Targeted sequencing of Parkinson's disease loci genes highlights SYT11, FGF20 and other associations

Genome-wide association studies (GWAS) have identified numerous loci associated with Parkinson's disease. The specific genes and variants that drive the associations within the vast majority of these loci are unknown. We aimed to perform a comprehensive analysis of selected genes to determine the potential role of rare and common genetic variants within these loci. We fully sequenced 32 genes from 25 loci previously associated with Parkinson's disease in 2657 patients and 3647 controls from three cohorts. Capture was done using molecular inversion probes targeting the exons, exon-intron boundaries and untranslated regions (UTRs) of the genes of interest, followed by sequencing. Quality control was performed to include only high-quality variants. We examined the role of rare variants (minor allele frequency < 0.01) using optimized sequence Kernel association tests. The association of common variants was estimated using regression models adjusted for age, sex and ethnicity as required in each cohort, followed by a meta-analysis. After Bonferroni correction, we identified a burden of rare variants in SYT11, FGF20 and GCH1 associated with Parkinson's disease. Nominal associations were identified in 21 additional genes. Previous reports suggested that the SYT11 GWAS association is driven by variants in the nearby GBA gene. However, the association of SYT11 was mainly driven by a rare 3' UTR variant (rs945006601) and was independent of GBA variants (P = 5.23 × 10-5 after exclusion of all GBA variant carriers). The association of FGF20 was driven by a rare 5' UTR variant (rs1034608171) located in the promoter region. The previously reported association of GCH1 with Parkinson's disease is driven by rare non-synonymous variants, some of which are known to cause dopamine-responsive dystonia. We also identified two LRRK2 variants, p.Arg793Met and p.Gln1353Lys, in 10 and eight controls, respectively, but not in patients. We identified common variants associated with Parkinson's disease in MAPT, TMEM175, BST1, SNCA and GPNMB, which are all in strong linkage disequilibrium with known GWAS hits in their respective loci. A common coding PM20D1 variant, p.Ile149Val, was nominally associated with reduced risk of Parkinson's disease (odds ratio 0.73, 95% confidence interval 0.60-0.89, P = 1.161 × 10-3). This variant is not in linkage disequilibrium with the top GWAS hits within this locus and may represent a novel association. These results further demonstrate the importance of fine mapping of GWAS loci, and suggest that SYT11, FGF20, and potentially PM20D1, BST1 and GPNMB should be considered for future studies as possible Parkinson's disease-related genes.

Analysis of Heterozygous PRKN Variants and Copy-Number Variations in Parkinson's Disease

BACKGROUND

Biallelic PRKN mutation carriers with Parkinson's disease (PD) typically have an earlier disease onset, slow disease progression, and, often, different neuropathology compared to sporadic PD patients. However, the role of heterozygous PRKN variants in the risk of PD is controversial.

OBJECTIVES

Our aim was to examine the association between heterozygous PRKN variants, including single-nucleotide variants and copy-number variations (CNVs), and PD.

METHODS

We fully sequenced PRKN in 2809 PD patients and 3629 healthy controls, including 1965 late-onset (63.97 ± 7.79 years, 63% men) and 553 early-onset PD patients (43.33 ± 6.59 years, 68% men). PRKN was sequenced using targeted next-generation sequencing with molecular inversion probes. CNVs were identified using a combination of multiplex ligation-dependent probe amplification and ExomeDepth. To examine whether rare heterozygous single-nucleotide variants and CNVs in PRKN are associated with PD risk and onset, we used optimized sequence kernel association tests and regression models.

RESULTS

We did not find any associations between all types of PRKN variants and risk of PD. Pathogenic and likely-pathogenic heterozygous single-nucleotide variants and CNVs were less common among PD patients (1.52%) than among controls (1.8%, false discovery rate-corrected P = 0.55). No associations with age at onset and in stratified analyses were found.

CONCLUSIONS

Heterozygous single-nucleotide variants and CNVs in PRKN are not associated with PD. Molecular inversion probes allow for rapid and cost-effective detection of all types of PRKN variants, which may be useful for pretrial screening and for clinical and basic science studies targeting specifically PRKN patients. © 2020 International Parkinson and Movement Disorder Society.

Analysis of common and rare VPS13C variants in late-onset Parkinson disease

Objective

We aimed to study the role of coding VPS13C variants in a large cohort of patients with late-onset Parkinson disease (PD) (LOPD).

Methods

VPS13C and its untranslated regions were sequenced using targeted next-generation sequencing in 1,567 patients with PD and 1,667 controls from 3 cohorts. Association tests of rare potential homozygous and compound heterozygous variants and burden tests for rare heterozygous variants were performed. Common variants were analyzed using logistic regression adjusted for age and sex in each of the cohorts, followed by a meta-analysis.

Results

No biallelic carriers of rare VPS13C variants were found among patients, and 2 carriers of compound heterozygous variants were found in 2 controls. There was no statistically significant burden of rare (minor allele frequency [MAF] <1%) or very rare (MAF <0.1%) coding VPS13C variants in PD. A VPS13C haplotype including the p.R153H-p.I398I-p.I1132V-p.Q2376Q variants was nominally associated with a reduced risk for PD (meta-analysis of the tagging SNP p.I1132V [odds ratio = 0.48, 95% confidence interval = 0.28–0.82, p = 0.0052]). This haplotype was not in linkage disequilibrium with the known genome-wide association study top hit.

Conclusions

Our results do not support a role for rare heterozygous or biallelic VPS13C variants in LOPD. Additional genetic replication and functional studies are needed to examine the role of the haplotype identified here associated with reduced risk for PD.

Elevated GM3 plasma concentration in idiopathic Parkinson's disease: A lipidomic analysis

Parkinson's disease (PD) is a common neurodegenerative disease whose pathological hallmark is the accumulation of intracellular α-synuclein aggregates in Lewy bodies. Lipid metabolism dysregulation may play a significant role in PD pathogenesis; however, large plasma lipidomic studies in PD are lacking. In the current study, we analyzed the lipidomic profile of plasma obtained from 150 idiopathic PD patients and 100 controls, taken from the 'Spot' study at Columbia University Medical Center in New York. Our mass spectrometry based analytical panel consisted of 520 lipid species from 39 lipid subclasses including all major classes of glycerophospholipids, sphingolipids, glycerolipids and sterols. Each lipid species was analyzed using a logistic regression model. The plasma concentrations of two lipid subclasses, triglycerides and monosialodihexosylganglioside (GM3), were different between PD and control participants. GM3 ganglioside concentration had the most significant difference between PD and controls (1.531±0.037 pmol/μl versus 1.337±0.040 pmol/μl respectively; p-value = 5.96E-04; q-value = 0.048; when normalized to total lipid: p-value = 2.890E-05; q-value = 2.933E-03). Next, we used a collection of 20 GM3 and glucosylceramide (GlcCer) species concentrations normalized to total lipid to perform a ROC curve analysis, and found that these lipids compare favorably with biomarkers reported in previous studies (AUC = 0.742 for males, AUC = 0.644 for females). Our results suggest that higher plasma GM3 levels are associated with PD. GM3 lies in the same glycosphingolipid metabolic pathway as GlcCer, a substrate of the enzyme glucocerebrosidase, which has been associated with PD. These findings are consistent with previous reports implicating lower glucocerebrosidase activity with PD risk.

Optimizing extended-release carbidopa/levodopa in Parkinson disease: Consensus on conversion from standard therapy

Purpose of review:

To help clinicians optimize the conversion of a patient's Parkinson disease pharmacotherapy from immediate-release carbidopa/levodopa (IR CD/LD) to an extended-release formulation (ER CD/LD).

Recent findings:

Eleven movement disorders specialists achieved consensus positions on the modification of trial-based conversion guidelines to suit individual patients in clinical practice.

Summary:

Because the pharmacokinetics of ER CD/LD differ from those of IR CD/LD, modification of dosage and dosing frequency are to be expected. Initial regimens may be based on doubling the patient's preconversion levodopa daily dosage and choosing a division of doses to address the patient's motor complications, e.g., wearing-off (warranting a relatively high ER CD/LD dose, possibly at a lower frequency than for IR CD/LD) or dyskinesia (warranting a relatively low dose, perhaps at an unchanged frequency). Patients should know that the main goal of conversion is a steadier levodopa clinical response, even if dosing frequency is unchanged.

Long-Term Treatment with Extended-Release Carbidopa-Levodopa (IPX066) in Early and Advanced Parkinson's Disease: A 9-Month Open-Label Extension Trial

BACKGROUND AND OBJECTIVE

IPX066 is a multiparticulate extended-release formulation of carbidopa-levodopa, designed to produce prolonged therapeutic levodopa plasma concentrations. This 9-month open-label extension study assessed its long-term safety and clinical utility in early and advanced Parkinson's disease (PD).

METHODS

Participants were enrolled from two phase III IPX066 studies and one open-label phase II study. Early PD patients were titrated to an appropriate dosing regimen while advanced patients started with regimens established in the antecedent studies. Adjustment was allowed throughout the extension. Clinical utility measures included the Unified Parkinson's Disease Rating Scale (UPDRS) and Patient Global Impression (PGI) ratings.

RESULTS

Among 268 early PD patients, 53.4 % reported adverse events (AEs) and 1.1 % (three patients) discontinued due to AEs; the most frequent AEs were nausea (5.6 %) and insomnia (5.6 %). Among 349 advanced patients, 60.2 % reported AEs and 3.7 % (13 patients) discontinued due to AEs; the most frequent AEs were dyskinesia (6.9 %) and fall (6.6 %). At month 9 (or early termination), 78.3 % of early patients were taking IPX066 three times daily (median: 720 mg/day) and 87.7 % of advanced patients were taking IPX066 three or four times daily (median: 1450 mg/day). Adjusting for 70 % bioavailability relative to immediate-release (IR) carbidopa-levodopa, the median dosages correspond to ~500 and ~1015 mg/day of IR levodopa in early and advanced PD, respectively. Based on the plasma profiles previously observed in PD patients, the IPX066 regimens in the extension can be estimated to provide a levodopa Cmax (maximum plasma drug concentration) similar to or lower than that provided by IR regimens during the antecedent trials. UPDRS and PGI findings showed sustained treatment effects throughout the extension.

CONCLUSION

During 9 months of extended use, IPX066 exhibited a safety/tolerability profile consistent with dopaminergic PD therapy.

A randomized clinical trial of high-dosage coenzyme Q10 in early Parkinson disease: no evidence of benefit

IMPORTANCE

Coenzyme Q10 (CoQ10), an antioxidant that supports mitochondrial function, has been shown in preclinical Parkinson disease (PD) models to reduce the loss of dopamine neurons, and was safe and well tolerated in early-phase human studies. A previous phase II study suggested possible clinical benefit.

OBJECTIVE

To examine whether CoQ10 could slow disease progression in early PD.

DESIGN, SETTING, AND PARTICIPANTS

A phase III randomized, placebo-controlled, double-blind clinical trial at 67 North American sites consisting of participants 30 years of age or older who received a diagnosis of PD within 5 years and who had the following inclusion criteria: the presence of a rest tremor, bradykinesia, and rigidity; a modified Hoehn and Yahr stage of 2.5 or less; and no anticipated need for dopaminergic therapy within 3 months. Exclusion criteria included the use of any PD medication within 60 days, the use of any symptomatic PD medication for more than 90 days, atypical or drug-induced parkinsonism, a Unified Parkinson's Disease Rating Scale (UPDRS) rest tremor score of 3 or greater for any limb, a Mini-Mental State Examination score of 25 or less, a history of stroke, the use of certain supplements, and substantial recent exposure to CoQ10. Of 696 participants screened, 78 were found to be ineligible, and 18 declined participation.

INTERVENTIONS

The remaining 600 participants were randomly assigned to receive placebo, 1200 mg/d of CoQ10, or 2400 mg/d of CoQ10; all participants received 1200 IU/d of vitamin E.

MAIN OUTCOMES AND MEASURES

Participants were observed for 16 months or until a disability requiring dopaminergic treatment. The prospectively defined primary outcome measure was the change in total UPDRS score (Parts I-III) from baseline to final visit. The study was powered to detect a 3-point difference between an active treatment and placebo.

RESULTS

The baseline characteristics of the participants were well balanced, the mean age was 62.5 years, 66% of participants were male, and the mean baseline total UPDRS score was 22.7. A total of 267 participants required treatment (94 received placebo, 87 received 1200 mg/d of CoQ10, and 86 received 2400 mg/d of CoQ10), and 65 participants (29 who received placebo, 19 who received 1200 mg/d of CoQ10, and 17 who received 2400 mg/d of CoQ10) withdrew prematurely. Treatments were well tolerated with no safety concerns. The study was terminated after a prespecified futility criterion was reached. At study termination, both active treatment groups showed slight adverse trends relative to placebo. Adjusted mean changes (worsening) in total UPDRS scores from baseline to final visit were 6.9 points (placebo), 7.5 points (1200 mg/d of CoQ10; P = .49 relative to placebo), and 8.0 points (2400 mg/d of CoQ10; P = .21 relative to placebo).

CONCLUSIONS AND RELEVANCE

Coenzyme Q10 was safe and well tolerated in this population, but showed no evidence of clinical benefit.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00740714.

Cognitive and motor function in long-duration PARKIN-associated Parkinson disease

IMPORTANCE

Data on the long-term cognitive outcomes of patients with PARKIN-associated Parkinson disease (PD) are unknown but may be useful when counseling these patients.

OBJECTIVE

Among patients with early-onset PD of long duration, we assessed cognitive and motor performances, comparing homozygotes and compound heterozygotes who carry 2 PARKIN mutations with noncarriers.

DESIGN, SETTING, AND PARTICIPANTS

Cross-sectional study of 44 participants at 17 different movement disorder centers who were in the Consortium on Risk for Early-Onset PD study with a duration of PD greater than the median duration (>14 years): 4 homozygotes and 17 compound heterozygotes (hereafter referred to as carriers) and 23 noncarriers.

MAIN OUTCOMES AND MEASURES

Unified Parkinson Disease Rating Scale Part III (UPDRS-III) and Clinical Dementia Rating scores and neuropsychological performance. Linear regression models were applied to assess the association between PARKIN mutation status and cognitive domain scores and UPDRS-III scores. Models were adjusted for age, education, disease duration, language, and levodopa equivalent daily dose.

RESULTS

Carriers had an earlier age at onset of PD (P < .001) and were younger (P = .004) at time of examination than noncarriers. They performed better than noncarriers on the Mini-Mental State Examination (P = .010) and were more likely to receive lower scores on the Clinical Dementia Rating (P = .003). In multivariate analyses, carriers performed better than noncarriers on the UPDRS-III (P = .02) and on tests of attention (P = .03), memory (P = .03), and visuospatial (P = .02) cognitive domains.

CONCLUSIONS AND RELEVANCE

In cross-sectional analyses, carriers demonstrated better cognitive and motor performance than did noncarriers with long disease duration, suggesting slower disease progression. A longitudinal follow-up study is required to confirm these findings.

Self-report of cognitive impairment and mini-mental state examination performance in PRKN, LRRK2, and GBA carriers with early onset Parkinson's disease

While little is known about risk factors for cognitive impairment in early onset Parkinson disease (EOPD), postmortem studies have shown an association between dementia with Lewy bodies (DLB) and glucocerebrosidase (GBA) mutation. We compared Mini-Mental State Examination (MMSE) performance and self-reported cognitive impairment in 699 EOPD participants genotyped for mutations in parkin (PRKN), leucine-rich repeat kinase-2 (LRRK2), and GBA. Logistic regression was used to assess the association between reported cognitive impairment and MMSE score, as well as between GBA group membership and self-reported impairment and MMSE. GBA carriers reported more impairment, but MMSE performance did not differ among genetic groups. Detailed neuropsychological testing is required to explore the association between cognitive impairment and GBA mutations.

Current strategies in the treatment of Parkinson's disease and a personalized approach to management

Parkinson's disease is a progressive, neurodegenerative disorder affecting millions of people worldwide. Given the aging population, the prevalence of the disease is expected to increase substantially. The mainstay of treatment has been dopamine replacement therapy with carbidopa, levodopa, dopamine agonists, monoamine oxidase type B inhibitors, catechol-O-methyltransferase inhibitors and amantadine. Nonmotor features, such as cognitive impairment, mood disorders, autonomic dysfunction, gastrointestinal and genitourinary dysfunction, have a substantial impact on Parkinson's disease patients and their quality of life. This review will provide an overview on medications currently available for management of both motor and nonmotor symptoms of Parkinson's disease. Focus will be placed on recent and evolving studies evaluating symptomatic and neuroprotective effects of medications, and how such studies may impact the future management of Parkinson's disease.

Motor phenotype of LRRK2 G2019S carriers in early-onset Parkinson disease

OBJECTIVE

To determine the motor phenotype of LRRK2 G2019S mutation carriers. LRRK2 mutation carriers were previously reported to manifest the tremor dominant motor phenotype, which has been associated with slower motor progression and less cognitive impairment compared with the postural instability and gait difficulty (PIGD) phenotype.

DESIGN

Cross-sectional observational study.

SETTING

Thirteen movement disorders centers.

PARTICIPANTS

Nine hundred twenty-five early-onset Parkinson disease cases defined as age at onset younger than 51 years.

MAIN OUTCOME MEASURES

LRRK2 mutation status and Parkinson disease motor phenotype: tremor dominant or PIGD. Demographic information, family history of Parkinson disease, and the Unified Parkinson's Disease Rating Scale score were collected on all participants. DNA samples were genotyped for LRRK2 mutations (G2019S, I2020T, R1441C, and Y1699C). Logistic regression was used to examine associations of G2019S mutation status with motor phenotype adjusting for disease duration, Ashkenazi Jewish ancestry, levodopa dose, and family history of Parkinson disease.

RESULTS

Thirty-four cases (3.7%) (14 previously reported) were G2019S carriers. No other mutations were found. Carriers were more likely to be Ashkenazi Jewish (55.9% vs 11.9%; P < .001) but did not significantly differ in any other demographic or disease characteristics. Carriers had a lower tremor score (P = .03) and were more likely to have a PIGD phenotype (92.3% vs 58.9%; P = .003). The association of the G2019S mutation with PIGD phenotype remained after controlling for disease duration and Ashkenazi Jewish ancestry (odds ratio, 17.7; P < .001).

CONCLUSION

Early-onset Parkinson disease G2019S LRRK2 carriers are more likely to manifest the PIGD phenotype, which may have implications for disease course.

Pharmacologic Options for Treatment of Levodopa-Associated ``Wearing Off''

Levodopa remains the gold standard drug for the treatment of Parkinson's disease, but the combination of disease progression and prolonged treatment can lead to ``wearing-off'' problems in the majority of patients. This constitutes the onset of motor fluctuations which includes nonmotor sensory, psychiatric, and autonomic ``off '' symptoms. There are several pharmacologic options to minimize the ``wearing-off'' phenomenon, including adjustment of levodopa treatment, the use of long-acting dopamine agonists, monoamine oxidase type B inhibition, or catechol-O-methyl-transferase inhibition in combination with levodopa. Dopamine agonists may reduce levodopa requirements. Monoamine oxidase type B inhibition can increase dopamine availability by preventing its metabolism. Similarly catechol-O-methyl-transferase inhibitors can increase the half-life of levodopa and the amount available to cross the blood-brain barrier by preventing its breakdown. The selection of a treatment for the management of ``wearing off'' should consider the relief of symptoms and also the potential adverse effects of adjunctive therapy.

Zydis selegiline reduces off time in Parkinson's disease patients with motor fluctuations: a 3-month, randomized, placebo-controlled study

Zydis selegiline dissolves on contact with saliva and undergoes pregastric absorption. This minimizes first-pass metabolism and provides high plasma concentrations of selegiline. In this study, the efficacy and safety of Zydis selegiline was assessed in Parkinson's disease (PD) patients who were experiencing motor fluctuations with levodopa. Patients were randomly assigned to either drug or placebo in a 2:1 ratio in this double-blind, multicenter trial. Significant reductions in daily off time occurred at 4 to 6 weeks with the 1.25 mg dose (9.9%, P = 0.003) and 10 to 12 weeks with the 2.5 mg dose (13.2%, P < 0.001). The total number of off hours was reduced by 2.2 hours at Week 12 from baseline (compared with 0.6 hours in the placebo group). The average number of dyskinesia-free on hours for the Zydis selegiline patients increased by 1.8 hours at Week 12. There was no change in mean percentage of "Asleep" time throughout the study. No apparent differences were detected in the occurrence of drug-related adverse events between the Zydis selegiline group and placebo-treated groups. Adverse events were consistent with known effects of levodopa therapy. Zydis selegiline safely reduces daily off time when used as adjunctive therapy with levodopa in patients with PD.

Corticobasal Degeneration

Corticobasal degeneration is one of the neurodegenerative tauopathies, which are defined as a group of heterogeneous dementias and movement disorders that are characterized neuropathologically by prominent intracellular accumulations of abnormal filaments formed by the microtubule-associated protein tau. Although there are no curative treatments, symptomatic and supportive management can be helpful. Many new therapies are still under development. However, more needs to be learned about the pathogenesis and molecular biology of this disease before an effective therapy can be developed.

Treatment of advanced stage patients with Parkinson's disease

Most patients with Parkinson's disease (PD) receiving chronic levodopa therapy eventually manifest one or more motor response complications, including 'wearing-off' phenomena and on-off phenomena. Additionally, as the disease progresses, motor, neurologic, and neuropsychiatric complications increase and may include freezing spells, falls, dementia, depression and psychosis. The management of patients with advanced PD presents a special clinical challenge because patients may experience an enhanced sensitivity to small changes in plasma levodopa levels and because they may suffer adverse reactions to antiparkinsonian drugs. Management of advanced PD is directed toward decreasing the dose of the offending drug while raising the dose of alternative drug with the goal of maintaining symptom control. In this article, the spectrum of late complications experienced by patients with advanced PD and their management are discussed.

PARK3 influences age at onset in Parkinson disease: a genome scan in the GenePD study

Parkinson disease (PD) is a late-onset neurodegenerative disorder. The mean age at onset is 61 years, but the disease can range from juvenile cases to cases in the 8th or 9th decade of life. The parkin gene on chromosome 6q and loci on chromosome 1p35-36 and 1p36 are responsible for some cases of autosomal recessive early-onset parkinsonism, but they do not appear to influence susceptibility or variability of age at onset for idiopathic PD. We have performed a genomewide linkage analysis using variance-component methodology to identify genes influencing age at onset of PD in a population of affected relatives (mainly affected sibling pairs) participating in the GenePD study. Four chromosomal loci showed suggestive evidence of linkage: chromosome 2p (maximum multipoint LOD [MaxLOD] = 2.08), chromosome 9q (MaxLOD = 2.00), chromosome 20 (MaxLOD = 1.82), and chromosome 21 (MaxLOD = 2.21). The 2p and 9q locations that we report here have previously been reported as loci influencing PD affection status. Association between PD age at onset and allele 174 of marker D2S1394, located on 2p13, was observed in the GenePD sample (P=.02). This 174 allele is common to the PD haplotype observed in two families that show linkage to PARK3 and have autosomal dominant PD, which suggests that this allele may be in linkage disequilibrium with a mutation influencing PD susceptibility or age at onset of PD.

Epidemiologic study of 203 sibling pairs with Parkinson's disease: the GenePD study

OBJECTIVE

To examine patterns of familial aggregation and factors influencing onset age in a sample of siblings with PD.

METHODS

Sibling pairs (n = 203) with PD were collected as part of the GenePD study. Standardized family history, medical history, and risk factor data were collected and analyzed.

RESULTS

The mean age at onset was 61.4 years and did not differ according to sex, exposure to coffee, alcohol, or pesticides. Head trauma was associated with younger onset (p = 0.03) and multivitamin use with later onset (p = 0.007). Age at onset correlation between sibling pairs was significant (r = 0.56, p = 0.001) and was larger than the correlation in year of onset (r = 0.29). The mean difference in onset age between siblings was 8.7 years (range, 0 to 30 years). Female sex was associated with increased frequency of relatives with PD. The frequency of affected parents (7.0%) and siblings (5.1%) was increased when compared with frequency in spouses (2.0%).

CONCLUSIONS

The greater similarity for age at onset than for year of onset in sibling pairs with PD, together with increased risk for biological relatives over spouses of cases, supports a genetic component for PD. Risk to siblings in this series is increased over that seen in random series of PD cases; however, patients in this sample have similar ages at onset and sex distribution as seen for PD generally. These analyses suggest that factors influencing penetrance are critical to the understanding of this disease.

Genome-wide scan for Parkinson's disease: the GenePD Study

A genome-wide scan for idiopathic PD in a sample of 113 PD-affected sibling pairs is reported. Suggestive evidence for linkage was found for chromosomes 1 (214 cM, lod = 1.20), 9 (136 cM, lod = 1.30), 10 (88 cM, lod = 1.07), and 16 (114 cM, lod = 0.93). The chromosome 9 region overlaps the genes for dopamine beta-hydroxylase and torsion dystonia. Although no strong evidence for linkage was found for any locus, these results may be of value in comparison with similar studies by others.

Advances in managing Parkinson's disease

The medical choices are now more numerous: Dopamine agonists may have value not only for addressing the motor fluctuations of levodopa therapy but also for deferring the use of levodopa. Surgical choices are bolstered by the addition of investigational options such as neuronal transplantation, in addition to options currently approved, such as pallidotomy.

Transdermal dopaminergic D(2) receptor agonist therapy in Parkinson's disease with N-0923 TDS: a double-blind, placebo-controlled study

N-0923 is a non-ergot, dopaminergic D(2) agonist designed to be transdermally available. It has anti-parkinsonian effects when infused intravenously. An adhesive matrix patch was developed to deliver N-0923 transdermally (N-0923 TDS). In this phase II trial, we evaluated the effectiveness of various doses of N-0923 TDS at replacing levodopa. Eighty-five Parkinson's disease (PD) patients were randomized to placebo or one of four doses of N-0923 TDS for 21 days. Change in daily levodopa dose was the primary efficacy measure. Significantly greater reductions in levodopa dose were achieved as compared to placebo for the two highest doses of N-0923 TDS. Patients treated with 33.5 mg and 67 mg N-0923 TDS decreased levodopa use by 26% and 28%, vs. 7% for placebo. N-0923 TDS was safe and well tolerated.

Impaired perception of vocal emotions in Parkinson's disease: influence of speech time processing and executive functioning

Little is known about the underlying dimensions of impaired recognition of emotional prosody that is frequently observed in patients with Parkinson's disease (PD). Because patients with PD also suffer from working memory deficits and impaired time perception, the present study examined the contribution of (a) working memory (frontal executive functioning) and (b) processing of the acoustic parameter speech rate to the perception of emotional prosody in PD. Two acoustic parameters known to be important for emotional classifications (speech duration and pitch variability) were systematically varied in prosodic utterances. Twenty patients with PD and 16 healthy controls (matched for age, sex, and IQ) participated in the study. The findings imply that (1) working memory dysfunctions and perception of emotional prosody are not independent in PD, (2) PD and healthy control subjects perceived vocal emotions categorically along two acoustic manipulation continua, and (3) patients with PD show impairments in processing of speech rate information.

Sexual dysfunction in Parkinson's disease

Sexual dysfunction is seen in a number of neurologic diseases. In this article we review normal human sexual response, some neurologic diseases in which sexual dysfunction is seen, and Parkinson's disease (PD). With PD there is often a reduction in sexual interest and function. The studies documenting these problems are detailed. In addition, we focus on the syndrome of hyper- or aberrant sexual function seen with pharmacotherapy of PD.

Comparative tolerability of the newer generation antiparkinsonian agents

In recent years, the treatment of Parkinson's disease has undergone an immense amount of research, resulting in the development of multiple new medications. This has largely been fuelled by dissatisfaction over the development of motor complications secondary to long term levodopa therapy. Different treatment approaches are applied depending on the stage of Parkinson's disease. In early and mild Parkinson's disease, selegiline offers a limited symptomatic effect. Its neuroprotective effect, although at present theoretical, has questionable clinical relevance. Increased mortality associated with selegiline has been reported, although a meta-analysis of 5 different trials did not support this finding. The newer, non-ergoline dopamine agonists, pramipexole and ropinirole, have undergone extensive studies to evaluate their efficacy as monotherapy in early Parkinson's disease. These newer agonists are ideal initial symptomatic medications, primarily because they delay the onset of levodopa-induced motor fluctuations. Efficacy of the newer dopamine agonists in advanced disease seems to be comparable to that of the older agents, bromocriptine and pergolide. Adverse effects can be reduced by starting the medication at a very low dose and then slowly titrating upward. Catechol-O-methyl transferase (COMT) inhibitors are indicated for the treatment of motor fluctuations in advanced disease, particularly the 'wearing-off' phenomenon. Tolcapone, a peripheral and central COMT inhibitor, appears to be quite effective, producing a 47% reduction in 'off' time. Unfortunately, 3 deaths have been observed, which are presumably secondary to tolcapone therapy. The drug has been withdrawn in many countries, and liver enzyme testing is mandatory in the US. Entacapone, a purely peripheral COMT inhibitor with a lower potency than tolcapone, has also proved to be effective and has not been associated with liver damage, obviating the need for testing.

A multicenter trial of ropinirole as adjunct treatment for Parkinson's disease. Ropinirole Study Group

OBJECTIVE

To evaluate the nonergot dopamine agonist ropinirole as an adjunct to L-dopa in a randomized, double-blind trial in PD patients with motor fluctuations.

BACKGROUND

L-dopa in the treatment of PD is associated with motor fluctuations, dyskinesia, and other adverse effects. The use of dopamine agonists in the treatment of PD delays recourse to L-dopa and thus delays the possibility of adverse effect onset.

METHODS

Ropinirole (n = 95) or placebo (n = 54) was added to L-dopa, and L-dopa was then reduced in a planned manner during the 6-month trial.

RESULTS

A significantly greater number of ropinirole patients were able to achieve a 20% or greater reduction in both L-dopa dose and in percent time spent "off" compared with placebo (35.0% versus 13.0%; p = 0.003). The mean daily L-dopa dose was reduced significantly with ropinirole treatment (242 mg versus 51 mg; p < 0.001) as was the percent awake time spent "off" (11.7% versus 5.1%; p = 0.039). There was no difference in the percent of patients who withdrew because of adverse effects (15.8% on ropinirole versus 16.7% on placebo).

CONCLUSIONS

Ropinirole permits a reduction in L-dopa dose with enhanced clinical benefit for PD patients with motor fluctuations.

Tolcapone in stable Parkinson's disease: efficacy and safety of long-term treatment. Tolcapone Stable Study Group

In this double-blind, placebo-controlled trial, we investigated the effect of the catechol-O-methyltransferase inhibitor tolcapone 100 or 200 mg three times daily on activities of daily living and motor function in 298 patients with parkinsonism receiving levodopa but without motor fluctuations. At 6 months, both dosages of tolcapone produced significant reductions in the Unified Parkinson's Disease Rating Scale scores for activities of daily living (Subscale II) and motor function (Subscale III) and in the total score for Subscales I to III. These improvements were maintained up to the 12-month assessment. At 6 months, both tolcapone groups had changes in levodopa dosage that were significantly different from placebo: the tolcapone groups had decreases in mean total daily dose of levodopa, whereas the placebo group had a mean increase. Tolcapone was well tolerated. The principal adverse events were levodopa-related, but these were generally mild or moderate. Diarrhea was the most frequent nondopaminergic adverse event. Tolcapone appears to be beneficial in the treatment of patients with parkinsonism who have not yet developed motor fluctuations.

Sexuality in women with Parkinson's disease

There is a renewed interest in sexuality in chronic disease states. Whereas there is some literature on male sexuality in Parkinson's disease (PD), no study has been devoted exclusively to women. We compared 27 women who had PD with community controls matched for age and marital status by using the Brief Index of Sexual Functioning in Women. Approximately 50% of both samples were sexually active. The women with PD were more likely to be dissatisfied with the quality of the sexual experiences. There were significant differences in the two groups with respect to anxiety or inhibition, vaginal tightness, and involuntary urination. Preoccupation with health problems interfering with sex and dissatisfaction with body appearance were also more prevalent in parkinsonian women, but not statistically different from controls. The PD patients were less satisfied with their sexual relationships and with their partners, and were more depressed as a group when compared with controls (Beck Depression Inventory of 11.8 vs 6.3). In both groups, age was associated with significant changes in satisfaction and activity. In summary, qualitative differences exist in the sexual experiences of women with PD compared with controls.

Tolcapone in stable Parkinson's disease: efficacy and safety of long-term treatment. The Tolcapone Stable Study Group

In this double-blind, placebo-controlled trial, we investigated the effect of the catechol-O-methyltransferase inhibitor tolcapone 100 or 200 mg three times daily on activities of daily living and motor function in 298 patients with parkinsonism receiving levodopa but without motor fluctuations. At 6 months, both dosages of tolcapone produced significant reductions in the Unified Parkinson's Disease Rating Scale scores for activities of daily living (Subscale II) and motor function (Subscale III) and in the total score for Subscales I to III. These improvements were maintained up to the 12-month assessment. At 6 months, both tolcapone groups had changes in levodopa dosage that were significantly different from placebo: the tolcapone groups had decreases in mean total daily dose of levodopa, whereas the placebo group had a mean increase. Tolcapone was well tolerated. The principal adverse events were levodopa-related, but these were generally mild or moderate. Diarrhea was the most frequent nondopaminergic adverse event. Tolcapone appears to be beneficial in the treatment of patients with parkinsonism who have not yet developed motor fluctuations.

Managing the late complications of Parkinson's disease

Most patients with Parkinson's disease (PD) receiving chronic levodopa therapy eventually manifest one or more motor response complications, including "wearing-off" phenomena and "on-off" phenomena. Additionally, as the disease progresses, motor, neurologic, and neuropsychiatric complications increase and may include freezing spells, falls, dementia, depression, and psychosis. The management of patients with advanced PD presents a special clinical challenge because patients may experience an enhanced sensitivity to small changes in plasma levodopa levels and because they may suffer adverse reactions to antiparkinsonian drugs. Management of advanced PD is directed toward decreasing the dose of the offending drug while raising the dose of an alternative drug, with the goal of maintaining symptom control. In this article, the spectrum of late complications experienced by patients with advanced PD and their management are discussed.

Multicenter, placebo-controlled trial of cabergoline taken once daily in the treatment of Parkinson's disease

Cabergoline is a dopaminergic agonist relatively specific for the D2 receptor and much longer-acting than other dopamine agonists. We conducted a randomized, placebo-controlled, double-blind study of cabergoline in 188 levodopa/carbidopa-treated patients with suboptimally controlled Parkinson's disease (PD). The cabergoline patients had significantly better Activities of Daily Living (p = 0.032) and Motor Examination (p = 0.031) scores at the conclusion of the trial compared with the placebo group. The daily levodopa dose for the cabergoline patients decreased 18% compared with a 3% reduction for the placebo group (p < 0.001). The amount of time in the "on" state increased more in the cabergoline group (p = 0.022). The side-effect was similar to that seen with other dopamine agonists, and cabergoline was generally well tolerated. We conclude that cabergoline is an effective adjunct to levodopa for the treatment of PD.

Ventroposterior medial pallidotomy in patients with advanced Parkinson's disease

In a preliminary study, the effects of ventroposterior medial pallidotomy were evaluated in five patients with advanced Parkinson's disease in whom medical therapy had failed. The mean age was 67.0 +/- 5.6 years, and the mean Hoehn and Yahr stage when "off" was 3.9 +/- 1.3. Three patients received unilateral pallidotomies; two of these received another pallidotomy after 8 weeks. Two other patients received staged bilateral pallidotomies. No significant differences in overall function could be seen before and after the first surgical procedure. All three patients with peak-dose dyskinesias or dystonia had marked contralateral reduction in these symptoms. Ventroposterior medial pallidotomy can ameliorate peak-dose dyskinesias in patients with advanced Parkinson's disease. Overall function improvement is not remarkable.

The frequently low cobalamin levels in dementia usually signify treatable metabolic, neurologic and electrophysiologic abnormalities

Cobalamin levels are frequently low in patients with dementia, but it is unclear if they represent definable deficiency and what the mechanisms are. Therefore, patients being evaluated for dementia who had low cobalamin levels but no obvious evidence of deficiency were studied hematologically, neurologically and with metabolic tests and were re-evaluated after cobalamin treatment. Abnormalities suggestive of or diagnostic for deficiency were documented in most of the 16 demented and nondemented patients. Metabolic results: 50% of patients tested had abnormal deoxyuridine suppression and 44% had increased serum methylmalonic acid and/or homocysteine levels; these test results correlated with each other. Neurologic results: 73% of patients had clinical abnormalities, primarily mild neuropathies, not attributable to other causes, 75% had electroencephalographic abnormalities, 77% had abnormal visual evoked potentials and 33% had abnormal somatosensory potentials. Metabolic and neurologic dysfunction were present together or absent together in all but 2 cases. Cobalamin therapy improved 50-100% of the various types of abnormalities, although it did not improve cognitive function in the 13 demented patients. Food-cobalamin malabsorption was found in 60% of the patients. Despite the absence of megaloblastic anemia and rarity of traditional malabsorption of free cobalamin, low cobalamin levels in demented patients frequently represent mild cobalamin deficiency and are often associated with food-cobalamin malabsorption. Perhaps most importantly, this is accompanied not only by metabolic changes but by evidence of mild neurologic dysfunction. Their frequent reversibility by cobalamin confirms that these defects indeed arise from cobalamin deficiency. Although the long-standing dementia does not improve, treating such patients with cobalamin has other concrete benefits.

Fluoxetine and selegiline--lack of significant interaction

The use of the combination of fluoxetine, an anti-depressant serotonin uptake inhibitor, and selegiline, a monoamine oxidase -B inhibitor, was reviewed in a large population of patients with Parkinson's disease. All records were reviewed from a Parkinson's disease clinic to determine how many patients were treated simultaneously with selegiline and fluoxetine. Patient characteristics, duration and dose of treatment, side effects and reasons for discontinuation were noted. Twenty-three patients received both medications at the same time. No additional side effects were noted with the combination therapy that had not already been reported with each medication alone. No serious side effects were found. In this clinic population, fluoxetine and selegiline were used in combination without major side effects, but further observation is warranted.

Adductor laryngeal breathing dystonia in a patient with lubag (X-linked dystonia-Parkinsonism syndrome)

We report a patient with Lubag (X-linked dystonia-parkinsonism) who presented with severe respiratory stridor from adductor laryngeal breathing dystonia. Emergency tracheostomy was necessary, and subsequent laryngeal injection with botulinum toxin led to worsening aspiration. Botulinum toxin injection for severe lingual dystonia was successful.

Outcomes of pregnancy associated with antiepileptic drugs

OBJECTIVE

To determine whether exposure to antiepileptic drugs during pregnancy is associated with poor fetal outcomes (anomalies and death) and to assess the relative risks with phenobarbital, phenytoin sodium, and carbamazepine.

DESIGN

The design was a prospective case-control cohort study of pregnant women with epilepsy and their offspring. Outcomes were compared with those of a control group of 355 healthy women and their offspring.

SETTING

The obstetrics service at Los Angeles County/University of Southern California Medical Center, Los Angeles, a large, inner-city, teaching hospital.

PATIENTS

Two hundred eleven subjects who were pregnant during the years 1987 through 1990, 174 of whom were delivered of infants, were available for analysis. A control group of 355 healthy women and their offspring from the same hospital were randomly selected from a computerized database.

INTERVENTION

None.

MAIN OUTCOME MEASURE

Anomalies and fetal death were the primary outcome measures.

RESULTS

Offspring of women with epilepsy who were exposed to antiepileptic drugs had a higher rate of fetal death and anomalies than did the control population (P = .001). Abnormal outcomes were associated with the three major antiepileptic drugs (carbamazepine, phenytoin, and phenobarbital). In terms of abnormal outcome (death and anomalies), phenobarbital was associated with the highest relative risk, phenytoin with intermediate relative risk, and carbamazepine with the lowest relative risk (P = .019). Numbers were insufficient for assessment of risk associated with valproic acid.

CONCLUSION

All three major antiepileptic drugs (phenobarbital, phenytoin, and carbamazepine) are associated with an increased risk of fetal death and anomalies. We found phenobarbital to be most associated with poor pregnancy outcome.

Autosomal dominant Lewy body parkinsonism in a four-generation family

We report a family with autosomal dominant parkinsonism. The propositus developed parkinsonism at a relatively young age (45 years) and came to autopsy after a 6-year illness. She had typical features of Parkinson's disease except for an absence of rest tremor, although this was present in other family members. A diagnosis of Lewy body parkinsonism was confirmed by neuropathological examination. Additional pathological features included the presence of cortical Lewy bodies and anti-ubiquitin-positive neurites in the cornu Ammonis 2 and 3 (CA2-3) region of the hippocampus. This kindred is similar both clinically and pathologically to a few previously reported pedigrees, further strengthening recent evidence of a genetic etiology of some forms of Parkinson's disease.

Phenotypic expression of X-linked dystonia-parkinsonism (lubag) in two women

Lubag (X-linked dystonia-parkinsonism) has been considered a sex-linked recessive trait and has been mapped to the pericentromeric region of the X chromosome. We studied a 54-year-old man with lubag and two of his female first cousins. Genetic typing was carried out using X chromosome markers. Fluorodopa PET was performed on the man and one of the women. The man had moderately severe parkinsonism and dystonia. A 61-year-old female first cousin had mild left-sided dystonia and her 54-year-old sister had mild generalized chorea. Genetic typing data revealed that all three inherited an X chromosome with marker alleles strongly associated with lubag. Cytologic analysis did not reveal evidence of X chromosomal deletion. Fluorodopa PET in both the man and one affected cousin revealed reduced striatal uptake rate constants consistent with nigrostriatal involvement. These observations suggest that lubag may be a codominant disorder and that it is possible for women to be affected.

Neuropathology of lubag (x-linked dystonia parkinsonism)

Lubag is an x-linked recessive dystonia parkinsonism that affects Filipino men originating principally from the Panay Island. Linkage analysis has confirmed the mode of inheritance and localized the disease gene to the proximal long arm of the x-chromosome. We studied the brain of a 34 year old Filipino man affected with lubag. He developed truncal dystonia at age 30, which subsequently generalized. With disease progression, he also presented with parkinsonism including, rigidity, bradykinesia, and impaired balance. His symptoms were largely unaffected by medication and, at age 34, he underwent a right cryothalamotomy. He died suddenly 2 days after the procedure. The principal neuropathological findings were neuronal loss and a multifocal mosaic pattern of astrocytosis restricted to the caudate and lateral putamen. Similar findings have been reported in two other men with dystonia--one Filipino and the other non-Filipino. The similar pathology of the two Filipino men suggests that this is the pathology of lubag. Recognition of this pathology in a non-Filipino man suggests that the mutation causing lubag may not be restricted to the Filipino population.

Long-term follow-up of adrenal medullary transplantation for Parkinson's disease

Long-term follow-up of eight patients who underwent stereotactic grafting of adrenal medullary tissue into unilateral or bilateral caudate nuclei is presented. We demonstrate that this procedure can be performed with minimal risk. Our results show little benefit when the group as a whole is analyzed. A subgroup of four patients was identified who responded to the procedure, as evidenced by a reduction in motor scores, reduction in medication requirements, and greater "on" time. Three of these patients continue to accrue benefit after 2 years. No characterization of a responder profile was evident. We conclude that a modest benefit is derived from this procedure that may persist for as long as 2 years. Future clinical studies to evaluate grafting procedures are encouraged.

Side effects of selegiline (Eldepryl)

Selegiline (Eldepryl), recently approved as an adjunct to levodopa-carbidopa (Sinemet), was administered to eight patients with Parkinson's disease in an open-label study. Many side effects were seen pertinent in particular to the elderly patient. Urinary retention was precipitated in two gentlemen. We advise that this medication be used with caution in the parkinsonian patient.

Utilization of Unilateral and Bilateral Stereotactically Placed Adrenomedullary-Striatal Autografts in Parkinsonian Humans: Rationale, Techniques, and Observations

A limited clinical pilot study involving an amalgam of specialized disciplines including neurology, neuropharmacology, neuropsychology, neurosurgery, neuroanesthesia, neuroradiology, surgical pathology, neuropathology, and urological surgery was organized to clarify issues related to patient selection, optimization of grafting materials, design of a safe, effective, standardized, and reproducible surgical technique, and possible modification of clinical patterns. After initial assessment of 82 Parkinsonian patients for periods of 6 to 20 months, 10 (age, 39-68 years) were selected for unilateral or bilateral adrenomedullary autografts to the caudate nucleus with ependymal and cerebrospinal fluid contact, employing image-directed stereotactic methods. Selection was made only after clear definition of clinical pattern and optimization of medication responses. Adrenal glands were harvested by a retroperitoneal approach (mean estimated blood loss &lt; 75 ml). Care was taken to maximize the graft content of medullary tissue. Stereotactic methods afforded standardized, reproducible, precise targeting and transit trajectory with unilateral or bilateral placement of materials within the striatum (tissue volume, 80 mm3) with access to the ventricular fluid of the frontal horn. Considerable variability in satisfactory donor medullary tissue was encountered. One patient did not undergo grafting because of unsatisfactory medullary tissue. No significant surgical complications were noted and all patients were ready for discharge 7 days after surgery. One patient who manifested no apparent clinical change died 6 weeks after bilateral grafting of unrelated causes during a lithotripsy procedure. Postmortem examination disclosed precise graft placement with a paucity of structurally preserved medullary cells. Postoperative observations, including parameters of clinical observation, medication schedules and records, patient and family commentaries, and imaging studies (computed tomograms and single photon emission computed tomograms), have been made for periods from 16 to 20 months. Sustained improvement in preexisting clinical patterns and reduction in drug requirements were observed in 4 of 8 patients. No increased benefit could be ascribed to bilateral graft placement. These observations would indicate a primary role for stereotactic methodology for cerebral graft placement, as it affords a minimally invasive but precise, safe, and reproducible surgical method. In addition, the clinical observations indicate favorable alterations in the established pattern of the disorder, which would justify further cautious exploration of alternate donor sources or refinements of biological graft site manipulations.