Why So Many Patients With Movement Disorders Never Get Genetic Testing — and What Could Change That

Table of Contents

• Key Points
• Background: Why Genetic Testing Matters in Movement Disorders
• Recognising Who Should Be Offered Genetic Testing
• How Clinician Attitudes Create a Barrier
• Cost, Availability and Access to Testing
• Choosing the Right Genetic Test
• Access to Genetic Counselling
• Fear of Genetic Discrimination
• The Pathway Forward: What Could Fix These Barriers
• What This Means for Patients
• Limitations of This Review
• Practical Recommendations for Patients
• Frequently Asked Questions
• Source Information

Key Points

• Up to 15% of people with Parkinson's disease carry a reportable genetic variant, according to the ROPAD and PD GENEration studies.
• Barriers to testing include cost, unequal access, clinician knowledge gaps, limited counselling, and fears about genetic discrimination.
• In a large Italian longitudinal study, Parkinson's patients with GBA1 variants had good motor benefit from deep brain stimulation but worsening cognition over three years.
• More than half of surveyed International Parkinson and Movement Disorder Society members reported low or no access to genetic counselling in their region.
• Research programmes such as ROPAD, PD GENEration and the Global Parkinson's Genetics Program have provided free, clinically accredited testing and counselling.

Background: Why Genetic Testing Matters in Movement Disorders

Over the past few decades, genetic testing has transformed how doctors diagnose a wide range of movement disorders — conditions that affect a person's ability to control movement, such as tremor, stiffness, slowness and unsteady walking. Testing is clearly valuable for disorders with straightforward inherited patterns, such as Huntington's disease (HD, a progressive inherited brain disorder).

Increasingly, it also matters for conditions long thought to be "sporadic," meaning they appear without any family history. Parkinson's disease (PD) is the best example. Testing is not only improving diagnosis rates. It is also opening the door to treatment. A growing number of symptom-relieving and disease-modifying therapies (treatments that aim to slow the disease itself) are being developed for genetic movement disorders.

Despite this clear value, significant obstacles stand in the way of routine and widespread use of genetic testing in clinical practice. This review explores those barriers — from financial and technical considerations to complex social and demographic factors, and to worries about genetic discrimination.

Recognising Who Should Be Offered Genetic Testing

The first step in genetic diagnosis is simple: a doctor has to think of it. The list of movement disorders that may benefit from genetic testing keeps growing, and clinical guidelines need regular updating to keep clinicians informed.

Parkinson's disease was traditionally considered sporadic and "idiopathic" (of unknown cause). Two large recent studies changed that picture. The ROPAD study (Rostock Parkinson's Disease study) and the PD GENEration study together found a reportable genetic variant in up to 15% of all PD patients — roughly 1 in every 7 people with Parkinson's. In ROPAD, which used a 50-gene panel covering PD and related conditions, the diagnostic yield was 14.8%. In PD GENEration, which used a 7-gene PD panel with genetic counselling, the yield was 13%. These results have led to calls for genetic testing to become routine care for every patient with Parkinson's disease.

Deciding when and in whom to test — to maximise the chance of finding an answer while keeping costs reasonable — differs by disorder, because each has a different genetic architecture (the pattern of genes involved).

• Dystonia (involuntary muscle contractions causing twisting postures): a scoring algorithm combining age of onset, which body areas are affected, and whether other non-dystonic neurologic features are present can predict the diagnostic yield from whole exome sequencing. This helps guide which patients to test.
• Other movement disorders: in the absence of validated scoring systems, doctors can use similar clinical clues — age of onset, the presence of other features, and family history.

How Clinician Attitudes Create a Barrier

What doctors believe about genetic testing strongly influences whether they order it. A 2019 survey of North American movement disorder specialists in the Parkinson Study Group (PSG) found that a commonly cited reason for not testing PD patients was a perceived lack of usefulness — particularly for making treatment decisions.

That perception is not entirely accurate. It is true that no gene-specific PD treatments are currently approved. Even so, knowing a patient's genetic status can still shape care. For example, PD patients who carry GBA1 variants (changes in a gene linked to a higher risk of Parkinson's) appear to face an increased risk of cognitive decline after deep brain stimulation (DBS) of the subthalamic nucleus — a surgical treatment that implants electrodes deep in the brain — even though they still get good motor (movement) benefit. A large Italian longitudinal study showed that these patients gained good motor improvement from DBS but experienced worsening cognition in the three years afterwards. As a result, some experts propose that genetic testing should be offered to PD patients before DBS surgery, so that the risks and benefits can be discussed honestly beforehand.

Another practical benefit is access. Many clinical trials are currently running or planned for genetic forms of PD, especially those involving GBA1 and LRRK2. Genetic testing determines who can join them. Testing can also inform prognosis, guide reproductive decisions, and improve access to support services.

The same 2019 PSG survey found that clinicians often believed their PD patients did not want genetic testing. The evidence says otherwise. Survey-based studies of patients with PD have consistently shown that the majority of patients with PD are interested in undergoing genetic testing. This gap between what doctors assume and what patients actually want suggests a need for better clinician education.

Cost, Availability and Access to Testing

Genetic testing has become more available and gradually cheaper over time. Yet access problems and cost or health insurance coverage remain major barriers, according to movement disorder physicians. These barriers fall unevenly across the world.

Low- and middle-income countries, which together hold the vast majority of the world's population, are hit hardest. But even within high-income countries, social and demographic factors shape who gets tested and how quickly.

• A recent American study found that marginalised and minoritised demographic groups were half as likely to be evaluated by a neurogenetic service — a 50% lower chance — even though they benefit equally from genetic testing.
• The ENROL-HD study reported that in North America, Black patients with Huntington's disease were diagnosed 1 year later than non-Hispanic White patients with HD. The authors suggest delayed access to HD genetic testing and counselling may contribute to this gap.
• Low neighbourhood socioeconomic resource levels are linked to lower attendance at clinical genetics outpatient appointments.
• Limited English proficiency among patients and their families appears to delay access to genetic services.

Where local infrastructure and funding are lacking, research collaborations offer another route to testing. The ROPAD and PD GENEration projects delivered free, clinically accredited genetic testing and counselling to patients with PD on a massive scale. That proves large-scale delivery is possible.

Choosing the Right Genetic Test

Selecting the right test is harder than it sounds. The number of genes linked to genetic movement disorders keeps growing, and different types of genetic changes require different sequencing technologies and different computer analyses.

These variant types include single nucleotide variants (a change in one "letter" of DNA), insertions and deletions (missing or extra DNA segments), copy number variants (extra or missing copies of larger DNA sections), and short tandem repeat (STR) expansions (stretches of repeated DNA that grow too long).

Many doctors are unsure how to navigate this. In the 2019 PSG survey, 27% of respondents — about 1 in 4 — said they were unsure which test or laboratory to use for PD genetic testing. A 2021 study found that across commercial PD genetic tests, the number of genes tested ranged from 5 to 62, showing a clear need for consensus and standardisation.

Cost and availability must be weighed against diagnostic yield — the chance a test actually finds the cause.

• Targeted gene panels (testing a selected set of genes) are relatively cheap and are the most common test used by movement disorder physicians worldwide.
• Exome sequencing (reading all protein-coding DNA) and genome sequencing (reading nearly all DNA) are more comprehensive and more expensive. They are used far less often, but typically produce higher diagnostic yields.

Exome and genome sequencing have another advantage: stored data can be reanalysed later as new disease genes are discovered, without needing to re-sequence the patient. This reanalysis has been shown to improve diagnostic rates in several movement disorder datasets. A recent example is the discovery of RAB32 as a new gene for autosomal dominant PD (an inherited form where one altered gene copy is enough to cause disease), which was quickly confirmed by several other studies using reanalysis of existing exome or genome data. A patient who had only a targeted gene panel that never included RAB32 would not get this benefit.

Some genetic changes escape standard next-generation sequencing (NGS) entirely. The recently described GAA STR expansion in the FGF14 gene causes spinocerebellar ataxia 27B (SCA27B), now increasingly recognised as a very common cause of late-onset ataxia (progressive problems with balance and coordination). Access to clinically accredited testing for this expansion is limited even in many high-income countries. In the United States, clinical testing for SCA27B is performed by only two diagnostic laboratories.

Other newly identified STR expansions — including those causing spinocerebellar ataxia 4 and familial cortical myoclonic tremor with epilepsy — face the same problem. Long-read sequencing is a newer method that can detect many STR expansions at once, along with other variants that standard NGS misses. It promises to streamline diagnosis. However, it is only just beginning to enter clinical use, and its limited availability and higher cost remain barriers.

Access to Genetic Counselling

Genetic testing without genetic counselling is incomplete. Counselling helps patients understand what a result means, what it implies for family members, and what choices lie ahead. Yet access to counselling is a significant barrier in movement disorders.

The global genetic counselling workforce has grown in recent years. Even so, a recent survey of members of the International Parkinson and Movement Disorder Society (MDS) found that more than half of respondents reported low or no access to genetic counselling in their region.

Neurologists can provide counselling themselves, either instead of or alongside genetic counsellors and clinical geneticists. But in the 2019 PSG survey, only 50–60% of PD clinicians felt adequately equipped to do so. The PD GENEration study showed it can work: specifically trained neurologists successfully delivered genetic counselling and returned results to patients.

Time is another obstacle. Proper, nuanced genetic counselling takes time — and movement disorder clinics are busy, with many competing priorities such as discussing the diagnosis, prognosis and treatments.

Fear of Genetic Discrimination

Some patients hesitate to be tested because they worry a genetic result could affect their job or their ability to get insurance. These concerns vary by ethnicity and by how much a person knows about genetics.

A survey of American and Asian PD patients found that American patients were more likely to worry that genetic testing might affect their employability and their eligibility for health or life insurance. In both groups, these concerns were influenced by how much the patient understood about genetics.

Patients are not alone in this. The PSG survey found that PD clinicians also worried about impacts on their patients' employability and insurability.

Many countries have passed laws or industry regulations meant to prevent genetic discrimination. However, the real strength of these protections varies. Perceived or actual genetic discrimination continues to deter some patients from seeking testing despite these measures.

The Pathway Forward: What Could Fix These Barriers

The barriers are numerous, but the authors stress they are not insurmountable. Several concrete steps could help.

1. Falling costs. The price of genetic testing will likely continue to drop, improving accessibility over time.
2. Health economic analyses. Dedicated cost-effectiveness studies will likely be needed to convince governments and health insurers to reimburse both the test itself and the genetic counselling around it.
3. International research collaborations. In the meantime, large collaborations offer testing where costs remain prohibitive. The Global Parkinson's Genetics Program (GP2) is a worldwide research collaboration offering free research genetic testing for PD patients, with a specific aim of involving patients traditionally underrepresented in research. Note that research results differ from clinical results in important ways, and returning them to participants requires specific strategies.
4. Better infrastructure. Standardising genetic testing procedures and expanding laboratory capacity — with higher-throughput assays and faster turnaround times — will improve access.
5. Newer technologies. Adopting emerging methods such as long-read sequencing into clinical pipelines could streamline testing and deliver faster, more accurate results.
6. A growing counselling workforce. The global genetic counselling workforce is expanding and must keep growing to meet demand. Telehealth counselling has been shown to be comparable to in-person counselling for several movement disorder groups, including patients with PD and HD — a practical way to close regional gaps.
7. Educating clinicians. Formal training for movement disorder specialists and neurology trainees in genetic counselling and test selection is needed to prepare the workforce for rising demand.
8. Clinical practice guidelines. Guidelines from movement disorder societies and professional organisations on when and how to test, and how to counsel, will help embed testing into routine care. A recently published consensus guideline on counselling patients about GBA1 variants in PD — including a suggested counselling script — offers exactly this kind of practical guidance.
9. Stronger anti-discrimination protections. Expanding and enforcing regulations against genetic discrimination would reassure patients and clinicians that results will not harm employability or insurability.

What This Means for Patients

If you have a movement disorder, this review carries a clear message: you may be a candidate for genetic testing, and it is reasonable to ask about it. Up to 15% of people with Parkinson's disease — about 1 in 7 — carry a genetic variant worth reporting. In dystonia and other movement disorders, factors such as your age at symptom onset, the pattern of your symptoms and your family history can help your doctor decide.

Genetic testing is not only about diagnosis. It can influence treatment choices (such as planning for deep brain stimulation), determine eligibility for clinical trials of new therapies, inform prognosis, guide family planning, and open access to support services.

If cost or access is a barrier where you live, research programmes and international collaborations may offer free testing. Ask your neurologist whether any such studies are recruiting in your area.

Limitations of This Review

This is a narrative review — an expert summary of existing evidence — and not a new study. It did not collect original patient data or run new experiments. Several points should be kept in mind when interpreting its findings.

• Much of the evidence about clinician and patient attitudes comes from surveys, which capture opinions and recollections rather than measured behaviour, and may not represent all doctors or patients.
• Several key findings come from North American and other high-income settings, so the specific barriers and their size may differ in other regions.
• Data on diagnostic yields come from specific study populations — people who enrolled in ROPAD and PD GENEration — who may not mirror the general movement disorder population.
• The review describes feasibility of large-scale testing programmes, but does not yet provide evidence that testing improves long-term patient outcomes — this remains to be proven as precision therapies are developed. Likewise, the suggested benefits such as earlier diagnosis and better access to precision treatments are expected consequences, not yet demonstrated results.
• Cost figures and availability of tests change rapidly, so some practical details may become outdated.

Practical Recommendations for Patients

1. Ask about genetic testing. If you have Parkinson's disease, dystonia, ataxia or another movement disorder, ask your neurologist whether testing is appropriate for you — and why or why not.
2. Share your family history. Details about relatives with similar symptoms help your doctor judge the likelihood that a genetic cause is present.
3. Request genetic counselling. Before and after testing, counselling helps you understand results and what they mean for your family. If no counsellor is available locally, ask about telehealth options.
4. Discuss the test choice. Ask whether a targeted gene panel, exome sequencing or genome sequencing is planned, and what the expected chance of finding an answer is. Broader testing can be reanalysed later as new genes are discovered.
5. Raise any discrimination worries. If concerns about employment or insurance are stopping you, talk to your clinician about what protections exist in your country.
6. Look into research programmes. Studies such as the Global Parkinson's Genetics Program and national Parkinson's genetics initiatives may provide free testing and counselling.
7. Know that testing is not just diagnostic. It can affect trial eligibility, treatment planning and, in some cases, prognosis — so a negative experience of "no result" still has value.

Frequently Asked Questions

How common is a genetic cause in Parkinson's disease?

Two large studies, ROPAD and PD GENEration, found a reportable genetic variant in up to 15% of people with Parkinson's disease — roughly 1 in 7. ROPAD used a 50-gene panel and found a yield of 14.8%; PD GENEration used a 7-gene panel with counselling and found 13%. These results have led to calls for routine testing.

What are the main barriers to getting genetic testing for a movement disorder?

Reported barriers include cost and limited insurance coverage, unequal access that hits low- and middle-income countries and minority groups hardest, gaps in clinician knowledge, limited access to genetic counselling, and persistent patient and doctor fears about genetic discrimination. These barriers fall unevenly across the world and even within high-income countries.

Does genetic testing change treatment for Parkinson's disease?

No gene-specific Parkinson's treatments are currently approved. However, knowing genetic status can still shape care. For example, a large Italian longitudinal study found that patients with GBA1 variants who had deep brain stimulation of the subthalamic nucleus gained good motor improvement but experienced worsening cognition in the three years afterwards. Testing can also determine eligibility for clinical trials.

Why might genetic testing be suggested before deep brain stimulation surgery?

A large Italian longitudinal study found that Parkinson's patients carrying GBA1 variants who had deep brain stimulation of the subthalamic nucleus still gained good motor benefit, but experienced worsening cognition in the three years afterwards. As a result, some experts propose offering genetic testing before DBS so risks and benefits can be discussed honestly beforehand.

What does genetic counselling involve and is it available?

Counselling helps patients understand what a result means, what it implies for family members, and what choices lie ahead. A survey of International Parkinson and Movement Disorder Society members found more than half reported low or no access to genetic counselling in their region. Telehealth counselling has been shown comparable to in-person counselling for several movement disorder groups, including Parkinson's and Huntington's disease.

Could a genetic test result affect my job or insurance?

Some patients hesitate to be tested because they worry a result could affect their job or ability to get insurance. A survey of American and Asian Parkinson's patients found American patients were more likely to worry about employability and eligibility for health or life insurance. Many countries have laws or regulations against genetic discrimination, but their real strength varies.

If cost or access is a barrier, are there other ways to get tested?

Large international research collaborations offer another route. The ROPAD and PD GENEration projects delivered free, clinically accredited genetic testing and counselling to patients with Parkinson's disease on a massive scale, proving large-scale delivery is possible. The Global Parkinson's Genetics Program offers free research genetic testing, with a specific aim of involving patients traditionally underrepresented in research.

I have Parkinson's disease and my neurologist says genetic testing isn't useful — should I get a second opinion before deep brain stimulation?

A second opinion is reasonable when genetic testing is dismissed as unhelpful. Up to 15% of people with Parkinson's disease carry a reportable genetic variant, and testing can shape care: carriers of GBA1 variants appear to face increased risk of cognitive decline after deep brain stimulation of the subthalamic nucleus, so some experts propose offering testing before that surgery. Testing also determines eligibility for trials of genetic therapies. Clinicians often assume patients do not want testing, yet most do. Diagnostic Detectives Network provides independent expert second opinions.

Source Information

Original article title: Barriers to clinical genetic testing in movement disorders.

Authors: Yeow D, Rudaks LI, Kumar KR.

Publication details: Current Opinion in Neurology, 2025, Volume 38, pages 355–360. DOI: 10.1097/WCO.0000000000001381. Published by Wolters Kluwer Health, Inc. This is an open access article distributed under the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CC BY-NC-ND).

Note: This patient-friendly article is based on peer-reviewed research.