Enhancing Clinical Infrastructure for the Delivery of Intrathecal and Genetic Therapies: A Qalsody (Tofersen) Model for Patients With SOD1-ALS.

Background: Qalsody (tofersen), an intrathecal therapy (IT) antisense oligonucleotide (ASO), was granted accelerated approval by the Food and Drug Administration for the treatment of SOD1-mediated amyotrophic lateral sclerosis (ALS) on April 25, 2023. Academic centers need to be prepared for expedited drug delivery. The purpose of this model was to predict the number of SOD1-ALS patients whom we expect to see at our center at the time of Qalsody approval and to use it to extrapolate to a model for a hypothetical sporadic IT ALS therapy. Recent Findings: We predicted that 6 symptomatic and 14 presymptomatic SOD1 patients would come to our center, whereas a sporadic therapy would generate 108 patients, creating excess office visits, lumbar punctures, and genetic counseling visits. Implications for Practice: As new therapies for neurologic diseases come to market, preparing for increased office volume and complex drug delivery are essential for optimal care.

The Importance of Offering Exome or Genome Sequencing in Adult Neuromuscular Clinics.

Advances in gene-specific therapeutics for patients with neuromuscular disorders (NMDs) have brought increased attention to the importance of genetic diagnosis. Genetic testing practices vary among adult neuromuscular clinics, with multi-gene panel testing currently being the most common approach; follow-up testing using broad-based methods, such as exome or genome sequencing, is less consistently offered. Here, we use five case examples to illustrate the unique ability of broad-based testing to improve diagnostic yield, resulting in identification of SORD-neuropathy, HADHB-related disease, ATXN2-ALS, MECP2 related progressive gait decline and spasticity, and DNMT1-related cerebellar ataxia, deafness, narcolepsy, and hereditary sensory neuropathy type 1E. We describe in each case the technological advantages that enabled identification of the causal gene, and the resultant clinical and personal implications for the patient, demonstrating the importance of offering exome or genome sequencing to adults with NMDs.

Genetic testing in adults with neurologic disorders: indications, approach, and clinical impacts.

The role of genetic testing in neurologic clinical practice has increased dramatically in recent years, driven by research on genetic causes of neurologic disease and increased availability of genetic sequencing technology. Genetic testing is now indicated for adults with a wide range of common neurologic conditions. The potential clinical impacts of a genetic diagnosis are also rapidly expanding, with a growing list of gene-specific treatments and clinical trials, in addition to important implications for prognosis, surveillance, family planning, and diagnostic closure. The goals of this review are to provide practical guidance for clinicians about the role of genetics in their practice and to provide the neuroscience research community with a broad survey of current progress in this field. We aim to answer three questions for the neurologist in practice: Which of my patients need genetic testing? What testing should I order? And how will genetic testing help my patient? We focus on common neurologic disorders and presentations to the neurology clinic. For each condition, we review the most current guidelines and evidence regarding indications for genetic testing, expected diagnostic yield, and recommended testing approach. We also focus on clinical impacts of genetic diagnoses, highlighting a number of gene-specific therapies recently approved for clinical use, and a rapidly expanding landscape of gene-specific clinical trials, many using novel nucleotide-based therapeutic modalities like antisense oligonucleotides and gene transfer. We anticipate that more widespread use of genetic testing will help advance therapeutic development and improve the care, and outcomes, of patients with neurologic conditions.

Rare Gain-of-Function KCND3 Variant Associated with Cerebellar Ataxia, Parkinsonism, Cognitive Dysfunction, and Brain Iron Accumulation.

Loss-of-function mutations in the KV4.3 channel-encoding KCND3 gene are linked to neurodegenerative cerebellar ataxia. Patients suffering from neurodegeneration associated with iron deposition may also present with cerebellar ataxia. The mechanism underlying brain iron accumulation remains unclear. Here, we aim to ascertain the potential pathogenic role of KCND3 variant in iron accumulation-related cerebellar ataxia. We presented a patient with slowly progressive cerebellar ataxia, parkinsonism, cognitive impairment, and iron accumulation in the basal ganglia and the cerebellum. Whole exome sequencing analyses identified in the patient a heterozygous KCND3 c.1256G>A (p.R419H) variant predicted to be disease-causing by multiple bioinformatic analyses. In vitro biochemical and immunofluorescence examinations revealed that, compared to the human KV4.3 wild-type channel, the p.R419H variant exhibited normal protein abundance and subcellular localization pattern. Electrophysiological investigation, however, demonstrated that the KV4.3 p.R419H variant was associated with a dominant increase in potassium current amplitudes, as well as notable changes in voltage-dependent gating properties leading to enhanced potassium window current. These observations indicate that, in direct contrast with the loss-of-function KCND3 mutations previously reported in cerebellar ataxia patients, we identified a rare gain-of-function KCND3 variant that may expand the clinical and molecular spectra of neurodegenerative cerebellar disorders associated with brain iron accumulation.

Temporal trends and yield of clinical diagnostic genetic testing in adult neurology.

While genetics evaluation is increasingly utilized in adult neurology patients, its usage and efficacy are not well characterized. Here, we report our experience with 1461 consecutive patients evaluated in an adult neurogenetics clinic at a large academic medical center between January 2015 and March 2020. Of the 1461 patients evaluated, 1215 patients were referred for the purposes of identifying a genetic diagnosis for an undiagnosed condition, 90.5% of whom underwent genetic testing. The modalities of genetic testing utilized varied across referral diagnostic categories, including a range of utilization of whole exome sequencing (WES) as an initial test in 13.9% of neuromuscular patients to 52.9% in white matter disorder patients. The usage of WES increased over time, from 7.7% of initial testing in 2015 to a peak of 27.3% in 2019. Overall, genetic testing yielded a causal genetic diagnosis in 30.7% of patients. This yield was higher in certain referring diagnosis categories, such as neuromuscular (39.0%) and epilepsy (29.8%). Our study demonstrates that evaluation at an adult neurogenetics referral center can yield diagnoses in a substantial fraction of patients. Additional research will be needed to determine optimal genetic testing strategies and cost effectiveness of adult neurogenetics evaluation.

A Novel SPAST/SPG4 Splice-Site Variant in a Family with Dominant Hereditary Spastic Paraplegia.

Some causes of spastic paraplegia are treatable and many are not. Diagnostic work-up to determine the etiology can be costly and invasive. Here we report the case of a man with slowly progressive spastic paraparesis. Using a multigene next-generation sequencing (NGS) panel, we identified a novel variant in the consensus splice site of the SPAST gene (exon 13, c.1536G>A, heterozygous), affecting codon 512 of the SPAST mRNA. The observed variant segregated with the disease in four tested family members. In this case, genetic confirmation obviated the need for additional testing such as MRI and lumbar puncture and helped the patient and his family understand his condition and prognosis. We conclude with a brief discussion of the SPG4/SPAST gene and the role of multigene panels in the diagnosis and management of hereditary spastic paraplegia.

Addressing the Value of Multidisciplinary Clinical Care in Huntington's Disease: A Snapshot of a New Huntington's Disease Center.

BACKGROUND: Clinical care for Huntington's disease (HD) is often provided in experienced centers that provide multidisciplinary care. However, the value of these centers and their uptake by HD families remain unknown. OBJECTIVE: To describe the services provided by a new HD center, including estimates of capture of the population served. METHODS: Retrospective review of a HD Center launched in 2015, including quantitative and qualitative data on clinic visits, demographic and clinical data. RESULTS: We observed a rapid and ongoing growth on the annual number of clinic encounters, with high demand for in-clinic multidisciplinary care. Using census data and estimates of HD prevalence, we determined that we served about 20% of local patients with HD. Most HD patients received pharmacological treatment for psychiatric symptoms, and over half were treated for chorea. About 25% of new HD diagnoses were on patients without family history of HD. Finally, the demand for predictive testing in at risk individuals significantly increased following the press release reporting the successful completion of the Ionis-HTTRx (RG 6042) trial. CONCLUSIONS: This report indicates a high demand for multidisciplinary care by HD families, supporting its value, providing a snapshot of the organization and function of a single center. Furthermore, it demonstrates how dissemination of news related to research advances influence clinical behavior. Reporting similar information from other HD centers to would provide us with a more global view of the status of HD care across multiple geographical areas.

Attitudes of Potential Participants Towards Molecular Therapy Trials in Huntington's Disease.

BACKGROUND: Advances in molecular therapeutic approaches in the last decade are translating into the design of non-traditional clinical trials. In order to improve their feasibility, it is important to understand the attitudes of potential participants towards these trials, their motivations to get involved and acceptance of risks. OBJECTIVE: We aimed to better understand the willingness of potential participants to participate in different molecular therapy trials for Huntington's disease (HD) based on their clinical and genetic status, trial design and goals of the treatment. METHODS: An anonymous survey was distributed through the Huntington's Disease Society of America (HDSA) on-line portal/website. Various hypothetical scenarios were presented followed by a survey consistent of Likert scale responses ascertaining willingness to participate, collecting demographic, clinical and genetic information. RESULTS: There were a total of 87 responses, including patients diagnosed with HD, pre-manifesting mutation carriers and asymptomatic participants at risk. The majority of participants indicated they were very likely or likely to participate in clinical trials independent of study design or goals of the therapy, with a more favorable view in premanifesting mutation carriers. However, more invasive procedures and trials including placebo were less favorably viewed across all diagnostic groups. CONCLUSIONS: In summary, most individuals in the HD community would consider participation in novel molecular therapy trials, but study design and goals could impact patient recruitment. This data can be used to inform the recruitment and consent process into clinical trials and to address common concerns by potential participants.

Correction: Loss of the BMP Antagonist, SMOC-1, Causes Ophthalmo-Acromelic (Waardenburg Anophthalmia) Syndrome in Humans and Mice.

[This corrects the article DOI: 10.1371/journal.pgen.1002114.].

The ClinGen Epilepsy Gene Curation Expert Panel-Bridging the divide between clinical domain knowledge and formal gene curation criteria.

The field of epilepsy genetics is advancing rapidly and epilepsy is emerging as a frequent indication for diagnostic genetic testing. Within the larger ClinGen framework, the ClinGen Epilepsy Gene Curation Expert Panel is tasked with connecting two increasingly separate fields: the domain of traditional clinical epileptology, with its own established language and classification criteria, and the rapidly evolving area of diagnostic genetic testing that adheres to formal criteria for gene and variant curation. We identify critical components unique to the epilepsy gene curation effort, including: (a) precise phenotype definitions within existing disease and phenotype ontologies; (b) consideration of when epilepsy should be curated as a distinct disease entity; (c) strategies for gene selection; and (d) emerging rules for evaluating functional models for seizure disorders. Given that de novo variants play a prominent role in many of the epilepsies, sufficient genetic evidence is often awarded early in the curation process. Therefore, the emphasis of gene curation is frequently shifted toward an iterative precuration process to better capture phenotypic associations. We demonstrate that within the spectrum of neurodevelopmental disorders, gene curation for epilepsy-associated genes is feasible and suggest epilepsy-specific conventions, laying the groundwork for a curation process of all major epilepsy-associated genes.

Hereditary Myoclonus Dystonia: A Novel SGCE Variant and Phenotype Including Intellectual Disability.

Background: Hereditary myoclonus dystonia is often due to changes in the SGCE gene. Dystonia (DYT)-SGCE has a variable phenotype that can involve focal or generalized myoclonus and various forms of task-specific, segmental, or generalized dystonia. Psychiatric comorbidities are common. Case Report: We report a case of a young woman with generalized myoclonus, dystonia, and intellectual disability. She was found to have a novel SGCE splice site variant. Discussion: This novel variant is very likely pathogenic by in silico analysis and has not been previously reported. Additionally, her intellectual disability may constitute a novel phenotype for patients with SGCE variants.

Genetic test utilization and diagnostic yield in adult patients with neurological disorders.

To determine the diagnostic yield of different genetic test modalities in adult patients with neurological disorders, we evaluated all adult patients seen for genetic diagnostic evaluation in the outpatient neurology practice at the University of Pennsylvania between January 2016 and April 2017 as part of the newly created Penn Neurogenetics Program. Subjects were identified through our electronic medical system as those evaluated by the Program's single clinical genetic counselor in that period. A total of 377 patients were evaluated by the Penn Neurogenetics Program in different settings and genetic testing recommended. Of those, 182 (48%) were seen in subspecialty clinic setting and 195 (52%) in a General Neurogenetics Clinic. Genetic testing was completed in over 80% of patients in whom it was recommended. The diagnostic yield was 32% across disease groups. Stratified by testing modality, the yield was highest with directed testing (50%) and array comparative genomic hybridization (45%), followed by gene panels and exome testing (25% each). In conclusion, genetic testing can be successfully requested in clinic in a large majority of adult patients. Age is not a limiting factor for a genetic diagnostic evaluation and the yield of clinical testing across phenotypes (almost 30%) is consistent with previous phenotype-focused or research-based studies. These results should inform the development of specific guidelines for clinical testing and serve as evidence to improve reimbursement by insurance payers.

Systemic diagnostic testing in patients with apparently isolated uveal coloboma.

PURPOSE: To investigate the frequency and types of systemic findings in patients with apparently isolated uveal coloboma. DESIGN: Cross-sectional observational study. METHODS: setting: Single-center ophthalmic genetics clinic. study population: Ninety-nine patients with uveal coloboma seen at the National Eye Institute. observational procedure: Results of audiology testing, echocardiogram, brain magnetic resonance imaging, renal ultrasound, and total spine radiographs. main outcome measure: Prevalence of abnormal findings on systemic testing. RESULTS: Uveal coloboma affected only the anterior segment in 8 patients, only the posterior segment in 23 patients, and both anterior and posterior segments in 68 patients. Best-corrected visual acuity (BCVA) of eyes with coloboma was ≥20/40 in 45% of eyes; 23% of eyes had BCVA of ≤20/400. The majority of patients (74%) had good vision (>20/60) in at least 1 eye. Ten of the 19 patients (53%) who underwent echocardiography had abnormalities, with ventral septal defects being the most prevalent. Abnormal findings were observed in 5 of 72 patients (7%) who had a renal ultrasound and in 5 of 29 patients (17%) who underwent a brain MRI. Audiology testing revealed abnormalities in 13 of 75 patients (17%), and spine radiographs showed anomalies in 10 of 77 patients (13%). Most findings required no acute intervention. CONCLUSIONS: Although some patients with coloboma had evidence of extraocular abnormalities, the majority of findings on routine clinical examination did not require acute intervention, but some warranted follow-up. Results from the systemic evaluation of patients with coloboma should be interpreted with caution and in view of their clinical context.

The genetics of anophthalmia and microphthalmia.

PURPOSE OF REVIEW: To summarize recent breakthroughs regarding the genes known to play a role in normal ocular development in humans and to elucidate the role mutations in these genes play in anophthalmia and microphthalmia. RECENT FINDINGS: The main themes discussed within this article are the various documented genetic advances in identifying the various causes of anophthalmia and microphthalmia. In addition, the complex interplay of these genes during critical embryonic development will be addressed. SUMMARY: The recent identification of many eye development genes has changed the ability to identify a cause of anophthalmia and microphthalmia in many individuals. Syndrome identification and the availability of genetic testing underscores the desirability of evaluation by a geneticist for all individuals with anophthalmia and microphthalmia in order to provide appropriate management, long-term guidance, and genetic counseling.

Loss of the BMP antagonist, SMOC-1, causes Ophthalmo-acromelic (Waardenburg Anophthalmia) syndrome in humans and mice.

Ophthalmo-acromelic syndrome (OAS), also known as Waardenburg Anophthalmia syndrome, is defined by the combination of eye malformations, most commonly bilateral anophthalmia, with post-axial oligosyndactyly. Homozygosity mapping and subsequent targeted mutation analysis of a locus on 14q24.2 identified homozygous mutations in SMOC1 (SPARC-related modular calcium binding 1) in eight unrelated families. Four of these mutations are nonsense, two frame-shift, and two missense. The missense mutations are both in the second Thyroglobulin Type-1 (Tg1) domain of the protein. The orthologous gene in the mouse, Smoc1, shows site- and stage-specific expression during eye, limb, craniofacial, and somite development. We also report a targeted pre-conditional gene-trap mutation of Smoc1 (Smoc1(tm1a)) that reduces mRNA to ∼10% of wild-type levels. This gene-trap results in highly penetrant hindlimb post-axial oligosyndactyly in homozygous mutant animals (Smoc1(tm1a/tm1a)). Eye malformations, most commonly coloboma, and cleft palate occur in a significant proportion of Smoc1(tm1a/tm1a) embryos and pups. Thus partial loss of Smoc-1 results in a convincing phenocopy of the human disease. SMOC-1 is one of the two mammalian paralogs of Drosophila Pentagone, an inhibitor of decapentaplegic. The orthologous gene in Xenopus laevis, Smoc-1, also functions as a Bone Morphogenic Protein (BMP) antagonist in early embryogenesis. Loss of BMP antagonism during mammalian development provides a plausible explanation for both the limb and eye phenotype in humans and mice.