaires did not show significant differences after the PMT sessions. This pilot study suggests that PMT is a promising intervention for parents of NS children with behavioral and ADHD symptoms. Changes in mothers' attitudes and distress indicate that behaviorally oriented programs may help parents to manage with NS phenotype.

The ZZ domain of dystrophin in DMD: making sense of missense mutations.

Duchenne muscular dystrophy (DMD) is associated with the loss of dystrophin, which plays an important role in myofiber integrity via interactions with ß-dystroglycan and other members of the transmembrane dystrophin-associated protein complex. The ZZ domain, a cysteine-rich zinc-finger domain near the dystrophin C-terminus, is implicated in forming a stable interaction between dystrophin and ß-dystroglycan, but the mechanism of pathogenesis of ZZ missense mutations has remained unclear because not all such mutations have been shown to alter ß-dystroglycan binding in previous experimental systems. We engineered three ZZ mutations (p.Cys3313Phe, p.Asp3335His, and p.Cys3340Tyr) into a short construct similar to the Dp71 dystrophin isoform for in vitro and in vivo studies and delineated their effect on protein expression, folding properties, and binding partners. Our results demonstrate two distinct pathogenic mechanisms for ZZ missense mutations. The cysteine mutations result in diminished or absent subsarcolemmal expression because of protein instability, likely due to misfolding. In contrast, the aspartic acid mutation disrupts binding with ß-dystroglycan despite an almost normal expression at the membrane, confirming a role for the ZZ domain in ß-dystroglycan binding but surprisingly demonstrating that such binding is not required for subsarcolemmal localization of dystrophin, even in the absence of actin binding domains.

Fragile X Syndrome and FMR1 premutation: results from a survey on associated conditions and treatment priorities in Italy.

BACKGROUND AND OBJECTIVES: Fragile X Syndrome (FXS) is the most common cause of inherited intellectual disability, caused by CGG-repeat expansions (> 200) in the FMR1 gene leading to lack of expression. Espansion between 55 and 200 triplets fall within the premutation range (PM) and can lead to different clinical conditions, including fragile X- primary ovarian insufficiency (FXPOI), fragile X-associated neuropsychiatric disorders (FXAND) and fragile X-associated tremor/ataxia syndrome (FXTAS). Although there is not a current cure for FXS and for the Fragile X-PM associated conditions (FXPAC), timely diagnosis as well as the implementation of treatment strategies, psychoeducation and behavioral intervention may improve the quality of life (QoL) of people with FXS or FXPAC. With the aim to investigate the main areas of concerns and the priorities of treatment in these populations, the Italian National Fragile X Association in collaboration with Bambino Gesù Children's Hospital, conducted a survey among Italian participants. METHOD: Here, we present a survey based on the previous study that Weber and colleagues conducted in 2019 and that aimed to investigate the main symptoms and challenges in American individuals with FXS. The survey has been translated into Italian language to explore FXS needs of treatment also among Italian individuals affected by FXS, family members, caretakers, and professionals. Furthermore, we added a section designated only to people with PM, to investigate the main symptoms, daily living challenges and treatment priorities. RESULTS: Anxiety, challenging behaviors, language difficulties and learning disabilities were considered the major areas of concern in FXS, while PM was reported as strongly associated to cognitive problems, social anxiety, and overthinking. Anxiety was reported as a treatment priority in both FXS and PM. CONCLUSION: FXS and PM can be associated with a range of cognitive, affective, and physical health complications. Taking a patient-first perspective may help clinicians to better characterize the cognitive-behavioral phenotype associated to these conditions, and eventually to implement tailored therapeutic approaches.

Corrigendum: PTCHD1 gene mutation/deletion: the cognitive-behavioral phenotyping of four case reports.

[This corrects the article DOI: 10.3389/fpsyt.2023.1327802.].

Longitudinal follow-up of metformin treatment in Fragile X Syndrome.

Introduction: Metformin has been used as a targeted treatment to potentially improve cognition and slow the typical IQ decline that occurs during development among individuals with fragile X syndrome (FXS). In this follow-up study, we are following the trajectory of IQ and adaptive behavior changes over 1 to 3 years in individuals with FXS who are clinically treated with metformin in an open label trial. Method: Individuals with FXS ages 6 to 25 years (mean 13.15 ± 5.50) and nonverbal IQ mean 57.69 (±15.46) were treated for 1-3 years (1.88 ± 0.63). They all had a baseline IQ test using the Leiter-III non-verbal cognitive assessment and the Vineland-III adaptive behavior assessment before the start of metformin. Repeat Leiter-III and Vineland-III were completed after at least 1 year of metformin (500-1,000 mg/dose given twice a day). Result: There were no significant changes in non-verbal IQ or in the adaptive behavior measurements at FDR < 0.05. The findings thus far indicate that both IQ and adaptive behavior are stable over time, and we did not see a significant decline in either measure. Conclusion: Overall, the small sample size and short follow-up duration limit the interpretation of the effects of metformin on cognitive development and adaptive functioning. There is individual variability but overall for the group there was no significant decline in IQ or adaptive behavior.

"Corp-Osa-Mente", a Combined Psychosocial-Neuropsychological Intervention for Adolescents and Young Adults with Fragile X Syndrome: An Explorative Study.

Fragile X Syndrome is the most known inherited form of intellectual disability due to an expansion in the full mutation range (>200 CGG repeats) of the promoter region of the FMR1 gene located on X chromosomes leading to gene silencing. Despite clear knowledge of the cognitive-behavioral phenotype of FXS and the necessity of tailored interventions, empirical research on the effectiveness of behavioral treatments among patients with FXS is still lacking, with studies on adolescents and young adults even more insufficient. Here we present "Corposamente", a combined psychosocial-neuropsychological intervention conducted with a group of ten adolescents/young adults with FXS, who are non-ASD and without significant behavioral problems. In total, 20 sessions were performed, alternating between online and face-to-face meetings. At the end of the intervention, participants, family members and participants' educators anonymously completed a survey that was designed around key areas of improvement as well as treatment satisfaction. The survey results indicated that participants improved mostly in their ability to cope with negative emotions and that occupational intervention was considered the most effective technique both from families and participants. Our exploratory study suggests that group therapy for the management of the FXS cognitive-behavioral phenotype may be a promising approach to continue to pursue, mostly in adolescence when the environmental demands increase.

Investigating the Impact of Delivery Routes for Exon Skipping Therapies in the CNS of DMD Mouse Models.

Nucleic acid-based therapies have demonstrated great potential for the treatment of monogenetic diseases, including neurologic disorders. To date, regulatory approval has been received for a dozen antisense oligonucleotides (ASOs); however, these chemistries cannot readily cross the blood-brain barrier when administered systemically. Therefore, an investigation of their potential effects within the central nervous system (CNS) requires local delivery. Here, we studied the brain distribution and exon-skipping efficacy of two ASO chemistries, PMO and tcDNA, when delivered to the cerebrospinal fluid (CSF) of mice carrying a deletion in exon 52 of the dystrophin gene, a model of Duchenne muscular dystrophy (DMD). Following intracerebroventricular (ICV) delivery (unilateral, bilateral, bolus vs. slow rate, repeated via cannula or very slow via osmotic pumps), ASO levels were quantified across brain regions and exon 51 skipping was evaluated, revealing that tcDNA treatment invariably generates comparable or more skipping relative to that with PMO, even when the PMO was administered at higher doses. We also performed intra-cisterna magna (ICM) delivery as an alternative route for CSF delivery and found a biased distribution of the ASOs towards posterior brain regions, including the cerebellum, hindbrain, and the cervical part of the spinal cord. Finally, we combined both ICV and ICM injection methods to assess the potential of an additive effect of this methodology in inducing efficient exon skipping across different brain regions. Our results provide useful insights into the local delivery and associated efficacy of ASOs in the CNS in mouse models of DMD. These findings pave the way for further ASO-based therapy application to the CNS for neurological disease.

Networking to Optimize Dmd exon 53 Skipping in the Brain of mdx52 Mouse Model.

Duchenne muscular dystrophy (DMD) is caused by mutations in the DMD gene that disrupt the open reading frame and thus prevent production of functional dystrophin proteins. Recent advances in DMD treatment, notably exon skipping and AAV gene therapy, have achieved some success aimed at alleviating the symptoms related to progressive muscle damage. However, they do not address the brain comorbidities associated with DMD, which remains a critical aspect of the disease. The mdx52 mouse model recapitulates one of the most frequent genetic pathogenic variants associated with brain involvement in DMD. Deletion of exon 52 impedes expression of two brain dystrophins, Dp427 and Dp140, expressed from distinct promoters. Interestingly, this mutation is eligible for exon skipping strategies aimed at excluding exon 51 or 53 from dystrophin mRNA. We previously showed that exon 51 skipping can restore partial expression of internally deleted yet functional Dp427 in the brain following intracerebroventricular (ICV) injection of antisense oligonucleotides (ASO). This was associated with a partial improvement of anxiety traits, unconditioned fear response, and Pavlovian fear learning and memory in the mdx52 mouse model. In the present study, we investigated in the same mouse model the skipping of exon 53 in order to restore expression of both Dp427 and Dp140. However, in contrast to exon 51, we found that exon 53 skipping was particularly difficult in mdx52 mice and a combination of multiple ASOs had to be used simultaneously to reach substantial levels of exon 53 skipping, regardless of their chemistry (tcDNA, PMO, or 2'MOE). Following ICV injection of a combination of ASO sequences, we measured up to 25% of exon 53 skipping in the hippocampus of treated mdx52 mice, but this did not elicit significant protein restoration. These findings indicate that skipping mouse dystrophin exon 53 is challenging. As such, it has not yet been possible to answer the pertinent question whether rescuing both Dp427 and Dp140 in the brain is imperative to more optimal treatment of neurological aspects of dystrophinopathy.

PTCHD1 gene mutation/deletion: the cognitive-behavioral phenotyping of four case reports.

Introduction: X-linked PTCHD1 gene has recently been pointed as one of the most interesting candidates for involvement in neurodevelopmental disorders (NDs), such as intellectual disability (ID) and autism spectrum disorder (ASD). PTCHD1 encodes the patched domain-containing protein 1 (PTCHD1), which is mainly expressed in the developing brain and adult brain tissues. To date, major studies have focused on the biological function of the PTCHD1 gene, while the mechanisms underlying neuronal alterations and the cognitive-behavioral phenotype associated with mutations still remain unclear. Methods: With the aim of incorporating information on the clinical profile of affected individuals and enhancing the characterization of the genotype-phenotype correlation, in this study, we analyze the clinical features of four individuals (two children and two adults) in which array-CGH detected a PTCHD1 deletion or in which panel for screening non-syndromal XLID (X-linked ID) detected a PTCHD1 gene variant. We define the neuropsychological and psychopathological profiles, providing quantitative data from standardized evaluations. The assessment consisted of clinical observations, structured interviews, and parent/self-reported questionnaires. Results: Our descriptive analysis align with previous findings on the involvement of the PTCHD1 gene in NDs. Specifically, our patients exhibited a clinical phenotype characterized by psychomotor developmental delay- ID of varying severity. Interestingly, while ID during early childhood was associated with autistic-like symptomatology, this interrelation was no longer observed in the adult subjects. Furthermore, our cohort did not display peculiar dysmorphic features, congenital abnormalities or comorbidity with epilepsy. Discussion: Our analysis shows that the psychopathological and behavioral comorbidities along with cognitive impairment interfere with development, therefore contributing to the severity of disability associated with PTCHD1 gene mutation. Awareness of this profile by professionals and caregivers can promote prompt diagnosis as well as early cognitive and occupational enhancement interventions.

Cellular and molecular features of COVID-19 associated ARDS: therapeutic relevance.

The severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection can be asymptomatic or cause a disease (COVID-19) characterized by different levels of severity. The main cause of severe COVID-19 and death is represented by acute (or acute on chronic) respiratory failure and acute respiratory distress syndrome (ARDS), often requiring hospital admission and ventilator support.The molecular pathogenesis of COVID-19-related ARDS (by now termed c-ARDS) is still poorly understood. In this review we will discuss the genetic susceptibility to COVID-19, the pathogenesis and the local and systemic biomarkers correlated with c-ARDS and the therapeutic options that target the cell signalling pathways of c-ARDS.

Open-Label Sulforaphane Trial in FMR1 Premutation Carriers with Fragile-X-Associated Tremor and Ataxia Syndrome (FXTAS).

Fragile X (FMR1) premutation is a common mutation that affects about 1 in 200 females and 1 in 450 males and can lead to the development of fragile-X-associated tremor/ataxia syndrome (FXTAS). Although there is no targeted, proven treatment for FXTAS, research suggests that sulforaphane, an antioxidant present in cruciferous vegetables, can enhance mitochondrial function and maintain redox balance in the dermal fibroblasts of individuals with FXTAS, potentially leading to improved cognitive function. In a 24-week open-label trial involving 15 adults aged 60-88 with FXTAS, 11 participants successfully completed the study, demonstrating the safety and tolerability of sulforaphane. Clinical outcomes and biomarkers were measured to elucidate the effects of sulforaphane. While there were nominal improvements in multiple clinical measures, they were not significantly different after correction for multiple comparisons. PBMC energetic measures showed that the level of citrate synthase was higher after sulforaphane treatment, resulting in lower ATP production. The ratio of complex I to complex II showed positive correlations with the MoCA and BDS scores. Several mitochondrial biomarkers showed increased activity and quantity and were correlated with clinical improvements.

Insight and Recommendations for Fragile X-Premutation-Associated Conditions from the Fifth International Conference on FMR1 Premutation.

The premutation of the fragile X messenger ribonucleoprotein 1 (FMR1) gene is characterized by an expansion of the CGG trinucleotide repeats (55 to 200 CGGs) in the 5' untranslated region and increased levels of FMR1 mRNA. Molecular mechanisms leading to fragile X-premutation-associated conditions (FXPAC) include cotranscriptional R-loop formations, FMR1 mRNA toxicity through both RNA gelation into nuclear foci and sequestration of various CGG-repeat-binding proteins, and the repeat-associated non-AUG (RAN)-initiated translation of potentially toxic proteins. Such molecular mechanisms contribute to subsequent consequences, including mitochondrial dysfunction and neuronal death. Clinically, premutation carriers may exhibit a wide range of symptoms and phenotypes. Any of the problems associated with the premutation can appropriately be called FXPAC. Fragile X-associated tremor/ataxia syndrome (FXTAS), fragile X-associated primary ovarian insufficiency (FXPOI), and fragile X-associated neuropsychiatric disorders (FXAND) can fall under FXPAC. Understanding the molecular and clinical aspects of the premutation of the FMR1 gene is crucial for the accurate diagnosis, genetic counseling, and appropriate management of affected individuals and families. This paper summarizes all the known problems associated with the premutation and documents the presentations and discussions that occurred at the International Premutation Conference, which took place in New Zealand in 2023.

Comparative proteomic profiling of dystroglycan-associated proteins in wild type, mdx, and Galgt2 transgenic mouse skeletal muscle.

Dystroglycan is a major cell surface glycoprotein receptor for the extracellular matrix in skeletal muscle. Defects in dystroglycan glycosylation cause muscular dystrophy and alterations in dystroglycan glycosylation can impact extracellular matrix binding. Here we describe an immunoprecipitation technique that allows isolation of beta dystroglycan with members of the dystrophin-associated protein complex (DAPC) from detergent-solubilized skeletal muscle. Immunoprecipitation, coupled with shotgun proteomics, has allowed us to identify new dystroglycan-associated proteins and define changed associations that occur within the DAPC in dystrophic skeletal muscles. In addition, we describe changes that result from overexpression of Galgt2, a normally synaptic muscle glycosyltransferase that can modify alpha dystroglycan and inhibit the development of muscular dystrophy when it is overexpressed. These studies identify new dystroglycan-associated proteins that may participate in dystroglycan's roles, both positive and negative, in muscular dystrophy.

mdx(5cv) mice manifest more severe muscle dysfunction and diaphragm force deficits than do mdx Mice.

Duchenne muscular dystrophy (DMD) is characterized by progressive skeletal muscle dysfunction leading to premature death by the third decade of life. The mdx mouse, the most widely used animal model of DMD, has been extremely useful to study disease mechanisms and to screen new therapeutics. However, unlike patients with DMD, mdx mice have a very mild motor function deficit, posing significant limitations for its use as a platform to assess the impact of treatments on motor function. It has been suggested that an mdx variant, the mdx(5cv) mouse, might be more severely affected. Here, we compared the motor activity, histopathology, and individual muscle force measurements of mdx and mdx(5cv) mice. Our study revealed that mdx(5cv) mice showed more severe exercise-induced fatigue, Rotarod performance deficits, and gait anomalies than mdx mice and that these deficits began at a younger age. Muscle force studies showed more severe strength deficits in the diaphragm of mdx(5cv) mice compared to mdx mice, but similar force generation in the extensor digitorum longus. Muscle histology was similar between the two strains. Differences in genetic background (genetic modifiers) probably account for these functional differences between mdx strains. Overall, our findings indicate that the mdx and mdx(5cv) mouse models of DMD are not interchangeable and identify the mdx(5cv) mouse as a valuable platform for preclinical studies that require assessment of muscle function in live animals.

A Comparison of Adaptive Functioning Between Children With Duplication 7 Syndrome and Williams-Beuren Syndrome: A Pilot Investigation.

Interstitial deletions of 7q11.23 cause the well-known Williams-Beuren Syndrome (WBS), while duplication of the same region leads to duplication 7 syndrome (Dup7). Children with WBS share a distinct neurobehavioral phenotype including mild to severe intellectual disability, severely impaired visual spatial abilities, relatively preserved verbal expressive skills, anxiety problems, enhanced social motivation (i.e., hypersociable behaviors) and socio-communicative problems. Children with Dup7 syndrome exhibit some "inverted" features when compared to those of individuals with WBS, such as reduced social motivation and impairment of expressive language. Direct comparison of WBS and Dup7 represents a unique opportunity for the neurobehavioral characterization of the 7q11.23 section. However, most of the available data come from qualitative analysis between different studies. To the best of our knowledge, there are no studies directly comparing features of two matched samples of individuals with WBS and Dup7 syndromes. In this pilot study, we compare the adaptive functioning - measured with the Vineland Adaptive Behavior Scales, Second Edition - of two relatively small samples of children with molecularly confirmed diagnosis of WBS and Dup7 matched for IQ and chronological age, with a particular attention to socialization domain and expressive subdomain. Contrary to our assumption, we have not found any significant difference on socialization domain and expressive subdomains. This pilot investigation suggests that, when matched for chronological age and cognitive level, children with WBS and Dup7 share more similarities than expected. The inverted features that emerge in clinical settings on expressive language and social motivation seem not to differently interfere with the daily abilities to communicate and socialize with meaningful others during daily lives. Differences highlighted by previous undirected comparisons could be due to general and non-specific factors such as cognitive level, which is more severely impaired in individuals with WBS than Dup7. Implications for assessment and treatment are discussed.