Providing genetic testing and genetic counseling for Parkinson's disease to the community.

PURPOSE: To evaluate the feasibility and impact of offering genetic testing and counseling to patients with Parkinson's disease (PD), with the potential to enroll in gene-targeted clinical trials and improve clinical care. METHODS: A multicenter, exploratory pilot study at 7 academic hospital sites in the United States tracked enrollment and randomized participants to receive results and genetic counseling at local sites or by genetic counselors, remotely. Follow-up surveys measured participant/provider satisfaction, knowledge, and psychological impact. RESULTS: From September 5, 2019 to January 4, 2021, 620 participants were enrolled and 387 completed outcome surveys. There were no significant differences in outcomes between local and remote sites, with both arms reporting high knowledge and satisfaction scores (>80%). Notably, 16% of those tested had reportable PD gene variants (pathogenic/likely pathogenic/risk allele). CONCLUSION: Local clinicians, as well as genetic counselors, with educational support as needed, can effectively return genetic results for PD as we observed favorable outcome measures in both groups. Increasing access to PD genetic testing and counseling is urgent; this can inform future efforts to integrate genetic testing and counseling into clinical care for all those with PD.

Genetic testing for Parkinson disease: current practice, knowledge, and attitudes among US and Canadian movement disorders specialists.

PURPOSE: Genetic testing for Parkinson disease (PD) has not been widely used in clinical practice. In preparation for upcoming precision medicine-designed clinical trials for GBA and LRRK2, we evaluated movement disorders specialists' current practice, knowledge, attitudes, and barriers to genetic testing in PD. METHODS: An anonymous questionnaire was sent to movement disorders specialists at 146 Parkinson Study Group (PSG) sites in the United States (n = 131) and Canada (n = 15) to assess their knowledge and attitudes about genetic testing for PD. RESULTS: One hundred seventy-eight (47.6%) PSG clinicians completed the questionnaire. Forty-one percent of respondents had not referred any PD patients for genetic testing in the last year and >80% reported referring fewer than 11 patients over the same period. Most common reasons for not referring for genetic testing included lack of insurance coverage/cost to the patient and lack of perceived utility. On a scale of 0-100, the mean level of comfort in respondents' own ability to genetically counsel PD patients on GBA and LRRK2 was 52 (SD = 28). Sixty percent of clinicians correctly answered all questions about the inheritance and penetrance of GBA and LRRK2 variants. CONCLUSIONS: There is an urgent need to increase knowledge and reduce practical barriers to genetic counseling and testing in PD.

Correction: Genetic testing for Parkinson disease: current practice, knowledge, and attitudes among US and Canadian movement disorders specialists.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

MECR Mutations Cause Childhood-Onset Dystonia and Optic Atrophy, a Mitochondrial Fatty Acid Synthesis Disorder.

Mitochondrial fatty acid synthesis (mtFAS) is an evolutionarily conserved pathway essential for the function of the respiratory chain and several mitochondrial enzyme complexes. We report here a unique neurometabolic human disorder caused by defective mtFAS. Seven individuals from five unrelated families presented with childhood-onset dystonia, optic atrophy, and basal ganglia signal abnormalities on MRI. All affected individuals were found to harbor recessive mutations in MECR encoding the mitochondrial trans-2-enoyl-coenzyme A-reductase involved in human mtFAS. All six mutations are extremely rare in the general population, segregate with the disease in the families, and are predicted to be deleterious. The nonsense c.855T>G (p.Tyr285∗), c.247_250del (p.Asn83Hisfs∗4), and splice site c.830+2_830+3insT mutations lead to C-terminal truncation variants of MECR. The missense c.695G>A (p.Gly232Glu), c.854A>G (p.Tyr285Cys), and c.772C>T (p.Arg258Trp) mutations involve conserved amino acid residues, are located within the cofactor binding domain, and are predicted by structural analysis to have a destabilizing effect. Yeast modeling and complementation studies validated the pathogenicity of the MECR mutations. Fibroblast cell lines from affected individuals displayed reduced levels of both MECR and lipoylated proteins as well as defective respiration. These results suggest that mutations in MECR cause a distinct human disorder of the mtFAS pathway. The observation of decreased lipoylation raises the possibility of a potential therapeutic strategy.

Genetic counseling and testing for Huntington's disease: A historical review.

This manuscript describes the ways in which genetic counseling has evolved since John Pearson and Sheldon Reed first promoted "a genetic education" in the 1950s as a voluntary, non-directive clinical tool for permitting individual decision making. It reviews how the emergence of Huntington's disease (HD) registries and patient support organizations, genetic testing, and the discovery of a disease-causing CAG repeat expansion changed the contours of genetic counseling for families with HD. It also reviews the guidelines, outcomes, ethical and laboratory challenges, and uptake of predictive, prenatal, and preimplantation testing, and it casts a vision for how clinicians can better make use of genetic counseling to reach a broader pool of families that may be affected by HD and to ensure that genetic counseling is associated with the best levels of care. © 2016 Wiley Periodicals, Inc.

National Randomized Controlled Trial of Virtual House Calls for People with Parkinson's Disease: Interest and Barriers.

BACKGROUND: Delivering specialty care remotely directly into people's homes can enhance access for and improve the healthcare of individuals with chronic conditions. However, evidence supporting this approach is limited. MATERIALS AND METHODS: Connect.Parkinson is a randomized comparative effectiveness study that compares usual care of individuals with Parkinson's disease in the community with usual care augmented by virtual house calls with a Parkinson's disease specialist from 1 of 18 centers nationally. Individuals in the intervention arm receive four virtual visits from a Parkinson's disease specialist over 1 year via secure, Web-based videoconferencing directly into their homes. All study activities, including recruitment, enrollment, and assessments, are conducted remotely. Here we report on interest, feasibility, and barriers to enrollment in this ongoing study. RESULTS: During recruitment, 11,734 individuals visited the study's Web site, and 927 unique individuals submitted electronic interest forms. Two hundred ten individuals from 18 states enrolled in the study from March 2014 to June 2015, and 195 were randomized. Most participants were white (96%) and college educated (73%). Of the randomized participants, 73% had seen a Parkinson's disease specialist within the previous year. CONCLUSIONS: Among individuals with Parkinson's disease, national interest in receiving remote specialty care directly into the home is high. Remote enrollment in this care model is feasible but is likely affected by differential access to the Internet.

Common SNP-based haplotype analysis of the 4p16.3 Huntington disease gene region.

Age at the onset of motor symptoms in Huntington disease (HD) is determined largely by the length of a CAG repeat expansion in HTT but is also influenced by other genetic factors. We tested whether common genetic variation near the mutation site is associated with differences in the distribution of expanded CAG alleles or age at the onset of motor symptoms. To define disease-associated single-nucleotide polymorphisms (SNPs), we compared 4p16.3 SNPs in HD subjects with population controls in a case:control strategy, which revealed that the strongest signals occurred at a great distance from the HD mutation as a result of "synthetic association" with SNP alleles that are of low frequency in population controls. Detailed analysis delineated a prominent ancestral haplotype that accounted for ∼50% of HD chromosomes and extended to at least 938 kb on about half of these. Together, the seven most abundant haplotypes accounted for ∼83% of HD chromosomes. Neither the extended shared haplotype nor the individual local HTT haplotypes were associated with altered CAG-repeat length distribution or residual age at the onset of motor symptoms, arguing against modification of these disease features by common cis-regulatory elements. Similarly, the 11 most frequent control haplotypes showed no trans-modifier effect on age at the onset of motor symptoms. Our results argue against common local regulatory variation as a factor influencing HD pathogenesis, suggesting that genetic modifiers be sought elsewhere in the genome. They also indicate that genome-wide association analysis with a small number of cases can be effective for regional localization of genetic defects, even when a founder effect accounts for only a fraction of the disorder.

The relationship between obsessive-compulsive symptoms and PARKIN genotype: The CORE-PD study.

BACKGROUND: Few studies have systematically investigated the association between PARKIN genotype and psychiatric co-morbidities of Parkison's disease (PD). PARKIN-associated PD is characterized by severe nigral dopaminergic neuronal loss, a finding that may have implications for behaviors rooted in dopaminergic circuits such as obsessive-compulsive symptoms (OCS). METHODS: The Schedule of Compulsions and Obsessions Patient Inventory (SCOPI) was administered to 104 patients with early-onset PD and 257 asymptomatic first-degree relatives. Carriers of one and two PARKIN mutations were compared with noncarriers. RESULTS: Among patients, carriers scored lower than noncarriers in adjusted models (one-mutation: 13.9 point difference, P = 0.03; two-mutation: 24.1, P = 0.001), where lower scores indicate less OCS. Among asymptomatic relatives, a trend toward the opposite was seen: mutation carriers scored higher than noncarriers (one mutation, P = 0.05; two mutations, P = 0.13). CONCLUSIONS: First, a significant association was found between PARKIN mutation status and obsessive-compulsive symptom level in both PD and asymptomatic patients, suggesting that OCS might represent an early non-motor dopamine-dependent feature. Second, irrespective of disease status, heterozygotes were significantly different from noncarriers, suggesting that PARKIN heterozygosity may contribute to phenotype. © 2014 International Parkinson and Movement Disorder Society.

Experience, knowledge, and opinions about childhood genetic testing in Batten disease.

BACKGROUND AND OBJECTIVES: Policies for genetic testing in children (GTIC) focus on medical or psychosocial benefit to the child, discouraging or prohibiting carrier testing, and advising caution regarding pre-symptomatic diagnosis if no treatment exists. This study sought to understand parents' perspectives on these issues and determine their experiences and knowledge related to genetic testing for Batten disease - a set of inherited neurodegenerative diseases of childhood onset for which no disease modifying therapies yet exist. METHODS: Parents of children with Batten disease completed a survey of their knowledge of genetics, experience with genetic testing, and opinions regarding GTIC. RESULTS: 54% had sought genetic testing for non-affected family members, including predictive diagnosis of healthy, at-risk children. Participation in any genetic counseling was associated with greater knowledge on questions about genetics. The majority of parents felt it was better to know ahead of time that a child would develop Batten disease, believed that this knowledge would not alter how they related to their child, and that parents should have the final say in deciding whether to obtain GTIC. CONCLUSIONS: Parents of children with an inherited disease are knowledgeable about genetics and wish to establish predictive or carrier status of at-risk children.

Delivering Genetic Test Results for Parkinson Disease: A Qualitative Approach to Provider Experiences in the PD GENEration Study.

Background and Objectives: The PD GENEration (PD GENE) study (NCT04057794) is an interventional clinical trial offering genetic testing with result disclosure and genetic counseling to individuals with Parkinson disease (PD). In general, experiences of those providing PD genetic testing and counseling in a research or clinical setting have not been extensively evaluated. In this study, providers' experiences when providing research result disclosure and genetic counseling to people with PD were explored with the goal of improving PD genetics services. Methods: Qualitative semistructured interviews of all neurologists and genetic counselors who performed genetic test result disclosure and genetic counseling to at least 5 participants in the pilot portion of the PD GENE study were conducted. An inductive thematic analysis of the transcribed interviews identified core themes and subthemes for "lessons learned" and "challenges encountered." Results: Interviews were conducted with 14 providers (7 neurologists and 7 genetic counselors) who described multiple lessons learned while disclosing genetic test results, including the ability to adapt to participant background and needs and the value of a well-structured and supportive study that also provides training and educational materials for the provider. Of importance, responses suggested that the PD GENE study answered a real need, highlighting a strong interest in the community. Providers also voiced several shared challenges including the complexities of PD and PD genetics, unexpected confusion on provider roles within a research study, and complicated family histories/dynamics. Discussion: Providers in the pilot portion of the PD GENE study encountered enthusiasm and strong engagement from many of the participants, and they, too, voiced significant satisfaction about their roles and the mission of the study. They learned valuable lessons, and their comfort providing genetic test result disclosure and genetic counseling grew as the study progressed. Although there were challenges, they were deemed manageable. The results from this qualitative study can inform both the expanded PD GENE study and other providers offering genetic testing and counseling to their patients in a neurology setting. It will also allow for targeted PD provider education.

Clinical Review of Juvenile Huntington's Disease.

 Juvenile Huntington's disease (JHD) is rare. In the first decade of life speech difficulties, rigidity, and dystonia are common clinical motor symptoms, whereas onset in the second decade motor symptoms may sometimes resemble adult-onset Huntington's disease (AOHD). Cognitive decline is mostly detected by declining school performances. Behavioral symptoms in general do not differ from AOHD but may be confused with autism spectrum disorder or attention deficit hyperactivity disorder and lead to misdiagnosis and/or diagnostic delay. JHD specific features are epilepsy, ataxia, spasticity, pain, itching, and possibly liver steatosis. Disease progression of JHD is faster compared to AOHD and the disease duration is shorter, particularly in case of higher CAG repeat lengths. The diagnosis is based on clinical judgement in combination with a positive family history and/or DNA analysis after careful consideration. Repeat length in JHD is usually > 55 and caused by anticipation, usually via paternal transmission. There are no pharmacological and multidisciplinary guidelines for JHD treatment. Future perspectives for earlier diagnosis are better diagnostic markers such as qualitative MRI and neurofilament light in serum.

Candidate glutamatergic and dopaminergic pathway gene variants do not influence Huntington's disease motor onset.

Huntington's disease (HD) is a neurodegenerative disorder characterized by motor, cognitive, and behavioral disturbances. It is caused by the expansion of the HTT CAG repeat, which is the major determinant of age at onset (AO) of motor symptoms. Aberrant function of N-methyl-D-aspartate receptors and/or overexposure to dopamine has been suggested to cause significant neurotoxicity, contributing to HD pathogenesis. We used genetic association analysis in 1,628 HD patients to evaluate candidate polymorphisms in N-methyl-D-aspartate receptor subtype genes (GRIN2A rs4998386 and rs2650427, and GRIN2B rs1806201) and functional polymorphisms in genes in the dopamine pathway (DAT1 3' UTR 40-bp variable number tandem repeat (VNTR), DRD4 exon 3 48-bp VNTR, DRD2 rs1800497, and COMT rs4608) as potential modifiers of the disease process. None of the seven polymorphisms tested was found to be associated with significant modification of motor AO, either in a dominant or additive model, after adjusting for ancestry. The results of this candidate-genetic study therefore do not provide strong evidence to support a modulatory role for these variations within glutamatergic and dopaminergic genes in the AO of HD motor manifestations.

Factors Associated With the Place of Death in Huntington Disease: Analysis of Enroll-HD.

Background: Most people prefer to die at home. Hospice is the standard in end-of-life care for people with Huntington disease (HD), a neurodegenerative genetic disorder that affects people in middle adulthood. Yet, we have little knowledge regarding the place of death for people with HD. Therefore, the current state of knowledge limits HD clinicians' ability to conduct high-quality goals of care conversations. Objectives: We sought to determine the factors associated with the place of death in people with HD. Design: We obtained cross-sectional data from Enroll-HD and included participants with a positive HD mutation of 36 or more CAG repeats. Results: Out of 16,120 participants in the Enroll-HD study, 536 were reported as deceased. The mean age at death was 60. The leading place of death was home (29%), followed by the hospital (23%). The adjusted odds ratio (aOR) of dying at a skilled nursing facility was significantly lower for those partnered (aOR: 0.48, confidence interval [95% CI]: 0.26-0.86). The aOR for dying on hospice compared to home was increased in a person with some college and above (aOR: 2.40, 95% CI: 1.21-4.75). Conclusions: Our data further suggest that models that predict the place of death for serious illnesses do not appear to generalize to HD. The distribution in the places of death within HD was not uniform. Our findings may assist HD clinicians in communication during goals of care conversations.

What we don't need to prove but need to do in multidisciplinary treatment and care in Huntington's disease: a position paper.

BACKGROUND: Huntington's disease is a complex neurodegenerative hereditary disease with symptoms in all domains of a person's functioning. It begins after a healthy start in life and leads through the relentless progression over many years to complete care dependency and finally death. To date, the disease is incurable. The long progressive complex nature of the disease demands multiple disciplines for treatment and care of patient and family. These health care providers need inter- and multidisciplinary collaboration to persevere and be efficacious in this devastating disease trajectory. DISCUSSION: The position paper outlines current knowledge and experience alongside the experience and consensus of a recognised group of HD multidisciplinary experts. Additionally the patient's voice is clear and calls for health care providers with a holistic view on patient and family. Building long-term trust is a cornerstone of the network around the patient. This paper describes a managed care network comprising all the needed professionals and services. In the health care system, the role of a central coordinator or case manager is of key importance but lacks an appropriate guideline. Other disciplines currently without guidelines are general practitioners, nurses, psychologists, and social workers. Guidelines for neurologists, psychiatrists, geneticists, occupational therapists, speech and language therapists, physiotherapists, dieticians, and dentists are being discussed. Apart from all these profession-specific guidelines, distinctive inter- and multidisciplinary collaboration requirements must be met. CONCLUSIONS AND RECOMMENDATIONS: The complex nature of Huntington's disease demands multidisciplinary treatment and care endorsed by international regulations and the lay association. Available guidelines as reviewed in this paper should be used, made available by a central body, and updated every 3-5 years. Time needs to be invested in developing missing guidelines but the lack of this 'proof' should not prevent the 'doing' of good care.

Advance Care Planning and Health-Related Quality of Life in Huntington Disease: Results from a Multicenter National Study.

Objective: With Huntington disease (HD), a fatal neurodegenerative disease where the prevalence of suicidal thoughts and behavior (STB) remains elevated as compared to other neurological disorders, it is unknown whether STB and health-related quality of life (HRQoL) affect plans for the end of life or more broadly, advance care planning (ACP). Conversely, it is unknown whether ACP would provoke future changes to STB and HRQoL. Therefore, we sought to evaluate whether STB and HRQoL patient-reported outcomes (PROs) contribute to ACP and whether ACP relates to changes in STB and HRQoL at 24 months. Methods: HD-validated clinician- and patient-assessments (i.e., HRQoL PROs) were obtained at baseline enrollment, 12 and 24 months through our multi-center study (HDQLIFE™) throughout the United States among people with premanifest, early-stage, and late-stage manifest HD. We used linear mixed-effects models to determine the relationships between STB and HRQoL at baseline and HDQLIFE End of Life Planning at follow-up. Separate linear mixed-effects models were used to assess the relationship between HDQLIFE End of Life Planning at baseline, and HRQoL and STB at 12 and 24 months. False discovery rate adjustments were used to account for multiple comparisons. Results: At baseline enrollment, STB and HRQoL were not related to HDQLIFE End of Life Planning at 12 or 24 months. Similarly, at baseline, HDQLIFE End of Life Planning demonstrated no association with STB or HRQoL at 12 or 24 months. Interpretation: STB and HRQoL PROs do not significantly affect patient engagement with ACP. Most importantly, engaging in ACP does not cause untoward effects on HRQoL or STB for this rare neurodegenerative disease where the lifetime prevalence of STB approaches 30%.

Death Anxiety in Huntington Disease: Longitudinal Heath-Related Quality-of-Life Outcomes.

Objective: Death anxiety, represented by the HDQLIFE™ Concern with Death and Dying (CwDD) patient-reported outcome (PRO) questionnaire, captures a person's worry about the death and dying process. Previous work suggests that death anxiety remains an unremitting burden throughout all stages of Huntington disease (HD). Although palliative interventions have lessened death anxiety among people with advanced cancer, none has yet to undergo testing in the HD population. An account of how death anxiety is associated with longitudinal changes to aspects of health-related quality of life (HRQoL) would help optimize neuropalliative interventions for people with HD. Methods: HDQLIFE collected PROs concerning physical, mental, social, and cognitive HRQoL domains and clinician-rated assessments from people with HD at baseline and 12 and 24 months. Linear mixed-effects models were created to determine how baseline death anxiety was associated with follow-up changes in HRQoL PROs after controlling for baseline death anxiety and other disease and sociodemographic covariates. Results: Higher baseline HDQLIFE CwDD is associated with 12- and 24-month declines in HDQLIFE Speech Difficulties, neurology quality of life (NeuroQoL) Depression, Suicidality, HDQLIFE Meaning and Purpose, and NeuroQoL Positive Affect and Well-being. Interpretation: Death anxiety may be a risk factor for worsening mental health and speech difficulty. A further prospective study is required to evaluate whether interventions on death anxiety or mental health generally can reduce declines in HRQoL for people with HD over time.

Population stratification may bias analysis of PGC-1α as a modifier of age at Huntington disease motor onset.

Huntington's disease (HD) is an inherited neurodegenerative disorder characterized by motor, cognitive and behavioral disturbances, caused by the expansion of a CAG trinucleotide repeat in the HD gene. The CAG allele size is the major determinant of age at onset (AO) of motor symptoms, although the remaining variance in AO is highly heritable. The rs7665116 SNP in PPARGC1A, encoding the mitochondrial regulator PGC-1α, has been reported to be a significant modifier of AO in three European HD cohorts, perhaps due to affected cases from Italy. We attempted to replicate these findings in a large collection of (1,727) HD patient DNA samples of European origin. In the entire cohort, rs7665116 showed a significant effect in the dominant model (p value = 0.008) and the additive model (p value = 0.009). However, when examined by origin, cases of Southern European origin had an increased rs7665116 minor allele frequency (MAF), consistent with this being an ancestry-tagging SNP. The Southern European cases, despite similar mean CAG allele size, had a significantly older mean AO (p < 0.001), suggesting population-dependent phenotype stratification. When the generalized estimating equations models were adjusted for ancestry, the effect of the rs7665116 genotype on AO decreased dramatically. Our results do not support rs7665116 as a modifier of AO of motor symptoms, as we found evidence for a dramatic effect of phenotypic (AO) and genotypic (MAF) stratification among European cohorts that was not considered in previously reported association studies. A significantly older AO in Southern Europe may reflect population differences in genetic or environmental factors that warrant further investigation.

TAA repeat variation in the GRIK2 gene does not influence age at onset in Huntington's disease.

Huntington's disease is a neurodegenerative disorder caused by an expanded CAG trinucleotide repeat whose length is the major determinant of age at onset but remaining variation appears to be due in part to the effect of genetic modifiers. GRIK2, which encodes GluR6, a mediator of excitatory neurotransmission in the brain, has been suggested in several studies to be a modifier gene based upon a 3' untranslated region TAA trinucleotide repeat polymorphism. Prior to investing in detailed studies of the functional impact of this polymorphism, we sought to confirm its effect on age at onset in a much larger dataset than in previous investigations. We genotyped the HD CAG repeat and the GRIK2 TAA repeat in DNA samples from 2,911 Huntington's disease subjects with known age at onset, and tested for a potential modifier effect of GRIK2 using a variety of statistical approaches. Unlike previous reports, we detected no evidence of an influence of the GRIK2 TAA repeat polymorphism on age at motor onset. Similarly, the GRIK2 polymorphism did not show significant modifier effect on psychiatric and cognitive age at onset in HD. Comprehensive analytical methods applied to a much larger sample than in previous studies do not support a role for GRIK2 as a genetic modifier of age at onset of clinical symptoms in Huntington's disease.

Therapy in Huntington's disease: where are we?

As of 2012, almost 20 years after the discovery of the causative gene, clinical research has yet to find a disease-modifying treatment for Huntington's disease. However, both pharmacologic and nonpharmacologic therapies are available for many of the common symptoms of the disease. Recent studies of gene-positive patients in the prodromal, not clinically diagnosable, stages of the disease, are changing our perception of when the process of neurodegeneration begins. Once disease-modifying therapies become available, the approach to the diagnosis of Huntington's disease will likely shift from an examination-based clinical diagnosis, to one that includes a more complex combination of imaging, examination, and biomarker analysis.