Aileen Shinaman

Heterozygosity for a mutation in the parkin gene leads to later onset Parkinson disease

Background: The vast majority of the parkin mutations previously identified have been found in individuals with juvenile or early onset PD. Previous screening of later onset PD cohorts has not identified substantial numbers of parkin mutations. Methods: Families with at least two siblings with PD were ascertained to identify genes contributing to PD susceptibility. Screening of the parkin gene, by both quantitative PCR and exon sequencing, was performed in those families with either early onset PD (age onset ≤50 years) or positive lod score with a marker in intron 7 of the parkin gene. Results: A total of 25 different mutations in the parkin gene were identified in 103 individuals from 47 families. Mutations were found in both parkin alleles in 41 of the individuals, whereas a single mutation in only one of the two parkin alleles was observed in 62 individuals. Thirty-five of the subjects (34%) with a parkin mutation had an age at onset of 60 years or above with 30 of these 35 (86%) having a detectable mutation on only one parkin allele. Few significant clinical differences were observed among the individuals with two, one, or no mutated copies of the parkin gene. Conclusion: Mutations in the parkin gene occur among individuals with PD with an older age at onset (≥60 years) who have a positive family history of the disease. In addition, the clinical findings of parkin-positive individuals are remarkably similar to those without mutations.

Significant Linkage of Parkinson Disease to Chromosome 2q36-37

Parkinson disease (PD) is the second most common neurodegenerative disorder, surpassed in frequency only by Alzheimer disease. Elsewhere we have reported linkage to chromosome 2q in a sample of sibling pairs with PD. We have now expanded our sample to include 150 families meeting our strictest diagnostic definition of verified PD. To further delineate the chromosome 2q linkage, we have performed analyses using only those pedigrees with the strongest family history of PD. Linkage analyses in this subset of 65 pedigrees generated a LOD score of 5.1, which was obtained using an autosomal dominant model of disease transmission. This result strongly suggests that variation in a gene on chromosome 2q36-37 contributes to PD susceptibility.

Rasagiline improves quality of life in patients with early Parkinson's disease

The objective of this study was to determine the effects of rasagiline as monotherapy on quality of life (QOL) in patients with early Parkinsons disease (PD). Rasagiline, a potent, second‐generation, irreversible, selective monoamine oxidase B inhibitor improves PD symptoms in patients with early PD. Patients with early untreated PD were randomly assigned to once‐daily rasagiline 1 mg/day, rasagiline 2 mg/day, or placebo in a 6‐month, double‐blind trial (n = 404). At the end of 6 months, patients entered the preplanned, active‐treatment phase in which those receiving 1 mg/day and 2 mg/day of rasagiline continued on their previously assigned dosages and those receiving placebo switched to rasagiline 2 mg/day, while maintaining blinding to treatment assignments. QOL was measured with the Parkinsons Disease Quality of Life questionnaire (PDQUALIF) at 0, 14, 26, and 52 weeks after randomization. Analysis of the change in PDQUALIF scores from baseline to 6 months showed adjusted treatment effects (with 95% confidence interval) favoring rasagiline over placebo of −2.91 units (−5.19, −0.64, P = 0.01) for the 1 mg/day group and −2.74 units (−5.02, −0.45, P = 0.02) for the 2 mg/day. Subscore analysis attributed most of this benefit to the self‐image/sexuality domain. At 12 months (n = 266), with all groups receiving rasagiline for at least 6 months, no significant differences in PDQUALIF scores were seen between groups. Rasagiline improved QOL compared with placebo. This QOL improvement appears to be accounted for primarily by the symptomatic benefit of rasagiline.

A Study of Chorea After Tetrabenazine Withdrawal in Patients With Huntington Disease

Objective: To assess tetrabenazine (TBZ) efficacy by evaluating the change in Huntington disease-associated chorea resulting from TBZ treatment withdrawal. Methods: Thirty patients treated in the long term were randomized to 1 of 3 groups assigned to withdraw from TBZ in a double-blind, staggered fashion during a 5-day period. Results: The chorea scores of subjects withdrawn from TBZ treatment increased by 5.3 units from days 1 to 3, whereas the scores of the group with partial or no withdrawal of TBZ treatment increased by 3.0 units (P = 0.0773). A post hoc analysis of the linear trend was positive for reemergent chorea (P = 0.0486). No serious adverse events were reported after abrupt withdrawal of TBZ treatment. Conclusions: The trend for reemergence of chorea in patients with Huntington disease who were withdrawn from TBZ treatment is consistent with the findings from previous studies, thus showing the effectiveness of TBZ in reducing chorea.

Interrater agreement in the assessment of motor manifestations of Huntington's disease

With prospects improving for experimental therapeutics aimed at postponing the onset of illness in preclinical carriers of the Huntingtons disease (HD) gene, we assessed agreement among experienced clinicians with respect to the motor manifestations of HD, a relevant outcome measure for preventive trials in this population. Seventy‐five clinicians experienced in the evaluation of patients with early HD and six non‐clinicians were shown a videotape compiled from the film archives of the United States–Venezuela Collaborative HD Research Project. Observers were asked to rate a 2–3‐minute segment of the motor examination for each of 17 at‐risk subjects. The rating scale ranged from 0 (normal) to 4 (unequivocal extrapyramidal movement disorder characteristic of HD). As measured by a weighted κ statistic, there was substantial agreement among the 75 clinicians in the judgment of unequivocal motor abnormalities comparing scale ratings of 4 with ratings that were not 4 (weighted κ = 0.67; standard error (SE) = 0.09). Agreement among the non‐clinicians was only fair (weighted κ = 0.28; SE = 0.10). Even under the artificial conditions of a videotape study, experienced clinicians show substantial agreement about the signs that constitute the motor manifestations of illness in subjects at risk for HD. We expect these findings to translate to a similar level of interobserver agreement in the clinical trial setting involving experienced investigators examining live patients.

Fear of health insurance loss among individuals at risk for huntington disease

Genetic testing in Huntington disease, an inherited ultimately fatal neurodegenerative disorder, is infrequent despite wide availability. Factors influencing the decision to pursue testing are largely unknown. We conducted a prospective longitudinal observational study of 1,001 individuals in North America who were at risk for Huntington disease who had not pursued genetic testing prior to enrollment. We evaluated the rationale for remaining untested at baseline, determined the concerns of those who eventually pursued testing, and assessed the populations psychological attributes. We contrasted responses between those who did and did not pursue testing, and between United States and Canadian residents. The principal reasons for remaining untested were comfort with risk and uncertainty and the inability to “undo” knowledge gained. After enrollment, 83 individuals [8.3%] pursued genetic testing. Their greatest concern was losing health insurance, and 41.6% of them [vs. 6.7% of those who did not pursue testing; P < 0.001] reported paying out of pocket for testing or other medical services to conceal their genetic risk from their insurer/employer. Among individuals who were tested, more United States residents [46.1%] than Canadian residents [0.0%; P = 0.02] paid out of pocket for health services or genetic testing. Psychological attributes were similar among individuals who did and did not pursue testing. Individuals at risk for Huntington disease who pursued genetic testing feared losing medical insurance, and many paid out of pocket for medical services. Alleviating the fear of health insurance loss may help those who want to pursue genetic testing for many other conditions. [ClinicalTrials.gov number, NCT0052143].

Mutations in LRRK2 other than G2019S are rare in a north-American based sample of familial Parkinson's didease

A total of 956 individuals with Parkinsons disease (PD) from 430 multiplex PD pedigrees were screened for 12 previously reported, pathogenic LRRK2 mutations: R793M, L1114L, I1371V, R1441C, R1441G, R1441H, Y1699C, M1869T, I2012T, I2020T, G2385R, and IVS31 +3G>A. Previous screening identified the LRRK2 G2019S mutation in 5% of our families. Only 1 of the 12 newly screened mutations, R1441C, was detected in a single family in our patient cohort. These results indicate that, although the G2019S mutation remains the most common mutation identified in familial PD patients, other mutations in LRRK2 are infrequent.

Preempting genetic discrimination and assaults on privacy: report of a symposium.

At a symposium in June, 2002, biomedical researchers, clinicians, legal experts, policymakers, and representatives of the insurance industry and the advocacy community gathered to address issues of genetic privacy and discrimination; and to identify research, legal, and policy gaps needing to be filled. They concluded that over the next decade, as more genetic information becomes available and the public becomes more aware of individual risks, concerns about privacy and discrimination will become increasingly important. Documented cases of genetic discrimination are rare and largely anecdotal, yet individuals with genetic conditions harbor significant fears about discrimination. Current laws enacted to protect individuals from workplace and insurance discrimination offer some measure of protection, but leave many unfilled gaps. Moreover, the use of genetic information in potentially discriminatory ways is not limited to employment and insurability. Existing laws do little to protect people seeking life, disability, or long‐term care insurance. And the courts have used genetic information in a wide variety of cases including paternity, criminal, and tort (personal injury) cases. Genetic information that might jeopardize an individuals right to privacy may also be obtained in the course of research studies, including through the collection of DNA and tissue samples. The insurance industry, State and Federal agencies, and the advocacy community are all making efforts to address some of these gaps through legislation and education of clinicians, the public, and policy makers.