Comparing knowledge and attitudes towards genetic testing in Parkinson's disease in an American and Asian population

Genetic Testing of Movements Disorders: A Review of Clinical Utility

Currently, pathogenic variants in more than 500 different genes are known to cause various movement disorders. The increasing accessibility and reducing cost of genetic testing has resulted in increasing clinical use of genetic testing for the diagnosis of movement disorders. However, the optimal use case(s) for genetic testing at a patient level remain ill-defined. Here, we review the utility of genetic testing in patients with movement disorders and also highlight current challenges and limitations that need to be considered when making decisions about genetic testing in clinical practice.

Highlights

The utility of genetic testing extends across multiple clinical and non-clinical domains. Here we review different aspects of the utility of genetic testing for movement disorders and the numerous associated challenges and limitations. These factors should be weighed on a case-by-case basis when requesting genetic tests in clinical practice.

Genetic literacy and attitude towards genetic testing in patients with Parkinson's disease and their caregivers: A review of literature

BACKGROUND

Genetic literacy refers to an individual's ability to understand the basics of genetic concepts and apply them to health-related decisions. The level of genetic literacy influences attitude towards genetic testing and is, in turn, influenced by several other factors. Clinicians must be aware of the genetic literacy of their patients and their caregivers before advising genetic testing and/or undertaking pre and post-test counseling.

METHOD

A systematic review of literature in PubMed was carried out using keywords "Genetic testing", "Genetic counseling", "Knowledge", "Attitude", "Parkinson's disease" in various combinations.

RESULTS

Seven eligible studies with a total of 1837 individuals (patients with PD-1355 and patient caregivers-482) were identified. More than half the participants were well-versed in basic concepts of genetics (57.8%) and risks of inheriting PD (60.5%) while less than 10% were aware regarding the contribution of specific genes (e.g. LRRK2). Interest in diagnosis, treatment, prevention and facilitating PD research were central themes for positive attitude while apprehensions revolving around impact on employment and insurance and non-benefit were associated with negative attitudes. Possible associations included greater knowledge scores with positive attitudes towards genetic testing and older age for negative attitude towards testing. Insufficient data on attitudes toward prenatal testing, presymptomatic testing and clinicians' attitude toward testing was identified.

CONCLUSION

Patients with PD and their caregivers are aware of the role of genetics in the etiopathogenesis of their disease, which contributes to their positive attitude towards testing. Further studies exploring negative attitudes towards testing will help overcome the hurdles in genetic testing and counseling in this cohort of patients.

Evaluation of Knowledge and Attitudes of the Population of Tabuk City Regarding Parkinson's Disease: A Cross-Sectional Study

BACKGROUND

The lack of awareness and information about PD may be a barrier to early diagnosis and the delivery of the best care to patients with the condition, given its rising prevalence. In order to determine the variables that are connected to these parameters, this study sought to ascertain the general public's knowledge and awareness of PD in Tabuk City.

METHODS

 In Tabuk City, a cross-sectional demographic survey was carried out. A validated structured questionnaire was used to interview adult respondents by random sampling regarding specific knowledge, attitudes, and awareness related to Parkinson's disease. According to the density of the city, a total of 426 members of the general population were chosen at random and interviewed by skilled interviewers.

RESULTS

 Age and educational attainment were independently linked to PD awareness. Bachelor's degree subjects and those between the ages of 18 and 45 displayed a greater awareness of PD. Those above 60 and those between the ages of 46 and 60 lacked sufficient knowledge. The majority of participants demonstrated adequate understanding and awareness of PD in their respective occupations.

CONCLUSIONS

 Age, gender, occupation, and level of education were all adequately covered by knowledge and understanding of PD. To increase public knowledge, attitudes, and awareness of PD, however, suitable educational tactics and approaches targeting particular subgroups are required.

Genetic Testing in Parkinson's Disease

Genetic testing for persons with Parkinson's disease is becoming increasingly common. Significant gains have been made regarding genetic testing methods, and testing is becoming more readily available in clinical, research, and direct-to-consumer settings. Although the potential utility of clinical testing is expanding, there are currently no proven gene-targeted therapies, but clinical trials are underway. Furthermore, genetic testing practices vary widely, as do knowledge and attitudes of relevant stakeholders. The specter of testing mandates financial, ethical, and physician engagement, and there is a need for guidelines to help navigate the myriad of challenges. However, to develop guidelines, gaps and controversies need to be clearly identified and analyzed. To this end, we first reviewed recent literature and subsequently identified gaps and controversies, some of which were partially addressed in the literature, but many of which are not well delineated or researched. Key gaps and controversies include: (1) Is genetic testing appropriate in symptomatic and asymptomatic individuals without medical actionability? (2) How, if at all, should testing vary based on ethnicity? (3) What are the long-term outcomes of consumer- and research-based genetic testing in presymptomatic PD? (4) What resources are needed for clinical genetic testing, and how is this impacted by models of care and cost-benefit considerations? Addressing these issues will help facilitate the development of consensus and guidelines regarding the approach and access to genetic testing and counseling. This is also needed to guide a multidisciplinary approach that accounts for cultural, geographic, and socioeconomic factors in developing testing guidelines. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

The Genetic Testing Experience of Individuals with Parkinson's Disease

Background

The perspective and experiences of individuals with Parkinson's disease (PD) regarding genetic testing is limited.

Objectives

To determine if anticipated benefits and negative consequences of genetic testing noted in prior studies have occurred in a surveyed group of patients with PD and to identify reasons why some individuals with PD have not had testing.

Methods

Individuals were surveyed from 22 support/advocacy groups throughout the US. Information about patient demographics and genetic testing were assessed, along with the consequences experienced after testing or anticipated by those who have not had testing. Descriptive statistics, Pearson correlation coefficient, ANOVA, and independent sample t-test were utilized for data analysis.

Results

Of the genetic testing group (n = 78), most received testing through a research study (44.9%) or a Direct-to-Consumer company (46.2%). Most did not meet with a genetic counselor before (87.2%) or after testing (64.1%). Fewer positive and fewer negative consequences were reported after testing compared to the consequences anticipated by those who have not undergone testing (P < 0.001, all comparisons). Of the non-genetic testing group (n = 166), 49.4% did not undergo testing because they were not aware it was available and 38.0% because their doctor did not offer it.

Conclusions

Findings demonstrate the need for providers to have genetic testing discussions with PD patients, who may otherwise seek testing via Direct-to-Consumer companies or be unaware it is available. Collaborations with genetic counselors trained in providing anticipatory guidance may assist patients in forming more realistic expectations regarding the consequences experienced after genetic testing for PD.

Genetic counseling and testing for Asian Americans: a systematic review

PURPOSE

Asian Americans have been understudied in the literature on genetic and genomic services. The current study systematically identified, evaluated, and summarized findings from relevant qualitative and quantitative studies on genetic health care for Asian Americans.

METHODS

A search of five databases (1990 to 2018) returned 8,522 unique records. After removing duplicates, abstract/title screening, and full text review, 47 studies met inclusion criteria. Data from quantitative studies were converted into "qualitized data" and pooled together with thematic data from qualitative studies to produce a set of integrated findings.

RESULTS

Synthesis of results revealed that (1) Asian Americans are under-referred but have high uptake for genetic services, (2) linguistic/communication challenges were common and Asian Americans expected more directive genetic counseling, and (3) Asian Americans' family members were involved in testing decisions, but communication of results and risk information to family members was lower than other racial groups.

CONCLUSION

This study identified multiple barriers to genetic counseling, testing, and care for Asian Americans, as well as gaps in the research literature. By focusing on these barriers and filling these gaps, clinical genetic approaches can be tailored to meet the needs of diverse patient groups, particularly those of Asian descent.

Impacts of apolipoprotein E disclosure on healthy Asian older adults: a cohort study

BACKGROUND

The apolipoprotein E (APOE) genotype provides information about Alzheimer's disease risk, yet genotype disclosure is discouraged due to concerns about possible distress. This is the first study investigating the psychological and behavioral impacts that genetic susceptibility testing for Alzheimer's disease has in an Asian population.

METHODS

From March 2016 to November 2017, we ran a prospective cohort study at Duke-National University of Singapore Medical School. 280 healthy Chinese elderly filled in questionnaires that measured psychological symptoms and health behaviors, 1 week before and 6 weeks after APOE genotype disclosure. Responses from ε4-positive subjects (associated with greater Alzheimer's disease risk) were compared to responses from ε4-negative subjects.

RESULTS

ε4 presence was not significantly associated with anxiety (p = 0.09) or depression (p = 0.25). No associations were found for changes to diet (p = 0.36), dietary supplements consumption (p = 0.90), physical activity (p = 0.15), or cognitive activity (p = 0.18).

CONCLUSION

There is no evidence to suggest that disclosure of APOE to Asian populations was associated with any short-term adverse psychological or behavioral impacts.

Physician and patient determinants of prognostic counseling in idiopathic REM sleep-behavior disorder

OBJECTIVES/BACKGROUND

Prognostic counseling about the risk for developing overt neurodegenerative disorders for patients with idiopathic REM sleep-behavior disorder (iRBD) and isolated REM sleep without atonia (iRSWA) is difficult, given lack of disease-modifying interventions and uncertainty in accurate prognostication for individuals. We aimed to analyze patient and physician characteristics associated with documented prognostic discussions for patients with iRBD and iRSWA.

PATIENTS/METHODS

We retrospectively reviewed the medical records for 138 (112 iRBD and 26 iRSWA) patients seen at the Mayo Clinic between 2012 and 2015. We analyzed physician and patient demographics, initial complaint, and other information discussed during office visits. We then comparatively analyzed the impact of physician and patient characteristics on documented prognostic discussions using Chi Square or Fischer's exact test.

RESULTS

Mean iRBD patient age was 65.0 ± 13.0, and mean iRSWA age was 58 ± 15 years. Seventy-eight (69.6%) iRBD and 22 (84.6%) iRSWA patients were men. Sixty-two (55%) iRBD and three (12%) iRSWA patients received prognostic counseling about phenoconversion risk. iRBD was a secondary complaint in 67 (59.8%). Patients over age 60 years and those having iRBD as a chief complaint more frequently received prognostic discussions than those with opposite characteristics (all p < 0.05). Patient sex and antidepressant use were not associated with counseling. Sleep neurologists disclosed prognostic information most frequently, with male more likely than female clinicians to disclose prognoses.

CONCLUSIONS

Several patient and physician characteristics appear to influence documented prognostic counseling for iRBD/RSWA patients. Future studies of iRBD/RSWA patients' preferences are needed to clarify ethically appropriate physician-patient communication concerning prognosis.

International survey of patients undergoing percutaneous coronary intervention and their attitudes toward pharmacogenetic testing

OBJECTIVE

To evaluate perceptions toward pharmacogenetic testing of patients undergoing percutaneous coronary intervention (PCI) who are prescribed dual antiplatelet therapy (DAPT) and whether geographical differences in these perceptions exist.

PARTICIPANTS AND METHODS

TAILOR-PCI is the largest genotype-based cardiovascular clinical trial randomizing participants to conventional DAPT or prospective genotyping-guided DAPT. Enrolled patients completed surveys before and 6 months after randomization.

RESULTS

A total of 1327 patients completed baseline surveys of whom 28, 29, and 43% were from Korea, Canada and the USA, respectively. Most patients (77%) valued identifying pharmacogenetic variants; however, fewer Koreans (44%) as compared with Canadians (91%) and USA (89%) patients identified pharmacogenetics as being important (P<0.001). After adjusting for age, sex, and country, those who were confident in their ability to understand genetic information were significantly more likely to value identifying pharmacogenetic variants (odds ratio: 30.0; 95% confidence interval: 20.5-43.8). Only 21% of Koreans, as opposed to 86 and 77% of patients in Canada and USA, respectively, were confident in their ability to understand genetic information (P<0.001).

CONCLUSION

Although genetically mediated clopidogrel resistance is more prevalent amongst Asians, Koreans undergoing PCI identified pharmacogenetic variants as less important to their healthcare, likely related to their lack of confidence in their ability to understand genetic information. To enable successful implementation of pharmacogenetic testing on a global scale, the possibility of international population differences in perceptions should be considered.

GBA-Associated Parkinson's Disease and Other Synucleinopathies

PURPOSE OF REVIEW

GBA mutations are the most common known genetic cause of Parkinson's disease (PD). Its biological pathway may be important in idiopathic PD, since activity of the enzyme encoded by GBA, glucocerebrosidase, is reduced even among PD patients without GBA mutations. This article describes the structure and function of GBA, reviews recent literature on the clinical phenotype of GBA PD, and suggests future directions for research, counseling, and treatment.

RECENT FINDINGS

Several longitudinal studies have shown that GBA PD has faster motor and cognitive progression than idiopathic PD and that this effect is dose dependent. New evidence suggests that GBA mutations may be important in multiple system atrophy. Further, new interventional studies focusing on GBA PD are described. These studies may increase the interest of PD patients and caregivers in genetic counseling. GBA mutation status may help clinicians estimate PD progression, though mechanisms underlying GBA and synucleinopathy require further understanding.

Awareness and attitude of the public toward personalized medicine in Korea

OBJECTIVES

As personalized medicine (PM) is expected to greatly improve health outcomes, efforts have recently been made for its clinical implementation in Korea. We aimed to evaluate public awareness and attitude regarding PM.

METHODS

We performed a self-administered questionnaire survey to 703 adults, who participated in the survey on a voluntary basis. The primary outcome measures included public knowledge, attitude, and acceptance of PM. We conducted multinomial multivariate logistic analysis for outcome variables with three response categories and performed multivariate logistic regression analyses for dichotomous outcome variables.

RESULTS

Only 28% of participants had knowledge that genetic factors can contribute to inter-individual variations in drug response and the definition of PM (199 out of 702). Higher family income was correlated with greater knowledge concerning PM (OR = 3.76, p = 0.034). A majority of respondents preferred integrated pharmacogenomic testing over drug-specific testing and agreed to inclusion of pharmacogenomic testing in the national health examination (64% and 77%, respectively), but only 51% were willing to pay for it.

DISCUSSION

Our results identify the urgent need for public education as well as the potential health disparities in access to PM. This study helps to frame policies for implementing PM in clinical practice.

A qualitative study on Singaporean women's views towards breast cancer screening and Single Nucleotide Polymorphisms (SNPs) gene testing to guide personalised screening strategies

Background

Breast cancer is the top cancer by incidence and mortality in Singaporean women. Mammography is by far its best screening tool, but current recommended age and interval may not yield the most benefit. Recent studies have demonstrated the potential of single nucleotide polymorphisms (SNPs) to improve discriminatory accuracy of breast cancer risk assessment models. This study was conducted to understand Singaporean women’s views towards breast cancer screening and SNPs gene testing to guide personalised screening strategies.

Methods

Focus group discussions were conducted among English-speaking women (n = 27) between 40 to 65 years old, both current and lapsed mammogram users. Women were divided into four groups based on age and mammogram usage. Discussions about breast cancer and screening experience, as well as perception and attitude towards SNPs gene testing were conducted by an experienced moderator. Women were also asked for factors that will influence their uptake of the test. Transcripts were analysed using thematic analysis to captured similarities and differences in views expressed.

Results

Barriers to repeat mammogram attendance include laziness to make appointment and painful and uncomfortable screening process. However, the underlying reason may be low perceived susceptibility to breast cancer. Facilitators to repeat mammogram attendance include ease of making appointment and timely reminders. Women were generally receptive towards SNPs gene testing, but required information on accuracy, cost, invasiveness, and side effects before they decide whether to go for it. Other factors include waiting time for results and frequency interval. On average, women gave a rating of 7.5 (range 5 to 10) when asked how likely they will go for the test.

Conclusion

Addressing concerns such as pain and discomfort during mammogram, providing timely reminders and debunking breast cancer myths can help to improve screening uptake. Women demonstrated a spectrum of responses towards a novel test like SNPs gene testing, but need more information to make an informed decision. Future public health education on predictive genetic testing should adequately address both benefits and risks. Findings from this study is used to inform a discrete choice experiment to empirically quantify women preferences and willingness-to-pay for SNPs gene testing.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3781-8) contains supplementary material, which is available to authorized users.

Attitudes Towards Prenatal Genetic Counseling, Prenatal Genetic Testing, and Termination of Pregnancy among Southeast and East Asian Women in the United States

Recognizing the heterogeneity of the Asian population with regards to acculturation, education, health awareness, and cultural values is vital for tailoring culturally sensitive and appropriate care. Prior studies show that cultural values influence perceptions of genetics within Asian populations. The reputation of the family unit factors into decisions such as pregnancy termination and disclosure of family medical history, and the nondirective model of American genetic counseling may conflict with the historical Asian model of paternalistic health care. Previous studies also provide conflicting evidence regarding correlations between education, acculturation, age, and awareness and perceptions of genetic testing. The aims of this study were to describe attitudes towards prenatal genetics among Southeast and East Asian women living in the United States for varying amounts of time and to explore sociocultural factors influencing those attitudes. Twenty-three Asian women who were members of Asian cultural organizations in the United States were interviewed via telephone about their attitudes towards prenatal genetic counseling, prenatal genetic testing, and termination of pregnancy. Responses were transcribed and coded for common themes using a thematic analysis approach. Four major themes emerged. In general, participants: (1) had diverse expectations for genetic counselors; (2) tended to weigh risks and benefits with regards to genetic testing decisions; (3) had mixed views on termination for lethal and non-lethal genetic conditions; and (4) identified cultural factors which influenced testing and termination such as lack of available resources, societal shame and stigma, and family pressure. These findings may allow prenatal genetic counselors to gain a richer, more nuanced understanding of their Asian patients and to offer culturally tailored prenatal genetic counseling.

The Level of Knowledge of Parkinson's Disease among Nonprofessional Caregivers in a Movement Disorders Center in Turkey

Introduction. Only a few studies have been conducted to determine the level of knowledge among caregivers about Parkinson's disease (PD). The aim of the current study was to determine the knowledge of PD among caregivers at a movement disorder clinic in Turkey. Methods. We conducted a questionnaire based interview with the subjects in a tertiary care neurology facility in Turkey. The questions were divided into two parts covering the symptomatology and treatment of PD. A questionnaire consisting of 10 questions was applied to the subjects who had to mark the correct option in a stipulated time. Results. Eighty caregivers were included in the study. The caregivers' mean age was 47.94 years (SD = 12.40). There were 47 female caregivers (58.8%). The most well-known question was that the number of drugs given to the patient may vary with time (76.3%), whereas “the benefit noted in the patient's treatment decreases over time” was the least known question (11.3%). Discussion. This study is the first in our country and shows the necessity to increase the knowledge of PD among caregivers and the public. Education programs may have a positive role in imparting knowledge to the caregivers of PD patients.

Knowledge, attitudes and perceptions of Parkinson's disease: A cross-sectional survey of Asian patients

BACKGROUND

A knowledge gap about Parkinson's disease (PD) often exists amongst PD patients, the level and accuracy of which can influence their attitude and perceptions about the disease. Increased awareness of this information deficit can help physicians identify interventions that will improve patient's knowledge and perceptions about PD.

OBJECTIVES

To evaluate general understanding of PD and identify knowledge gaps amongst PD patients using a validated PD knowledge questionnaire.

METHODS

A cross-sectional, questionnaire-based study was conducted in 108 PD patients (34 working; 74 retired). The questionnaire covers three domains of PD, including diagnosis, therapeutic options, and disease course with a total knowledge score ranging from 0 to 26. Subjects with dementia were excluded.

RESULTS

Patient misconceptions were reflected in the mean (SD) total, diagnosis, therapeutic options, and disease course scores: 14.64 (3.32), 7.76 (1.93), 3.85 (1.28), and 3.03 (1.41) respectively. The working age subgroup had significantly higher knowledge scores than the retired age group for the whole questionnaire (p=0.004), as well as the diagnosis (p=0.001) and therapeutic sections (p=0.023). Three dependent variables, including younger age at recruitment (<60years old), female gender, and higher disease duration (≥4years), were identified as predictors of a higher level of PD knowledge amongst PD patients.

CONCLUSION

Significant knowledge gaps were identified amongst PD patients in all three aspects of the questionnaire. Timely identification of patients with inaccurate or insufficient disease-related knowledge could help healthcare professionals choose more suitable multimodal educational interventions.

Retinoblastoma genetics in India: From research to implementation

Retinoblastoma is the prototypic genetic cancer. India carries the biggest burden of retinoblastoma globally, with an estimated 1500 new cases annually. Recent advances in retinoblastoma genetics are reviewed, focusing specifically on information with clinical significance to patients. The Indian literature on retinoblastoma clinical genetics is also highlighted, with a comment on challenges and future directions. The review concludes with recommendations to help clinicians implement and translate retinoblastoma genetics to their practice.

Genetic testing of LRRK2 in Parkinson's disease: is there a clinical role?

Genetic testing has played an important role for the diagnosis of many rare monogenic disorders. However, the role and limitations of genetic testing have generated considerable debate in the medical community. In recent years, the identification of several monogenic genes in Parkinson's disease (PD), a common neurodegenerative disorder, has led to calls for genetic testing guidelines for this disorder. Genetic testing of LRRK2 provides an excellent platform to highlight some of the pertinent issues (generic and specific) related to genetic testing in PD. The identification of a common recurrent mutation (G2019S) worldwide provides an opportunity for developing guidelines that are applicable internationally. However, the incomplete penetrance of the mutation and the lack of clarity of the pathogenicity of many other reported LRRK2 mutations call for cautious implementation of genetic testing programs. The clinical utility of genetic testing is compounded by easy accessibility of Direct to Consumer genetic services and the relative lack of regulation on reliability of service providers in internet advertisements. Based on current literature, genetic testing of LRRK2 (particularly for G2019S) certainly has a clinical role, though it is applicable primarily in select scenarios and in certain at-risk populations.

A review of quality of life after predictive testing for and earlier identification of neurodegenerative diseases

The past decade has witnessed an explosion of evidence suggesting that many neurodegenerative diseases can be detected years, if not decades, earlier than previously thought. To date, these scientific advances have not provoked any parallel translational or clinical improvements. There is an urgency to capitalize on this momentum so earlier detection of disease can be more readily translated into improved health-related quality of life for families at risk for, or suffering with, neurodegenerative diseases. In this review, we discuss health-related quality of life (HRQOL) measurement in neurodegenerative diseases and the importance of these "patient reported outcomes" for all clinical research. Next, we address HRQOL following early identification or predictive genetic testing in some neurodegenerative diseases: Huntington disease, Alzheimer's disease, Parkinson's disease, Dementia with Lewy bodies, frontotemporal dementia, amyotrophic lateral sclerosis, prion diseases, hereditary ataxias, Dentatorubral-pallidoluysian atrophy and Wilson's disease. After a brief report of available direct-to-consumer genetic tests, we address the juxtaposition of earlier disease identification with assumed reluctance toward predictive genetic testing. Forty-one studies examining health-related outcomes following predictive genetic testing for neurodegenerative disease suggested that (a) extreme or catastrophic outcomes are rare; (b) consequences commonly include transiently increased anxiety and/or depression; (c) most participants report no regret; (d) many persons report extensive benefits to receiving genetic information; and (e) stigmatization and discrimination for genetic diseases are poorly understood and policy and laws are needed. Caution is appropriate for earlier identification of neurodegenerative diseases but findings suggest further progress is safe, feasible and likely to advance clinical care.

Knowledge and attitudes towards genetic testing in those affected with Parkinson's disease

Advances in genetic tests provide valuable information for clinicians and patients around risks and inheritance of Parkinson's Disease (PD); however, questions arise whether those affected or at risk of PD will want genetic testing, particularly given that there are no preventive or disease-modifying therapies currently available. This study sought to determine knowledge and attitudes toward genetic testing for those affected with PD. A cross-sectional study was undertaken using a standardized questionnaire with six multi-choice genetic knowledge and 17 multi-choice attitude items. Participants were selected from a registry of people affected with PD living in Queensland, Australia. Half of the selected index cases had a family history of PD. Ordinal regression was used to evaluate the association between support for genetic testing and demographic, knowledge, and other attitudinal factors. The level of genetic knowledge was relatively low (37 % correct responses). The vast majority supported diagnostic testing (97 %) and 90 % would undertake a genetic test themselves. Support for predictive was lower (78 %) and prenatal genetic testing had the least support (58 %). Benefits of testing were identified as the ability to know the child's risk, seek therapies, and helping science with finding a cure. Concerns about genetic testing included potential emotional reactions and test accuracy. Genetic knowledge was not significantly associated with attitudes towards genetic testing. Patients with PD have strong interest in genetic testing for themselves with support for diagnostic testing but less support for predictive and prenatal testing. Genetic knowledge was unrelated to testing attitudes.

Knowledge of and interest in genetic results among Parkinson disease patients and caregivers

The purpose of the study is to investigate Parkinson disease (PD) patients' and caregivers' knowledge of and interest in genetic testing. Gaucher disease (GD) results from recessive mutations in glucocerebrosidase (GBA). Both heterozygote GBA carriers and GD patients are at greater risk for PD. Studies regarding knowledge of and interest in genetic testing have been limited and have not offered genetic results to participants. In this study, 353 PD patients and 180 caregivers were recruited to a PD genetic study. The association between GD, GBA mutations and PD was described to participants who reported their familiarity with genetic terms, answered questions on genetic concepts, and indicated their interest in knowing if they may have GD (two GBA mutations) and other genetic information that could impact their health. Ninety-three-percent of participants were interested in receiving GBA results; however, only 51.6 % of PD participants and 55.6 % of caregivers knew that "scientists have identified genes associated with a higher risk of developing PD." PD patients may benefit from education and genetic counseling on the implications of genetic testing.

Next-generation sequencing diagnostics for neurological diseases/disorders: from a clinical perspective

Neurological diseases encompass a broad, heterogeneous group of disorders ranging from pediatric neurodevelopmental diseases to late-onset neurodegenerative diseases, most of which are poorly understood and few of which are curable. Most of these diseases have a genetic basis and thus are expected to be amenable to genetic or genomic analysis by next-generation sequencing (NGS). While the advancement of contemporary technologies (such as NGS) is exciting, translating this tool into actual benefit for patients and clinicians can be challenging. In a clinical setting, a sequencing test that is fast, non-invasive, cheap and with perfect specificity would be ideal. However, in practice, there are several hurdles and caveats to consider even before a NGS diagnostic testing can be optimally applied. Proper definition of clinical phenotype, selection of the most appropriate subjects and the clinical setting, optimization of both sensitivity and specificity of the test, evaluation of the availability of the infrastructure and expertise, and consideration of economic, ethical and legal issues are vital in the final application of NGS diagnostic screening in the clinics.

Willingness-to-pay and preferences for warfarin pharmacogenetic testing in Chinese warfarin patients and the Chinese general public

Aim: Genetic factors have been found to affect warfarin maintenance dose and a key factor for the successful clinical implementation of warfarin pharmacogenetic testing (WPGT) is economic sustainability. We aimed to estimate the willingness-to-pay (WTP) and preferences for WPGT in Singaporean Chinese subjects. Methods & subjects: A total of 197 warfarin patients and 187 members of the public completed a questionnaire. The discrete choice methodology was used and the choice model was estimated using hierarchical Bayes. Marginal WTP, attribute importance and WTP for three hypothetical WPGTs were calculated from the estimated utilities. Results: Both patients and the public placed most emphasis on side effects, followed by cost, number of International Normalized Ratio tests and ‘nature of test’. WTP for WPGT ranged from S$160 to S$730. Conclusion: WPGTs are likely to be economically sustainable.

What is the role of genetic testing in movement disorders practice?

Genetic testing holds many promises in movement disorders, but also pitfalls that require careful consideration for meaningful results. These include the primary indication for testing in the first place, concerns regarding the implications of symptomatic, presymptomatic, and susceptibility testing, the mutation frequency in the gene of interest, the general lack of neuroprotective treatment options for neurodegenerative movement disorders, the prognosis of the condition diagnosed, and patient confidentiality concerns. Furthermore, new technical achievements and the available technical expertise, feasibility of specific gene testing, and its coverage through a health insurance carrier should be considered. Guidelines for testing have been established by some disease societies to advise clinicians and in parallel legal regulations are being adjusted at a national and international level. We review these and other critical points and recent developments regarding genetic testing in the field of movement disorders.

Genetic testing and Parkinson disease: assessment of patient knowledge, attitudes, and interest

The most common genetic contributor to late-onset Parkinson disease (PD) is the LRRK2 gene. In order to effectively integrate LRRK2 genetic testing into clinical practice, a strategy tailored to the PD population must be developed. We assessed 168 individuals with PD for baseline knowledge of genetics, perceived risk, and interest and opinions regarding genetic counseling and testing. Most participants felt that they were familiar with general genetics terms but overall knowledge levels were low, with an average score of 55%. The majority of participants thought it was likely they inherited a PD gene (72%), believed genetic testing for PD would be useful (86%), and were interested in genetic testing (59%) and genetic counseling (56%). However, only a few participants had heard of any genetic tests for PD (29%) or LRRK2 (10%). There appears to be a significant level of interest in genetics and genetic testing within the PD population, but a considerable deficit in genetics knowledge and an over-estimation of risk. Genetic education and counseling tools to address these needs were developed to provide patients with the ability to make informed and knowledgeable genetic testing decisions.

Genetic testing and counseling for hereditary neurological diseases in Mali

As genetic advances become incorporated into health care delivery, disparities between developing and developed countries may become greater. By addressing genetic health care needs and specific differences of developing countries, these disparities may be mitigated. We sought to describe the attitudes and knowledge of subjects with hereditary neurological diseases in Mali before and after receiving genetic testing and counseling for the first time. A questionnaire of attitudes and knowledge items was adapted and piloted for use in Mali. We found that the majority of subjects had positive attitudes toward genetic testing and counseling, both before and afterwards. Subjects responded to approximately half of the knowledge questions regarding hereditary transmission correctly before and after genetic testing and counseling. Neither overall attitudes nor knowledge scores changed significantly from baseline. Concerns about confidentiality were expressed by the majority of subjects. These findings indicate that, despite limited knowledge of patterns of inheritance, Malians understood the sensitive nature of this information and were favorable toward receiving genetic testing and counseling for diagnostic and prognostic purposes.

Survey of US public attitudes toward pharmacogenetic testing

To assess public attitudes and interest in pharmacogenetic (PGx) testing, we conducted a random-digit-dial telephone survey of US adults, achieving a response rate of 42% (n=1139). Most respondents expressed interest in PGx testing to predict mild or serious side effects (73±3.29 and 85±2.91%, respectively), guide dosing (91%) and assist with drug selection (92%). Younger individuals (aged 18-34 years) were more likely to be interested in PGx testing to predict serious side effects (vs aged 55+ years), as well as Whites, those with a college degree, and who had experienced side effects from medications. However, most respondents (78±3.14%) were not likely to have a PGx test if there was a risk that their DNA sample or test result could be shared without their permission. Given differences in interest among some groups, providers should clearly discuss the purpose of testing, alternative testing options (if available) and policies to protect patient privacy and confidentiality.

LRRK2 in Parkinson's disease: genetic and clinical studies from patients

Mutations in leucine-rich repeat kinase 2 (LRRK2) (PARK8) are associated with both familial and sporadic forms of Parkinson's disease. Most studies have shown that LRRK2 mutations may explain between 5% and 13% of familial and 1-5% of sporadic Parkinson's disease. Importantly, a common recurrent mutation (G2019S) located in the kinase domain has been reported across most ethnic populations, with the highest prevalence among Ashkenazi Jews and North African Arabs. A recent worldwide meta-analysis pooling data from 24 populations reported a higher occurrence of G2019S in southern than in northern European countries and the penetrance is estimated to be approximately 75% at the age of 79 years. The R1441 'hotspot' amino acid codon residue (G/H/C) in the Ras of complex proteins domain is the second most common site of pathogenic LRRK2 substitutions after G2019S, with most carriers developing symptoms by the age of 75 years. Two polymorphic variants found almost exclusively among Asians (G2385R and R1628P) have been shown to increase the Parkinson's disease risk by approximately two-fold. The mutational event associated with R1628P is more recent, occurring approximately 2500 years ago, compared to estimates of 4000 years for G2385R carriers. LRRK2 mutation carriers generally simulate late onset Parkinson's disease and present with the usual typical clinical features. Genetic testing for G2019S in sporadic late-onset Parkinson's disease can be considered in some situations and may be useful in populations with high carrier status. The identification of asymptomatic mutation and risk variant carriers provides a unique opportunity for recruiting these subjects in potential neuroprotective trials and longitudinal studies to identify biomarkers of neurodegeneration.

Validity of family history in essential tremor

In this study, we found the sensitivity and specificity of family history data given by essential tremor (ET) patients to be 43.3% and 94.4%. Compared to relatives with less severe tremor (tremor score <24), those with more severe tremor (tremor score 24) were more likely to be identified by the ET probands (8/8 vs. 5/22, p=0.001, chi2 14.3). Our study suggests that family history information reported by ET patients was inaccurate, and poorly validated. Clinical and genetic studies in ET should take the limitation of family history data into consideration.