Haplotypes and gene expression implicate the MAPT region for Parkinson disease: the GenePD Study

BACKGROUND

Microtubule-associated protein tau (MAPT) has been associated with several neurodegenerative disorders including forms of parkinsonism and Parkinson disease (PD). We evaluated the association of the MAPT region with PD in a large cohort of familial PD cases recruited by the GenePD Study. In addition, postmortem brain samples from patients with PD and neurologically normal controls were used to evaluate whether the expression of the 3-repeat and 4-repeat isoforms of MAPT, and neighboring genes Saitohin (STH) and KIAA1267, are altered in PD cerebellum.

METHODS

Twenty-one single-nucleotide polymorphisms (SNPs) in the region of MAPT on chromosome 17q21 were genotyped in the GenePD Study. Single SNPs and haplotypes, including the H1 haplotype, were evaluated for association to PD. Relative quantification of gene expression was performed using real-time RT-PCR.

RESULTS

After adjusting for multiple comparisons, SNP rs1800547 was significantly associated with PD affection. While the H1 haplotype was associated with a significantly increased risk for PD, a novel H1 subhaplotype was identified that predicted a greater increased risk for PD. The expression of 4-repeat MAPT, STH, and KIAA1267 was significantly increased in PD brains relative to controls. No difference in expression was observed for 3-repeat MAPT.

CONCLUSIONS

This study supports a role for MAPT in the pathogenesis of familial and idiopathic Parkinson disease (PD). Interestingly, the results of the gene expression studies suggest that other genes in the vicinity of MAPT, specifically STH and KIAA1267, may also have a role in PD and suggest complex effects for the genes in this region on PD risk.

Herbicide exposure modifies GSTP1 haplotype association to Parkinson onset age: the GenePD Study

BACKGROUND

Polymorphisms in the glutathione S-transferase pi gene (GSTP1), encoding GSTP1-1, a detoxification enzyme, may increase the risk of Parkinson disease (PD) with exposure to pesticides. Using the GenePD Study sample of familial PD cases, we explored whether GSTP1 polymorphisms were associated with the age at onset of PD symptoms and whether that relation was modified by exposure to herbicides.

METHODS

Seven single-nucleotide polymorphisms (SNPs) were genotyped and tested for association with PD onset age in men in three strata: no exposure to herbicides, residential exposure to herbicides, and occupational exposure to herbicides. Haplotypes were similarly evaluated in stratified analyses.

RESULTS

Three SNPs were associated with PD onset age in the group of men occupationally exposed to herbicides. Three additional SNPs had significant trends for the association of PD onset age across the herbicide exposure groups. Haplotype results also provided evidence that the relation between GSTP1 and onset age is modified by herbicide exposure. One haplotype was associated with an approximately 8-years-earlier onset in the occupationally exposed group and a 2.8-years-later onset in the nonexposed group.

CONCLUSIONS

Herbicide exposure may be an effect modifier of the relation between glutathione S-transferase pi gene polymorphisms and onset age in familial PD.

BDNF genetic variants are associated with onset age of familial Parkinson disease: GenePD Study

Brain-derived neurotrophic factor (BDNF) stimulates neuronal growth and protects nigral dopamine neurons in animal models of Parkinson disease (PD). Therefore, BDNF is a candidate gene for PD. The authors investigated five single-nucleotide polymorphisms in 597 cases of familial PD. Homozygosity for the rare allele of the functional BDNF G196A (Val66Met) variant was associated with a 5.3-year older onset age (p = 0.0001). These findings suggest that BDNF may influence PD onset age.

Absence of previously reported variants in the SCNA (G88C and G209A), NR4A2 (T291D and T245G) and the DJ-1 (T497C) genes in familial Parkinson's disease from the GenePD study

Parkinson's disease (PD) is a neurodegenerative disorder in which relatives of the probands are affected approximately 4 times as frequently as relatives of control subjects. Several genes have been implicated as genetic risk factors for PD. We investigated the presence of six reported genetic variations in the SCNA, NR4A2, and DJ-1 genes in 292 cases of familial Parkinson's disease from the GenePD study. None of the variants were found in the GenePD families. Our results suggest that other variants or genes account for the familial risk of PD within the GenePD study.

A haplotype at the PARK3 locus influences onset age for Parkinson's disease: the GenePD study

OBJECTIVE

To identify a haplotype influencing onset age for Parkinson's disease (PD) in the PARK3 region on chromosome 2p13.

METHODS

Single nucleotide polymorphisms (SNP) spanning 2.2 Mb and located in or near potential candidate genes were used to fine map the PARK3 region in 527 patients with familial PD, from 264 families.

RESULTS

TT homozygotes for rs1876487 (G/T) had a 7.4-year younger mean age at onset (p = 0.005) compared to patients with GT and GG genotypes. Furthermore, SNP flanking the sepiapterin reductase (7,8-dihydrobiopterin: NADP+ oxidoreductase) (SPR) gene, rs1876487 (p = 0.02) and rs1150500 (p = 0.04), were associated with younger onset age among persons who did not carry the 174 allele of D2S1394. The SPR gene is implicated in dopamine synthesis. Haplotype analysis of three SNP-rs2421095, rs1876487, rs1561244-revealed an association with onset age (p = 0.023) and a haplotype of A-T-G alleles was associated with younger onset for PD (p = 0.005).

CONCLUSIONS

A haplotype at the PARK3 locus, harboring the SPR gene, is associated with onset age of PD. This may suggest a role for the SPR gene in modifying the age at onset of PD.

Segregation analysis of Parkinson disease revealing evidence for a major causative gene

The role of genetics in Parkinson disease (PD) continues to be an area of considerable interest and controversy. We collected information involving the nuclear families of 948 consecutively ascertained PD index cases from the University of Virginia (UVA) Health System, the University of Medicine and Dentistry of New Jersey-Robert Wood Johnson (RWJ) School of Medicine, and Boston University (BU) School of Medicine. We performed a segregation analysis to assess evidence for the presence of a Mendelian pattern of familial transmission. The proportion of male (60.4%) and female (39.6%) cases, the mean age of onset (57.7 years), and the proportion of affected fathers (4.7%), mothers (6.6%), brothers (2.9%), and sisters (3.2%) were similar across the three sites. While most of the index cases were male, modestly more of the reported affected relatives were female. These analyses support the presence of a rare major Mendelian gene for PD in both the age-of-onset and susceptibility model. The age-of-onset model provides evidence for a gene that influences age-dependent penetrance of PD, influencing age of onset rather than susceptibility. We also found evidence for a Mendelian gene influencing susceptibility to the disease. It is not evident whether these two analyses are modeling the same gene or different genes with different effects on PD. The finding of significant genes influencing penetrance for PD raises the question of whether these may interact with environmental factors or other genes to increase the risk for PD. Such gene environment interactions, involving reduced penetrance in PD, may explain the low concordance rates among monozygotic twins for this disease.

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.

Biochemical analysis of cybrids expressing mitochondrial DNA from Contursi kindred Parkinson's subjects

Complex I activity is reduced in cytoplasmic hybrid (cybrid) cell lines that contain mitochondrial DNA (mtDNA) from sporadic Parkinson's disease (PD) patients. This implies that mtDNA aberration occurs in sporadic PD. To assess the integrity of mtDNA in autosomal dominant PD arising from mutation of the alpha-synuclein gene, we transferred mitochondrial genes from PD-affected members of the Italian-American Contursi kindred to cells previously depleted of their endogenous mtDNA. Unlike cybrid cell lines expressing mtDNA from persons with sporadic or maternally inherited PD, the resultant Contursi cybrid lines did not manifest complex I deficiency, indicating that in Contursi PD mtDNA integrity is relatively preserved. Compared to control cybrids, however, Contursi cybrid lines did show some evidence of oxidative stress. For reasons that are unclear, at least a limited amount of mtDNA damage may nevertheless develop in PD patients with alpha-synuclein mutation.

The tau A0 allele in Parkinson's disease

Parkinson's disease (PD) is primarily an alpha-synucleinopathy, rather than a tauopathy, but there is evidence for an indirect association of tau with the pathogenetic process in PD. We therefore assessed the frequency in PD of the tau A0 allele, a dinucleotide repeat marker that has been associated with a sporadic tauopathy, progressive supranuclear palsy (PSP). We found the A0 allele to comprise 79.2% of 758 alleles from PD patients and 71.2% of 264 control alleles (P = 0.008). We also performed a meta-analysis of three previous reports, two of which failed to produce statistically significant results. Taken together, they also support a PD/A0 allelic association, even after correction for misdiagnosis of PSP as PD (P< 0.001). The A0/A0 genotype frequency in our patients (62.3%) did not differ significantly from that in controls (53.0%, P = 0.062), but the meta-analysis, even after correction for misdiagnosis, showed a significant result, with P = 0.002. The frequency of A0 allele and the A0/A0 genotype were compatible with Hardy-Weinberg equilibrium. The frequency of the A0 allele and the A0/A0 genotype in our patients with familial PD was not significantly greater than in those with sporadic PD. We conclude that the tau protein may play a small role in the pathogenesis of PD and that biochemical characterization of this role may suggest opportunities for PD prophylaxis.

An extended 5'-tau susceptibility haplotype in progressive supranuclear palsy

OBJECTIVE

To confirm the association of an extended 5'-tau haplotype on chromosome 17q with the disease phenotype in clinically ascertained individuals with sporadic progressive supranuclear palsy (PSP).

BACKGROUND

PSP is a neurodegenerative disease with parkinsonian signs accompanied by vertical supranuclear palsy and tau pathologic features. Previously, we documented the complete segregation of an extended 5'-tau haplotype consisting of four single nucleotide polymorphisms (SNP) with the disease phenotype in sporadic PSP. This study was conducted in an independent cohort to confirm these results and to improve the statistical power of the data.

DESIGN AND METHODS

Direct sequencing and restriction enzyme digests were used to analyze four SNP in tau Exons 1, 4A, and 8. These contiguous SNP were used to reconstruct an extended 5'-tau haplotype in 52 affected and 54 age-matched control individuals.

RESULTS

The four SNP formed two homozygous 5'-tau haplotypes (HapA and HapC) or a heterozygous genotype. Fifty-one (98%) patients with PSP had HapA; one (2%) with a later onset was heterozygous; and none had HapC. These PSP haplotype frequencies were different (p < 0.00001) from those of the age-matched control group, in which 18 (33%) people had HapA; 26 (48%) were heterozygous; and 10 (19%) had HapC. The extended 5'-tau haplotype, HapA, had a high sensitivity (98%) and a moderate specificity (67%) as a marker for PSP.

CONCLUSIONS

A 5'-tau susceptibility haplotype may be a sensitive marker for sporadic PSP and a genetic defect in, or closely linked to, tau may contribute to the cause of PSP.

Mitochondrial dysfunction in cybrid lines expressing mitochondrial genes from patients with progressive supranuclear palsy

Progressive supranuclear palsy (PSP) is a neurodegenerative movement disorder of unknown etiology. We hypothesized that mitochondrial DNA (mtDNA) aberration could occur in this disease and contribute to its pathogenesis. To address this we created transmitochondrial cytoplasmic hybrid (cybrid) cell lines expressing mitochondrial genes from persons with PSP. The presence of cybrid mtDNA aberration was screened for by biochemical assay of mitochondrial gene products. Relative to a control cybrid set, complex I activity was reduced in PSP cybrid lines (p<0.005). Antioxidant enzyme activities were elevated in PSP cybrid lines. These data suggest that mtDNA aberration occurs in PSP, causes electron transport chain pathology, and can produce oxidative stress. Further study of mitochondrial dysfunction in PSP may yield insights into why neurodegeneration occurs in this disease.

Application of the Unified Parkinson's Disease Rating Scale in progressive supranuclear palsy: factor analysis of the motor scale

An important criterion in scale validation is the demonstration of a stable factor structure. The Unified Parkinson's Disease Rating Scale (UPDRS) is widely used to assess Parkinson's disease (PD). The reliability and applicability of the motor subscale of the UPDRS (UPDRSm) when applied to patients diagnosed with progressive supranuclear palsy (PSP) is unknown. In a sample of 175 patients with PSP, factor analysis revealed five clinically distinct factors: two independent bradykinesia factors (axial/gait and extremities), one rigidity factor, and two independent tremor factors (rest and action). Two items (posture and rest head tremor) did not reach criteria for factor loadings. There was a high degree of internal consistency. These results suggest that UPDRSm is a reliable and applicable scale for assessing most aspects of PSP function as well as severity measures of five clinical disability domains.

The alpha-synuclein Ala53Thr mutation is not a common cause of familial Parkinson's disease: a study of 230 European cases. European Consortium on Genetic Susceptibility in Parkinson's Disease

We report the results of a screen of 230 European familial index cases of Parkinson's disease for the recently described Ala53Thr mutation in the alpha-synuclein gene in an autosomal dominant Parkinson's disease kindred. No mutations were found from this broad white population, and we therefore conclude that although of great interest, this mutation is a very rare cause of familial Parkinson's disease.

Mutation in the alpha-synuclein gene identified in families with Parkinson's disease

Parkinson's disease (PD) is a common neurodegenerative disorder with a lifetime incidence of approximately 2 percent. A pattern of familial aggregation has been documented for the disorder, and it was recently reported that a PD susceptibility gene in a large Italian kindred is located on the long arm of human chromosome 4. A mutation was identified in the alpha-synuclein gene, which codes for a presynaptic protein thought to be involved in neuronal plasticity, in the Italian kindred and in three unrelated families of Greek origin with autosomal dominant inheritance for the PD phenotype. This finding of a specific molecular alteration associated with PD will facilitate the detailed understanding of the pathophysiology of the disorder.

Mutation in the alpha-synuclein gene identified in families with Parkinson's disease

Parkinson's disease (PD) is a common neurodegenerative disorder with a lifetime incidence of approximately 2 percent. A pattern of familial aggregation has been documented for the disorder, and it was recently reported that a PD susceptibility gene in a large Italian kindred is located on the long arm of human chromosome 4. A mutation was identified in the alpha-synuclein gene, which codes for a presynaptic protein thought to be involved in neuronal plasticity, in the Italian kindred and in three unrelated families of Greek origin with autosomal dominant inheritance for the PD phenotype. This finding of a specific molecular alteration associated with PD will facilitate the detailed understanding of the pathophysiology of the disorder.

Mapping of a gene for Parkinson's disease to chromosome 4q21-q23

Parkinson's disease (PD) is the second most common neurodegenerative disorder after Alzheimer's disease, affecting approximately 1 percent of the population over age 50. Recent studies have confirmed significant familial aggregation of PD and a large number of large multicase families have been documented. Genetic markers on chromosome 4q21-q23 were found to be linked to the PD phenotype in a large kindred with autosomal dominant PD, with a Zmax = 6.00 for marker D4S2380. This finding will facilitate identification of the gene and research on the pathogenesis of PD.

Clinical genetic analysis of Parkinson's disease in the Contursi kindred

We performed a clinical genetic analysis of a kindred originating in the town of Contursi in Salerno province, Italy, in which 60 individuals in 5 generations are known to have had Parkinson's disease (PD). Two previously reported autopsy cases showed typical PD with Lewy bodies. The inheritance pattern is apparently autosomally dominant with a segregation ratio of 40.1% for kindred members aged 50 years and older. The mean age at PD onset is 45.6 years (standard deviation, 13.48; range, 20-85) with a mean course to death of 9.2 years (standard deviation, 4.87; range, 2-20). Otherwise, clinical characteristics of PD in the kindred, including variance in onset age and incidence of tremor and levodopa responsiveness, are similar to those of PD in the community. The presence of tremor tended to be concordant in affected parent-child pairs, but there was no parent-child correlation for age at onset or intrasibship clustering of tremor or onset age. A suggestion of anticipation disappeared after adjustment for age-related ascertainment bias. The findings show that a presumably single mutation can produce a heterogeneous PD phenotype, even among siblings. This is consistent with the hypothesis that PD in the community may in fact be caused by such a mutation, but one producing a lower penetrance and older age at onset than those in this kindred.

Clinical research criteria for the diagnosis of progressive supranuclear palsy (Steele-Richardson-Olszewski syndrome): report of the NINDS-SPSP international workshop

To improve the specificity and sensitivity of the clinical diagnosis of progressive supranuclear palsy (PSP, Steele-Richardson-Olszewski syndrome), the National Institute of Neurological Disorders and Stroke (NINDS) and the Society for PSP, Inc. (SPSP) sponsored an international workshop to develop an accurate and universally accepted set of criteria for this disorder. The NINDS-SPSP criteria, which were formulated from an extensive review of the literature, comparison with other previously published sets of criteria, and the consensus of experts, were validated on a clinical data set from autopsy-confirmed cases of PSP. The criteria specify three degrees of diagnostic certainty: possible PSP, probable PSP, and definite PSP. Possible PSP requires the presence of a gradually progressive disorder with onset at age 40 or later, either vertical supranuclear gaze palsy or both slowing of vertical saccades and prominent postural instability with falls in the first year of onset, as well as no evidence of other diseases that could explain these features. Probable PSP requires vertical supranuclear gaze palsy, prominent postural instability, and falls in the first year of onset, as well as the other features of possible PSP. Definite PSP requires a history of probable or possible PSP and histopathologic evidence of typical PSP. Criteria that support the diagnosis of PSP, and that exclude diseases often confused with PSP, are presented. The criteria for probable PSP are highly specific, making them suitable for therapeutic, analytic epidemiologic, and biologic studies, but not very sensitive. The criteria for possible PSP are substantially sensitive, making them suitable for descriptive epidemiologic studies, but less specific. An appendix provides guidelines for diagnosing and monitoring clinical disability in PSP.

Follow-up study of risk factors in progressive supranuclear palsy

The cause of progressive supranuclear palsy (PSP) is not known and has been little studied. The one previous controlled epidemiologic survey, performed at our center in 1986, found small-town experience and greater educational attainment as PSP risks, but, in retrospect, these results may have been produced by ascertainment bias. Since that time, several anecdotal reports have implicated heredity and various environmental exposures in the cause of some cases of PSP. To clarify the results of the previous study and to evaluate the more recently implicated candidate factors in a controlled fashion, we mailed a validated 69-item questionnaire to 91 personally examined patients with PSP and 104 unmatched controls with other neurologic conditions for which they had been referred to our tertiary neurologic center. We were able to match 75 subjects from each group by year of birth, sex, and race and subjected them to a separate matched-pair analysis. We allowed surrogates to supply any or all of the responses. Questions concerned hydrocarbon, pesticide, and herbicide exposure; urban/rural living; auto repair and other occupations; head trauma; educational attainment; maternal age; and family history of PSP, parkinsonism, dementia, and other neurologic conditions. A statistically significant finding was that patients with PSP were less likely to have completed at least 12 years of school (matched odds ratio = 0.35, 95% CI = 0.12-0.95, p = 0.022; unmatched odds ratio = 0.44, 95% CI = 0.21-0.89, p = 0.020). We hypothesize that this result may be a proxy for poor early-life nutrition or for occupational or residential exposure to an as-yet unsuspected toxin. Future studies should examine these potential risk factors in PSP.

Normal distribution of apolipoprotein E alleles in progressive supranuclear palsy

Apolipoprotein E (Apo E) genotype is a genetic risk factor influencing the development of Alzheimer's disease (AD). Progressive supranuclear palsy (PSP), like AD, is a dementing illness with neurofibrillary tangles. We determined the frequencies of Apo E alleles in 52 PSP patients and 52 age- and gender-matched controls. The distribution of Apo E allele frequencies and genotypes showed no difference between PSP and controls. Apo E allele status does not influence the development of PSP.

Autopsy-proven progressive supranuclear palsy in two siblings

Progressive supranuclear palsy (PSP) is a neurodegenerative disorder that is generally considered to be nonfamilial. We report a brother and sister with clinical and pathologic findings characteristic of PSP. Both developed parkinsonism in the eighth decade of life and within 5 years exhibited severe postural instability, bradykinesia, rigidity, dystonia, dysarthria, dysphagia, urinary incontinence, pseudobulbar palsy, and supranuclear oculomotor dysfunction but no tremor. Neither responded to levodopa and/or carbidopa. Their mother and, possibly, maternal grandfather reportedly suffered from a parkinsonian syndrome. Essential tremor occurred in the siblings' father and in two of the brother's three children. Autopsy in the brother at age 81 years and sister at age 79 years revealed changes typical of PSP with atrophy and neurofibrillary tangles in the globus pallidus, subthalamic nucleus, and rostral tegmental brainstem. No Lewy bodies were present. These cases are the first pair of relatives reported with autopsy confirmation of PSP in both and raise the question of genetic predisposition to PSP.

Psychiatric symptoms in progressive supranuclear palsy

Progressive supranuclear palsy (PSP) is an unusual neurodegenerative disorder that superficially resembles Parkinson's disease (PD). It is characterized by gaze palsy, bulbar signs, parkinsonian signs, and mental changes. While mental changes are a frequent finding, they have, with the exception of dementia, been poorly defined. In this study, 19 patients with PSP were evaluated psychiatrically and compared with 42 patients with PD. Fifty-two percent of the patients had some degree of dementia, as measured by the Mini-Mental State Exam. Eight (42%) of the PSP patients had other psychiatric diagnoses, mostly relatively mild depression or anxiety, though two patients had more severe depression. Six (32%) patients had pathologic laughing or crying, and four of these had a psychiatric diagnosis other than dementia. The PSP patients did not differ from the PD patients on measures of depression or anxiety and did not have a greater rate of formal psychiatric diagnoses. This study confirms previous reports of dementia as a common feature of PSP. It further suggests that psychiatric disturbances, while common, are generally relatively mild, though more serious psychiatric illness may be seen.

Gerstmann-Sträussler-Scheinker disease with mutation at codon 102 and methionine at codon 129 of PRNP in previously unreported patients

We present two patients with Gerstmann-Sträussler-Scheinker disease (GSS), one from a previously undescribed kindred and one from the Canadian branch of a previously reported British kindred. In both patients, GSS is caused by a substitution of thymine for cytosine at codon 102 of the prion protein gene (PRNP). In each patient, we confirmed the clinical diagnosis by neuropathologic examination. The mutation, causing a substitution of leucine for proline at residue 102 (P102L) of the prion protein, has been previously reported in at least 30 other families. In the patients described here, the mutation was in coupling with methionine at PRNP codon 129.

Factors predictive of the need for levodopa therapy in early, untreated Parkinson's disease. The Parkinson Study Group

OBJECTIVE

To identify characteristics of patients with early, untreated Parkinson's disease that are the most important predictors of rapid functional decline.

DESIGN

Prospective observational study of a cohort of 800 patients with early, untreated Parkinson's disease who were involved in a multicenter, randomized, double-blind, controlled clinical trial of selegiline hydrochloride (L-deprenyl) and vitamin E (alpha-tocopherol).

PRIMARY OUTCOME VARIABLE

Time from randomization to the onset of disability that necessitated levodopa therapy (end point), as judged by the enrolling investigator.

METHODS

Stepwise Cox regression was used in combination with clinical judgment to identify the most important independent baseline predictors of the primary end point among a host of variables, including treatment with selegiline and vitamin E, global and specific clinical measures of disease severity, demographic variables, and neuropsychological test results.

RESULTS

In addition to selegiline treatment and global disease severity measures, such as the stage according to the criteria of Hoehn and Yahr, impaired domestic capacity, and the activities of daily living score, the complex of postural instability/gait difficulty and bradykinesia were found to be the factors that were most highly associated with the risk of reaching the end point.

CONCLUSIONS

The findings suggest that patients with Parkinson's disease whose early clinical presentation includes either postural instability/gait difficulty or bradykinesia are at high risk for rapid functional decline.

Pregnancy and movement disorders

The concurrence of pregnancy and movement disorders is an uncommon event in a general neurologic practice. Even at specialized movement disorder referral centers, there is insufficient experience to adequately guide management of pregnancy, except perhaps in the case of WD. The questions posed most urgently by patients regard the safety of medication, an issue on which there is insufficient data, and their ability to care for a child for at least the next decade, an issue that differs by disease and social situation. The author's formulation of efficacy and toxicity suggests that certain medications commonly used in movement disorders should be discontinued before pregnancy, if possible. These medications include neuroleptics, amantadine, diazepam, primidone, selegiline, and reserpine. Pregnancy may unmask a pre-existing potential for chorea (i.e., chorea gravidarum) and frequently has a mild exacerbating effect on symptoms of PD; however, it has little effect on other movement disorders. Severe generalized dystonia would probably interfere with vaginal delivery, but the scant existing data suggest minimal effect of movement disorders on pregnancy, childbirth, and neonatal health.

A clinical genetic study of Parkinson's disease: evidence for dominant transmission

We used a family history questionnaire, semi-structured interview, and personal examination of secondary cases to collect data on the prevalence of Parkinson's disease (PD) in relatives of patients seen consecutively for 1 year and assessed the proportion of secondary cases of PD as a function of pedigree completeness. Survival analysis methods were applied to estimate the lifetime risk and age-at-onset distribution of PD among first-degree relatives of probands. When we considered siblings of probands with affected parents, the cumulative risk increased significantly over siblings of probands without affected parents, suggesting significant familial aggregation in a subset of randomly ascertained families. We further analyzed 80 multicase families with two or more affected individuals. Age-adjusted segregation ratios approaching 0.5 and similar proportions of affected parents and siblings, as well as the distribution of ancestral secondary cases, were compatible with an autosomal dominant mode of inheritance with reduced penetrance in a subset of PD.

The epidemiology of PSP

The age-adjusted prevalence of PSP as measured in central New Jersey is 1.5 cases per million population, about 1% of that of Parkinson's disease. It incidence is 3-4 new cases per million population per year, similar to that of such better-known illnesses as myasthenia gravis, the hereditary ataxias as a group and Tourette syndrome. Median actuarially adjusted survival after symptom onset is 5.9-6.9 years. PSP appears to favor no geographical, racial, ethnic or occupational group, though there is anecdotal evidence for hydrocarbon exposure as a candidate etiologic factor. No familial cases of typical PSP have been proven. The one formal case-control study failed to implicate any particular causal agent and the rural predilection of PD appears to be absent in PSP. Better diagnostic methods, more multi-center organization, additional case-control studies and new etiologic hypotheses are needed in the epidemiological investigation of PSP.

Autosomal dominant parkinsonism with benign course and typical Lewy-body pathology

The few previously reported patients with familial parkinsonism and Lewy-body pathology in the substantia nigra displayed a variety of clinical and pathologic syndromes. We now describe a family with very slowly progressive Parkinson's disease (PD) that has, in most cases, responded poorly to levodopa and includes subjective visual difficult. Four personally confirmed cases--with onset at ages 35, 25, 16, and 16-have occurred in three generations, and four suspicious cases have occurred in three other generations. There has been a trend toward progressively younger age of onset. One autopsied case showed a distribution of cell loss and Lewy bodies typical of PD. The hereditary pattern is most compatible with autosomal dominance. This kindred's illness shows that a presumably single Mendelian dominant gene can cause the clinical and pathologic features of PD, and further extends the clinical spectrum of pathologically typical Lewy-body PD.

Retrospective study of drug response in 87 patients with progressive supranuclear palsy

Progressive supranuclear palsy (PSP) is a progressive neurodegenerative disease that responds poorly to pharmacologic intervention despite its clinical, neurochemical, and pathologic similarity to Parkinson's disease. We reviewed our experience with drugs used in the treatment of patients with PSP who were followed in the Department of Neurology, University of Medicine and Dentistry of New Jersey--Robert Wood Johnson Medical School. Of 136 patients identified, adequate drug-response data were available for 87 (64%). Benefit and adverse effects of therapy were graded on a 4-point scale: 0, none; 1, minimal; 2, moderate; 3, marked. The three most frequently used drugs were amitriptyline (32% of patients benefited), imipramine (28% of patients benefited) and levodopa/carbidopa (Sinemet) (38% of patients benefited). Levodopa/carbidopa, amantadine, selegiline, and amitriptyline gave the best risk/benefit ratios. Monotherapy tended to show more benefit and fewer adverse effects than polypharmacy.

Olfactory testing differentiates between progressive supranuclear palsy and idiopathic Parkinson's disease

Olfactory dysfunction occurs in most patients with idiopathic Parkinson's disease (PD). In this study, we sought to determine whether such dysfunction is also present in progressive supranuclear palsy (PSP), a condition which shares a number of motor symptoms with PD and is commonly misdiagnosed as PD. We administered the University of Pennsylvania Smell Identification Test, a standardized test of odor identification ability, to 21 PSP patients; 17 also received a forced-choice odor detection threshold test. We compared the olfactory test scores to those obtained from PD patients and normal controls matched to the PSP patients on the basis of age, sex, and smoking habits. Overall, the olfactory function of the PSP patients was markedly superior to that of the PD patients and did not differ significantly from that of the normal controls. There was no association in either the PSP or PD patient groups between (1) the olfactory test scores and (2) measures of motor symptom severity, disease stage, and medication usage. These findings demonstrate that patients with PSP and PD differ markedly in their ability to smell and suggest that olfactory testing may be useful in their differential diagnosis.

Dopamine-related personality traits in Parkinson's disease

Studies suggest that Parkinson's disease (PD) is associated with a particular group of personality characteristics. With relative uniformity, PD patients are described as industrious, rigidly moral, stoic, serious, and nonimpulsive. In this controlled study, we used a recently developed personality questionnaire, Cloningers's Tridimensional Personality Questionnaire, to test the hypothesis that these personality traits are behavioural manifestations of damaged dopaminergic pleasure and reward systems. We found significantly less (p < 0.01) of a group of traits called "novelty seeking" in PD patients compared with matched medical controls. Patients with low novelty seeking are described as being reflective, rigid, stoic, slow-tempered, frugal, orderly, and persistent, characteristics similar to those in the clinical description of PD patients. We review evidence supporting the claim that novelty seeking is dopamine-dependent, and suggest that damage to the mesolimbic dopaminergic system causes the described personality profile of PD patients.

The genetics of Parkinson's disease

The possibility of a major contribution of hereditary factors to the cause of Parkinson's disease (PD) is being reconsidered by many. The studies preceding the 1980s presented conflicting evidence and suffered from procedural difficulties. The emergence of the MPTP hypothesis and the failure of three twin studies to document a strong hereditary component in the early 1980s turned attention toward an environmental cause of PD. However more recent descriptions of deficiencies in genetically-coded biochemical functions in PD, more sophisticated clinical family analyses, re-analysis and extension of the twin studies and the emergence of several large autopsy-proven PD kindreds raise the possibility of an important heritable factor in PD.

Upper airway dysfunction in olivopontocerebellar atrophy

We report the findings in a patient known to have olivopontocerebellar atrophy who developed respiratory distress, inspiratory stridor, and maximum inspiratory and expiratory flow volume loops. Treatment with carbidopa-levodopa gave symptomatic relief.

Young-onset Parkinson's disease: a clinical review

Young-onset Parkinson's disease (YOPD) is arbitrarily defined as that which produces initial symptoms between the ages of 21 and 39, inclusive. The special problems and concerns of the patient with YOPD present as much of a challenge and opportunity for the clinician as the disease itself does for the researcher. In contrast to juvenile parkinsonism, which is a heterogeneous group of clinicopathologic entities presenting (also arbitrarily) before age 21, YOPD appears to be the same nosologic entity as older-onset PD. It comprises approximately 5% of referral populations in Western countries and about 10% in Japan. Its annual incidence relative to the population at risk is about 1/10 that of PD at age sixty. YOPD tends to have more gradual progression of parkinsonian signs and symptoms, earlier appearance of levodopa-related dyskinesias and levodopa-dose-related motor fluctuations, and frequent presence of dystonia as an early or presenting sign. Studies conflict with regard to the suspected greater familial frequency and lesser frequency of dementia than in older-onset PD.

A large kindred with autosomal dominant Parkinson's disease

We report two large kindreds with Parkinson's disease (PD) apparently inherited in autosomal dominant fashion. Forty-one persons in four generations have been affected; we have examined 7 of them. The two kindreds originated in a single small town in southern Italy and therefore are probably related. The illness was typical for PD except for early onset at a mean age of 46.5 years and a rapid course that averaged 9.7 years from onset to death. Clinical appearance and response to levodopa were typical for PD. Only one instance of definite nonpenetrance is known. Autopsy of 2 patients in one kindred showed the pathological changes typical of PD with Lewy bodies. Disease duration among affected persons who spent most of their lives in Italy was longer than for their affected US relatives, suggesting that exogenous agents may influence the course of this genetic illness. We conclude that what is probably a single gene without an additional environmental insult can cause the pathological changes typical of PD. Our findings therefore enhance the likelihood of a significant genetic component in the cause of sporadic PD. By identifying a toxic gene product, future molecular genetic studies in our kindred(s) may provide insight into the pathogenesis of sporadic PD.