Neuromuscular and cardiovascular phenotypes in paediatric titinopathies: a multisite retrospective study.

Background: Pathogenic variants in cause a spectrum of autosomal dominant and recessive cardiovascular, skeletal muscle and cardioskeletal disease with symptom onset across the lifespan. The aim of this study was to characterise the genotypes and phenotypes in a cohort of +paediatric patients.

Methods: Retrospective chart review was performed at four academic medical centres.

Validation of the parent-proxy version of the pediatric Charcot-Marie-Tooth disease quality of life instrument for children aged 0-7 years.

Objective: To evaluate the parent-proxy version of the pediatric Charcot Marie Tooth specific quality of life (pCMT-QOL) outcome instrument for children aged 7 or younger with CMT. We have previously developed and validated the direct-report pCMT-QOL for children aged 8-18 years and a parent proxy version of the instrument for children 8-18 years old. There is currently no CMT-QOL outcome measure for children aged 0-7 years old.

Validation of the parent-proxy pediatric Charcot-Marie-Tooth disease quality of life outcome measure.

Charcot-Marie-Tooth disease (CMT) reduces health-related quality of life (QOL) in children. We have previously developed and validated the English and Italian versions of the pediatric CMT-specific QOL outcome measure (pCMT-QOL) for children aged 8 to 18. There is currently no parent-proxy CMT QOL outcome measure for use in clinical trials, which could provide complementary information in these children and adolescents.

Disease Progression in Charcot-Marie-Tooth Disease Related to MPZ Mutations: A Longitudinal Study.

Objective: The paucity of longitudinal natural history studies in MPZ neuropathy remains a barrier to clinical trials. We have completed a longitudinal natural history study in patients with MPZ neuropathies across 13 sites of the Inherited Neuropathies Consortium.

Methods: Change in Charcot-Marie-Tooth Examination Score (CMTES) and Rasch modified CMTES (CMTES-R) were evaluated using longitudinal regression over a 5-year period in subjects with MPZ neuropathy.

A longitudinal study of CMT1A using Rasch analysis based CMT neuropathy and examination scores.

Objective: To evaluate the sensitivity of Rasch analysis-based, weighted Charcot-Marie-Tooth Neuropathy and Examination Scores (CMTNS-R and CMTES-R) to clinical progression in patients with Charcot-Marie-Tooth disease type 1A (CMT1A).

Methods: Patients with CMT1A from 18 sites of the Inherited Neuropathies Consortium were evaluated between 2009 and 2018. Weighted CMTNS and CMTES modified category responses were developed with Rasch analysis of the standard scores.

Positive Attitudes and Therapeutic Misconception Around Hypothetical Clinical Trial Participation in the Huntington's Disease Community.

Background: New therapies that could modify the disease course of Huntington's disease (HD) are entering clinical trials. However, conceptions about clinical research from the HD community are unknown. This knowledge could help inform patient-clinician discussions surrounding clinical trial participation.

Supervision in genetic counselor training in North America: A systematic review.

Genetic counseling has been a profession for over 40 years, and training programs accredited by the Accreditation Council for Genetic Counseling are required to have students supervised in at least 50 patient-facing cases prior to graduation. However, there is no standardized information or training for supervisors of genetic counseling students. As a first step toward creating formal and standardized supervision training, we undertook a systematic review of the genetic counseling student supervision literature.

Perspectives on Spinraza (Nusinersen) Treatment Study: Views of Individuals and Parents of Children Diagnosed with Spinal Muscular Atrophy.

Background: Spinal muscular atrophy (SMA) is a genetic disorder characterized by muscle loss. In December 2016 the FDA approved the first and only treatment drug for SMA: Spinraza (nusinersen). Despite excitement and optimism, there are no published data on the perceptions of individuals with SMA and their families about the benefits, risks, and challenges associated with treatment.

"This could be me": exploring the impact of genetic risk for Huntington's disease young caregivers.

Huntington's disease (HD) is a predominantly adult-onset, genetic, neurodegenerative condition. Children of affected individuals have a 50% risk of inheriting HD and often assume caregiving roles for their parent. Studies specifically focused on HD young caregivers have proposed that the genetic risk component of HD "exacerbates" the caregiving experience and identified common responsibilities, burdens, and support needs, but none have explored the relationship between the caregiving role and perception of genetic risk.

Charcot Marie Tooth disease type 4J with complex central nervous system features.

We describe a family with Charcot Marie Tooth disease type 4J presenting with features of Charcot Marie Tooth disease plus parkinsonism and aphemia. Genetic testing found two variants in the gene: c.122T>C (p.

Loss-of-Function Mutations in LGI4, a Secreted Ligand Involved in Schwann Cell Myelination, Are Responsible for Arthrogryposis Multiplex Congenita.

Arthrogryposis multiplex congenita (AMC) is a developmental condition characterized by multiple joint contractures resulting from reduced or absent fetal movements. Through genetic mapping of disease loci and whole-exome sequencing in four unrelated multiplex families presenting with severe AMC, we identified biallelic loss-of-function mutations in LGI4 (leucine-rich glioma-inactivated 4). LGI4 is a ligand secreted by Schwann cells that regulates peripheral nerve myelination via its cognate receptor ADAM22 expressed by neurons.

Impact of Huntington Disease Gene-Positive Status on Pre-Symptomatic Young Adults and Recommendations for Genetic Counselors.

Huntington disease (HD) is an autosomal dominant, progressive neurodegenerative disorder for which there is no cure. Predictive testing for HD is available to asymptomatic at-risk individuals. Approximately half of the population undergoing predictive testing for HD consists of young adults (≤35 years old).

Novel mutations highlight the key role of the ankyrin repeat domain in TRPV4-mediated neuropathy.

Objective: To characterize 2 novel TRPV4 mutations in 2 unrelated families exhibiting the Charcot-Marie-Tooth disease type 2C (CMT2C) phenotype.

Methods: Direct CMT gene testing was performed on 2 unrelated families with CMT2C. A 4-fold symmetric tetramer model of human TRPV4 was generated to map the locations of novel TRPV4 mutations in these families relative to previously identified disease-causing mutations (neuropathy, skeletal dysplasia, and osteoarthropathy).

Genotype-phenotype characteristics and baseline natural history of heritable neuropathies caused by mutations in the MPZ gene.

We aimed to characterize genotype-phenotype correlations and establish baseline clinical data for peripheral neuropathies caused by mutations in the myelin protein zero (MPZ) gene. MPZ mutations are the second leading cause of Charcot-Marie-Tooth disease type 1. Recent research makes clinical trials for patients with MPZ mutations a realistic possibility.

Genetic testing practices for Charcot-Marie-Tooth type 1A disease.

Introduction: Charcot-Marie-Tooth disease type 1A (CMT1A) is caused by a PMP22 gene duplication. CMT1A has a robust electrical phenotype that can be used to direct genetic testing. We compared specialty CMT center CMT1A diagnosis rates to those of outside physicians.

A review of genetic counseling for Charcot Marie Tooth disease (CMT).

Charcot Marie Tooth disease (CMT) encompasses the inherited peripheral neuropathies. While four genes have been found to cause over 90 % of genetically identifiable causes of CMT (PMP22, GJB1, MPZ, MFN2), at least 51 genes and loci have been found to cause CMT when mutated, creating difficulties for clinicians to find a genetic subtype for families. Here, the classic features of CMT as well as characteristic features of the most common subtypes of CMT are described, as well as methods for narrowing down the possible subtypes.

Anterior tibialis CMAP amplitude correlations with impairment in CMT1A.

Introduction: CMT1A is the most common form of Charcot-Marie-Tooth disease (CMT), a slowly progressive neuropathy in which impairment is length dependent. Fibular nerve conduction studies to the anterior tibialis muscle (AT) may serve as a physiological marker of disease progression in patients with CMT1A. The objective of this study is to determine whether the AT compound muscle action potential (CMAP) amplitude correlates with impairment in patients with CMT1A.

X inactivation in females with X-linked Charcot-Marie-Tooth disease.

X-linked Charcot-Marie-Tooth disease (CMT1X) is the second most common inherited neuropathy, caused by mutations in gap junction beta-1 (GJB1). Males have a uniformly moderately severe phenotype while females have a variable phenotype, suggested to be due to X inactivation. We aimed to assess X inactivation pattern in females with CMT1X and correlate this with phenotype using the CMT examination score to determine whether the X inactivation pattern accounted for the variable phenotype in females with CMT1X.

Genetics of neuropathies.

Charcot-Marie-Tooth disease (CMT) encompasses the heritable motor and sensory neuropathies that comprise most of the inherited peripheral neuropathies. Due to the great genetic heterogeneity of the condition, it can be difficult to determine what type of CMT a person has. The major phenotypic features of the CMT subtypes are delineated, as well as recommendations for focused genetic testing.

Phenotype expression in women with CMT1X.

Charcot-Marie-Tooth disease type 1X (CMT1X) is the second most common inherited peripheral neuropathy. Women with CMT1X typically have a less severe phenotype than men, perhaps because of X-inactivation patterns. Our objective was to determine the phenotype of women with CMT1X and whether X-inactivation patterns in white blood cells (WBCs) differ between females with CMT1X and controls.