Knowledge and Attitudes Toward Genetic Testing in

Parkinson’s Disease

Dana Lundberg 2006

Parkinson’s Disease

• Is a degenerative neurological disorder

• Affects the substantia nigra, the part of the brain that controls movement

• Includes three symptoms: a resting tremorrigiditybradykinesia (slowness)

Substantia Nigrawww.nlm.nih.gov/medlineplus/

ency/imagepages/19515.htm

• Parkinson’s disease is divided into two onset categories:

Young-onset (less than 50 years at onset)Old-onset (50 years or older at onset)

Onset Categories

Objectives

• To identify attitudes Parkinson’s disease patients have toward diagnostic, predictive, and prenatal genetic testing

• To identify the resources most used by patients for information on Parkinson’s disease

• To assess the level of knowledge patients have about the genetics of Parkinson’s disease

Genetics of Parkinson’s • Studies by Healy et al. (2004), Toft et al. (2005), and

Hattori et al. (2004) revealed several gene mutations

• Genes that mutations have been identified in:- parkin- PINK1- DJ-1- α-Synuclein- LRKK2

• Clinical genetic testing for the parkin and PINK1 genes is available

Rationale•Prior to wide spread use of genetic testing for Parkinson’s

disease researchers need to be aware of:

The interest level in genetic testing

The level of knowledge patients have of genetic testing

Where to target educational programs for genetic testing

• Jacobs et al. showed attitudes toward genetic testing in a young-onset Parkinson’s population:

72% of subjects indicated that they would take a presymptomatic genetic test

57% were interested in the availability of a prenatal genetic test for Parkinson’s

• My study differs:It included both young and old-onset patientsIt included questions regarding sources of information and

knowledge about the genetics of Parkinson’s

Background

Hypothesis

Patients with Parkinson’s disease will respond with a positive attitude toward diagnostic, predictive, and prenatal genetic testing for the disease.

• Struthers Parkinson’s Center (n = 58)• National Parkinson Foundation’s Young-Onset Conference

in Phoenix, AZ (n = 39)

Struthers Parkinson’s Center (Golden Valley, MN)

Young-Onset Parkinson’s Conference (Phoenix, AZ)

Survey Sites

Survey• Demographics• General knowledge about:

Parkinson’s disease genetics genetics of Parkinson’s disease

• Sources of information on Parkinson’s disease• Attitudes toward:

diagnostic genetic testing predictive genetic testing prenatal genetic testing genetic testing at 100%, 90%, and 60% genetic risk

Data Analysis• Data were tabulated in an Excel spreadsheet• Data were analyzed using descriptive and nonlinear

(chi-squared) statistics • P-values were considered significant when p ≤ 0.050

Distribution of Age of Onset

onset < 50 years

onset ≥ 50 years47%53%

Distribution of Gender

MaleFemale

58%42%

Education Levels of Subject Population

High school

Technical training orsome collegeCollege graduate orhigher

19%

16%65%

Distribution of Subjects with Relatives Diagnosed with

Parkinson’s

none≥ 1

79%

21%

0

5

10

15

20

25

30

35

40

45

50

Neurologist

Books/ magazinesLay organizations

Support/ Conference/Edu. programs

InternetNurse

Physical/

Occupational/Speech

Friends/Family

Radio/TV

Primary Care DoctorSources

Number of subjects

< 50 years at onset

≥ 50 years at onset

Sources of InformationP<0.001

0

5

10

15

20

25

30

35

40

45

50

Neurologist

Books/ magazinesLay organizations

Support/ Conference/Edu. programs

InternetNurse

Physical/

Occupational/Speech

Friends/Family

Radio/TV

Primary Care DoctorSources

Number of subjects

< 50 years at onset

≥ 50 years at onset

Sources of InformationP<0.001

0

5

10

15

20

25

30

35

40

45

50

Neurologist

Books/ magazinesLay organizations

Support/ Conference/Edu. programs

InternetNurse

Physical/

Occupational/Speech

Friends/Family

Radio/TV

Primary Care DoctorSources

Number of subjects

< 50 years at onset

≥ 50 years at onset

Sources of InformationP<0.001

0

5

10

15

20

25

30

35

40

45

50

Neurologist

Books/ magazinesLay organizations

Support/ Conference/Edu. programs

InternetNurse

Physical/

Occupational/Speech

Friends/Family

Radio/TV

Primary Care DoctorSources

Number of subjects

< 50 years at onset

≥ 50 years at onset

Sources of Information

P=0.040

Knowledge about Parkinson's and genetics: Number answering correctly (%)

Knowledge Questions:

< 50 years at

onset n (%)

≥ 50 years at onset n (%)

Total (%) p-value

Parkinson's Disease Knowledge Questions:        

Parkinson’s disease is less common in people who smoke. 16 (35%) 10 (20%) 27% p = 0.090

Parkinson’s disease always begins after age 50. 45 (98%) 46 (90%) 94% p = 0.120

Parkinson’s disease is caused by a problem in brain cells that use dopamine. 44 (96%) 44 (86%) 91% p = 0.110

There is a gene therapy treatment that can cure Parkinson’s disease. 45 (98%) 47 (92%) 95% p = 0.210

There is an over-the counter, “natural” treatment that can cure Parkinson’s disease. 46 (100%) 48 (94%) 97% p = 0.090

Specific Genetic Questions:A gene is composed of a group of proteins. 9 (20%) 4 (8%) 13% p = 0.090

Genetic diseases always begin in childhood. 39 (85%) 40 (78%) 81% p = 0.440

It is possible to have an abnormal gene without having symptoms of a disease.

43 (93%)

39 (76%) 85% p = 0.020

The Genetics of Parkinson's Disease Questions:

Parkinson’s disease can be caused by a mutation in a gene called parkin. 16

(35%) 4 (8%) 21% p < 0.001

Scientists have identified genes that are associated with a higher risk of Parkinson’s disease.

30 (65%)

19 (37%) 51% p = 0.005

There is a gene test that can identify who will get Parkinson’s disease. 9 (20%) 16 (31%) 26% p = 0.180

Knowledge about Parkinson's and genetics: Number answering correctly (%)

Knowledge Questions:

< 50 years at

onset n (%)

≥ 50 years at onset n (%)

Total (%) p-value

Parkinson's Disease Knowledge Questions:        

Parkinson’s disease is less common in people who smoke. 16 (35%) 10 (20%) 27% p = 0.090

Parkinson’s disease always begins after age 50. 45 (98%) 46 (90%) 94% p = 0.120

Parkinson’s disease is caused by a problem in brain cells that use dopamine. 44 (96%) 44 (86%) 91% p = 0.110

There is a gene therapy treatment that can cure Parkinson’s disease. 45 (98%) 47 (92%) 95% p = 0.210

There is an over-the counter, “natural” treatment that can cure Parkinson’s disease. 46 (100%) 48 (94%) 97% p = 0.090

Specific Genetic Questions:A gene is composed of a group of proteins. 9 (20%) 4 (8%) 13% p = 0.090

Genetic diseases always begin in childhood. 39 (85%) 40 (78%) 81% p = 0.440

It is possible to have an abnormal gene without having symptoms of a disease.

43 (93%)

39 (76%) 85% p = 0.020

The Genetics of Parkinson's Disease Questions:

Parkinson’s disease can be caused by a mutation in a gene called parkin. 16

(35%) 4 (8%) 21% p < 0.001

Scientists have identified genes that are associated with a higher risk of Parkinson’s disease.

30 (65%)

19 (37%) 51% p = 0.005

There is a gene test that can identify who will get Parkinson’s disease. 9 (20%) 16 (31%) 26% p = 0.180

Knowledge about Parkinson's and genetics: Number answering correctly (%)

Knowledge Questions:

< 50 years at

onset n (%)

≥ 50 years at onset n (%)

Total (%) p-value

Parkinson's Disease Knowledge Questions:        

Parkinson’s disease is less common in people who smoke. 16 (35%) 10 (20%) 27% p = 0.090

Parkinson’s disease always begins after age 50. 45 (98%) 46 (90%) 94% p = 0.120

Parkinson’s disease is caused by a problem in brain cells that use dopamine. 44 (96%) 44 (86%) 91% p = 0.110

There is a gene therapy treatment that can cure Parkinson’s disease. 45 (98%) 47 (92%) 95% p = 0.210

There is an over-the counter, “natural” treatment that can cure Parkinson’s disease. 46 (100%) 48 (94%) 97% p = 0.090

Specific Genetic Questions:A gene is composed of a group of proteins. 9 (20%) 4 (8%) 13% p = 0.090

Genetic diseases always begin in childhood. 39 (85%) 40 (78%) 81% p = 0.440

It is possible to have an abnormal gene without having symptoms of a disease.

43 (93%)

39 (76%) 85% p = 0.020

The Genetics of Parkinson's Disease Questions:

Parkinson’s disease can be caused by a mutation in a gene called parkin. 16

(35%) 4 (8%) 21% p < 0.001

Scientists have identified genes that are associated with a higher risk of Parkinson’s disease.

30 (65%)

19 (37%) 51% p = 0.005

There is a gene test that can identify who will get Parkinson’s disease. 9 (20%) 16 (31%) 26% p = 0.180

Attitudes toward Genetic Testing: Number answering "yes" (%)

Questions

< 50 years at onset

n (%)

≥ 50 years at onset

n (%)Total

(%) p-value

Diagnostic Genetic Testing: Would you take this test?        

100% genetic risk 33 (72%) 44 (86%) 79% p = 0.250

90% genetic risk 33 (72%) 41 (80%) 76% p = 0.250

60% genetic risk 23 (50%) 34 (67%) 59% p = 0.100

Predictive Genetic Testing: Do you think this genetic test should be offered to people without symptoms of Parkinson’s disease?        

100% genetic risk 36 (78%) 34 (67%) 72% p = 0.250

90% genetic risk 32 (70%) 25 (49%) 59% p = 0.050

60% genetic risk 26 (57%) 25 (49%) 53% p = 0.500

Prenatal Genetic Testing: Do you think a prenatal genetic test should be offered to pregnant mothers?        

100% genetic risk 23 (50%) 17 (33%) 41% p = 0.100

90% genetic risk 23 (50%) 15 (29%) 39% p = 0.050

60% genetic risk 21 (46%) 13 (25%) 35% p = 0.050

Attitudes toward Genetic Testing: Number answering "yes" (%)

Questions

< 50 years at onset

n (%)

≥ 50 years at onset

n (%)Total

(%) p-value

Diagnostic Genetic Testing: Would you take this test?        

100% genetic risk 33 (72%) 44 (86%) 79% p = 0.250

90% genetic risk 33 (72%) 41 (80%) 76% p = 0.250

60% genetic risk 23 (50%) 34 (67%) 59% p = 0.100

Predictive Genetic Testing: Do you think this genetic test should be offered to people without symptoms of Parkinson’s disease?        

100% genetic risk 36 (78%) 34 (67%) 72% p = 0.250

90% genetic risk 32 (70%) 25 (49%) 59% p = 0.050

60% genetic risk 26 (57%) 25 (49%) 53% p = 0.500

Prenatal Genetic Testing: Do you think a prenatal genetic test should be offered to pregnant mothers?        

100% genetic risk 23 (50%) 17 (33%) 41% p = 0.100

90% genetic risk 23 (50%) 15 (29%) 39% p = 0.050

60% genetic risk 21 (46%) 13 (25%) 35% p = 0.050

Attitudes toward Genetic Testing: Number answering "yes" (%)

Questions

< 50 years at onset

n (%)

≥ 50 years at onset

n (%)Total

(%) p-value

Diagnostic Genetic Testing: Would you take this test?        

100% genetic risk 33 (72%) 44 (86%) 79% p = 0.250

90% genetic risk 33 (72%) 41 (80%) 76% p = 0.250

60% genetic risk 23 (50%) 34 (67%) 59% p = 0.100

Predictive Genetic Testing: Do you think this genetic test should be offered to people without symptoms of Parkinson’s disease?        

100% genetic risk 36 (78%) 34 (67%) 72% p = 0.250

90% genetic risk 32 (70%) 25 (49%) 59% p = 0.050

60% genetic risk 26 (57%) 25 (49%) 53% p = 0.500

Prenatal Genetic Testing: Do you think a prenatal genetic test should be offered to pregnant mothers?        

100% genetic risk 23 (50%) 17 (33%) 41% p = 0.100

90% genetic risk 23 (50%) 15 (29%) 39% p = 0.050

60% genetic risk 21 (46%) 13 (25%) 35% p = 0.050

Discussion Overall the attitudes expressed towards diagnostic,

predictive, and prenatal genetic testing were positive 1. A majority (≥ 50%) of patients expressed positive attitudes

toward diagnostic genetic testing at all three levels of genetic risk

2. Young-onset patients expressed positive attitudes toward predictive genetic testing slightly more, but not significantly more, than old-onset patients at all three levels of genetic risk

3. Young-onset patients expressed positive attitudes toward prenatal genetic testing significantly more than old-onset at the 90% and 60% levels of genetic risk (p = 0.050 for both tests)

Most commonly used source of information was a neurologist

Young-onset subjects used the internet significantly more than old-onset (p < 0.001)

Young-onset subjects used lay organizations and support groups/conferences significantly more than the old-onset subjects (p < 0.001 for both resources) a majority of the young-onset subjects were interviewed at a

National Parkinson Foundation conference

Young-onset subjects were significantly more knowledgeable about the genetics of Parkinson’s (p < 0.001 and p = 0.005)Number of patients that correctly answered questions in both

the young-onset and, especially, the old-onset groups was low

Discussion

Applications• Educational programmers:

What aspects of Parkinson’s and genetics to focus programs

Where to publish information to best educate the Parkinson’s community about genetic testing

• Pharmaceutical companies:What populations to target for genetic testingAt what levels of genetic risk patients may be interested in

taking genetic tests

Future Work

• Larger subject population through a mailed survey

• Redesign survey to include reasons for accepting or rejecting genetic testing

• Conduct at a conference oriented toward old-onset or both onset groups

Acknowledgements• Dr. Martha Nance• Catherine Wielinski • Ms. Fruen• 2005-06 Research Team

Knowledge and Attitudes Toward Genetic Testing in

Parkinson’s Disease

Dana Lundberg 2006