SCA2 and SCA3 mutations in young-onset dopa-responsive parkinsonism

In this study no one of our 85 patients of Serbian origin with young-onset (≤ 45 years) dopa-responsive parkinsonism (YOP), previously proved negative for PARK1 and PARK2 mutations, had either spinocerebellar ataxia type 2 (SCA2) or SCA3 mutation. These data do not prove the significance of these two mutations in either sporadic or familial YOP suggestive of Parkinson's disease.     

Rapsyn mutations in hereditary myasthenia: distinct early- and late-onset phenotypes

Rapsyn mutations in 16 unrelated patients with a congenital/hereditary myasthenic syndrome were identified, and a mutation (N88K) common to each of them was found. Two distinct phenotypes were noted: early and late onset. The former is frequently associated with arthrogryposis multiplex congenita and life-threatening crises. The late-onset phenotype developed in adolescence or adulthood and was initially mistaken for seronegative myasthenia gravis. Recognition of this late-onset phenotype should prevent inappropriate immunotherapy.     

Mutation analysis of the PINK1 gene in Southern Italian patients with early- and late-onset parkinsonism

Mutations in the PINK1 gene represent the second most frequent cause of early-onset Parkinson's disease (EOPD). One or two mutated alleles were also reported in some sporadic or familial patients suffering from late-onset Parkinson's disease (LOPD). We aimed at assessing the frequency of mutations in this gene in our population. We performed a sequence analysis of PINK1 in 115 patients diagnosed with Parkinson's disease (PD) from southern Italy, including 93 sporadic cases with EOPD, 9 familial cases with EOPD, and 13 familial cases with LOPD. Three known homozygous mutations (Q456X, W437X, Q126P), corresponding to a 2.6% of all cases, were found. In particular, one mutation was detected among the sporadic cases (1.0%), one mutation among the familial early-onset patients (11.1%) and one mutation among the familial late-onset patients (7.7%). In addition, we found two heterozygous mutations (E476K, R207Q) among the sporadic patients. Only one mutation (R207Q) had not been previously described. Our results assess the role played by PINK1 in EOPD in southern Italy and illustrate the existence of mutations in this gene also in the late-onset form of the disease.     

Relative contribution of SCA2, SCA3 and SCA17 in Korean patients with parkinsonism and ataxia

We examined the relative significance of SCA2, SCA3 and SCA17 in Koreans patients with parkinsonism and ataxia. We recruited patients with either parkinsonism (n = 524; PD = 386 and MSA = 138) or ataxia (n = 44) as their main clinical feature for two years. These patients were screened for SCA2, SCA3 and SCA17. Six cases carried SCA2; one, SCA3; and eight, SCA17. In SCA2 patients, one patient exhibited MSA-P phenotype, and the other five exhibited ataxia. The single patient with SCA3 showed ataxia. In SCA17 patients, one patient presented ataxia, the other seven patients showed parkinsonism (three PD and four MSA-P). Dopamine transporter (DAT) imaging was performed in a subset of ataxic or parkinsonian SCA2 or SCA17, all of whom showed decreased DAT binding. In Korean population, the mutation frequencies of SCA2 and SCA17 were similar. SCA2 was a more significant cause of ataxia, whereas SCA17 was a more significant cause of parkinsonism. Contribution of SCA3 to parkinsonism was insignificant.     

Preclinical and clinical neural network changes in SCA2 parkinsonism

BackgroundThe pathophysiological changes before the presentation of clinical symptoms in parkinsonism are unclear. In this study, we investigated neural network modulations in persons in the preclinical stage of familial parkinsonism, and how the network interactions change at the clinical stage.MethodsWe performed functional MRI in a family with SCA2 mutation, including 9 asymptomatic carriers and 10 mutation carriers with parkinsonian symptoms. Functional connectivity from the posterior putamen bilaterally and rostral supplementary motor area was used to explore network interactions in the subjects.ResultsBoth the asymptomatic carriers and patients had decreased connectivity within the basal ganglia-thalamus-cortical motor loop compared to controls. The asymptomatic carriers showed extensively increased connectivity compared to controls, including the cortico-cortical motor, cortico-cerebellar, cortico-brainstem, and part of the basal ganglia-thalamus-cortical motor circuits. In contrast, the connectivity of most of these networks was decreased in the patients. These abnormalities were relatively normalized after levodopa administration.ConclusionsIn the preclinical stage of SCA2 parkinsonism, the connectivity of a part of the basal ganglia motor loop is weakened as a consequence of dopaminergic deficits; meanwhile, the connectivity of other large-scale brain networks is strengthened presumably to compensate for the dysfunction of the basal ganglia to maintain brain function in the early stage of dopaminergic deficits. The simultaneous effects of progressive disruption of basal ganglia motor circuits and failure of compensatory mechanisms as dopaminergic dysfunction progresses may contribute to the onset of clinical symptoms.     

SCA2 may present as levodopa-responsive parkinsonism.

Some kindreds with familial parkinsonism exhibit genetic anticipation, suggesting possible involvement of trinucleotide repeat expansion. Recent reports have shown trinucleotide repeat expansions in the spinocerebellar ataxia 2 (SCA2) gene in patients with levodopa-responsive parkinsonism. We tested 136 unrelated patients with familial parkinsonism for SCA2 mutations. Two probands had borderline mutations; the rest were normal. (or=36 is pathogenic). The expanded allele segregated with neurological signs in one kindred. The absence of borderline mutations in the normal population, and the co-segregation of the expanded allele with neurological signs in one kindred suggest that SCA2 mutations may be responsible for a subset of familial parkinsonism.     

Phenotypic differences in early- and late-onset obsessive-compulsive disorder

Early-onset forms of many medical diseases have been associated with specific genetic anomalies. To assess the potential marker value of onset age in obsessive-compulsive disorder (OCD), we examined and compared the phenotypic characteristics of patients with early and later onset. The study sample included 38 children with DSM-IV OCD and 129 adults 19 years of age or older, 77 of whom reported OCD onset prior to age 18 and 52 of whom reported OCD onset at 18 years of age or older. DSM-IV diagnoses were ascertained for all subjects using an amended version of the Diagnostic Interview for Genetic Studies (DIGS). An initial comparison of children and adults with childhood onset revealed several differences, including an earlier onset of clinically significant symptoms without impairment and earlier onset of DSM-IV OCD, a higher frequency of learning disabilities, and fewer obsessions and compulsions among our child patients. For this reason, subsequent analyses included only adult patients with early and later OCD onset. Nonimpairing symptom onset prior to puberty, a relatively aggressive course, and a greater number of obsessions and compulsions unrelated to the amount of time in illness characterized early-onset OCD. Later-onset OCD was characterized by nonimpairing symptom onset during puberty, a static course, and relatively few obsessions and compulsions that were variably related to the amount of time in illness. We conclude that children with OCD and adults with childhood onset differ in their report of clinical characteristics and should be analyzed separately in studies concerning the phenotypic characteristics of OCD. Early- and late-onset forms of OCD appear to be characterized by phenotypic features that have important neurobiologic and perhaps genetic implications.     

Neurotransmitter changes in early- and late-onset alzheimer-type dementia

Arai Heii., Yosuke Ichimiya, Kenji Kosaka, Takashi Noroji and Reiji Iizuka: Neurotransmitter Changes in Early- and Late-onset Alzheimer-type Dementia. Prog. Neuro-Psychophamacol. & Biol. Psychiat. 1992, 16(6):883–890.

1. 1. Neurotransmitter-related markers were examined in Alzheimer-type dementia (ATD) and studied whether or not there is biochemical difference between the early- and late-onset sub-groups.

2. 2. Postmortem brains were obtained from neuropathologically diagnosed ATD patients and control subjects with no clinico-neuropathological findings indicative of neuropsychiatric diseases.

3. 3. Neurochemical data in the early- and late-onset groups were compared to the age-matched younger and older control groups, respectively, and expressed as a percentage of the mean value in the respective controls.

4. 4. Choline acetyltransferase activity and concentrations of serotonin and noradrenaline were more severely depleted in the early-onset ATD group than in the late-onset ATD group.

5. 5. These findings indicative of heterogeneity of ATD patients were discussed from the pathogenetic and therapeutic viewpoints.

Neuropsychological functioning in early- and late-onset obsessive-compulsive disorder

Significant relationships have been noted between age of onset and demographics, clinical characteristics, and cerebral metabolic activity in obsessive-compulsive disorder (OCD). The authors investigated whether patients with early (N=21) and late (N=17) onset OCD differ with respect to neuropsychological functioning. Results revealed that the late onset OCD group obtained poorer scores on measures of executive function and auditory attention than the early onset group. Late onset OCD was also associated with poorer visual memory relative to healthy comparison subjects. These findings suggest that early and late onset OCD may be the result of at least partially differing neurobiological mechanisms.     

Familial aggregation of early- and late-onset Parkinson's disease

The role of heredity in early- versus late-onset Parkinson's disease (PD) is controversial. We estimated the degree of increased risk of PD in first-degree relatives of 221 PD probands with age of onset 50 years or younger and 266 PD probands with age of onset older than 50 years compared with the first-degree relatives of 409 control probands. Risk of PD was similar among first-degree relatives of early-onset PD probands (risk ratio [RR], 2.9; 95% confidence interval [CI], 1.6-5.0; p = 0.0002) and late-onset PD probands (RR, 2.7; 95% CI, 1.6-4.4; p = 0.0002) when each was compared with first-degree relatives of controls. However, siblings of early-onset PD probands were at markedly increased risk of PD compared with siblings of controls (RR, 7.9; 95% CI, 2.5-25.5; p = 0.0005), whereas parents of early-onset PD probands were not at significantly increased risk compared with parents of controls (RR, 1.7; 95% CI, 0.9-3.3; p = 0.2). In late-onset families, both siblings (RR, 3.6; 95% CI, 1.3-10.3; p = 0.02) and parents (RR, 2.5; 95% CI, 1.4-4.6; p = 0.003) were at increased risk compared with control relatives. This pattern is consistent with an autosomal recessive contribution to the inheritance of early but not late-onset PD. Genetic factors are important in both early- and late-onset PD, but specific genes and mode of inheritance may differ between the two groups.     

Neuropsychologic features of early- and late-onset Alzheimer's disease

Forty-one patients with clinically diagnosed Alzheimer's disease were divided into two groups for comparison of neuropsychologic features in those with early- and late-onset disease. Handedness was also assessed in all patients. Twenty-three patients with onset before age 65 had significantly more language impairment, whereas 18 patients with onset at age 65 or older had more difficulty with visuoconstructional function. Memory was severely impaired in all patients. Only one patient in each group was left-handed, and the same results were obtained when these were excluded. These observations support the notion of left hemisphere vulnerability in early-onset Alzheimer's disease and can be interpreted as demonstrating the clinical variability of the illness rather than the necessity of dividing it into two distinct entities.     

Autosomal dominant dopa-responsive parkinsonism in a multigenerational Swiss family

AIM: To describe a large family with autosomal dominant parkinsonism. BACKGROUND: Seven genes are directly implicated in autosomally inherited parkinsonism. However, there are several multigenerational large families known with no identifiable mutation. MATERIAL AND METHODS: Family members were evaluated clinically, by history and chart review. Genetic investigation included SCA2, SCA3, UCHL1, SNCA, LRRK2, PINK1, PRKN, PGRN, FMR1 premutation, and MAPT. The proband underwent brain fluorodopa PET (FD-PET) scan, and one autopsy was available. RESULTS: Eleven patients had a diagnosis of Parkinson's disease (PD), nine women. Mean age of onset was 52 with tremor-predominant dopa-responsive parkinsonism. Disease progression was slow but severe motor fluctuations occurred. One patient required subthalamic nucleus deep-brain stimulation with a good motor outcome. One patient had mental retardation, schizophrenia and became demented, and another patient was demented. Three patients and also two unaffected subjects had mild learning difficulties. All genetic tests yielded negative results. FD-PET showed marked asymmetric striatal tracer uptake deficiency, consistent with PD. Pathological examination demonstrated no Lewy bodies and immunostaining was negative for alpha-synuclein. CONCLUSION: Apart from a younger age of onset and a female predominance, the phenotype was indistinguishable from sporadic tremor-predominant PD, including FD-PET scan results. As known genetic causes of autosomal dominant PD were excluded, this family harbors a novel genetic defect.     

Language dysfunction in early- and late-onset possible Alzheimer's disease

Disproportionate involvement of language has been claimed to be a distinguishing feature of Alzheimer's disease (AD) with onset before age 65. We tested this hypothesis in a group of 133 patients with possible AD by NINCDS criteria. Sixty-one had onset of symptoms prior to age 65; the remaining 72, at 65 or later. The two groups were well matched on overall dementia severity as measured by the Mini-Mental State Exam. Using standardized tests, we did not find any significant differences in the severity of language dysfunction between the two groups, particularly after controlling for greater attention/concentration deficits in the early-onset group. Previous reports of differences in language dysfunction between early- and late-onset AD may have been due to small sample sizes and nonstandardized testing.     

Cognitive differences between early- and late-onset Alzheimer's disease

Although neuropathologic studies showed that early-onset Alzheimer's disease (EAD) and "senile dementia" were indistinguishable, clinical studies suggested that EAD and late-onset Alzheimer's disease (LAD) were cognitively distinct. We sought to investigate whether EAD and LAD are cognitively different by comparing patients at the extremes of the ages of onset in order to maximize features that might separate them. We compared 44 men with EAD (age of onset less than 65 years) with 44 men with LAD (age of onset 84 years or older) on an intake cognitive screening examination on initial presentation. The EAD and LAD groups did not differ on dementia or most cognitive variables. Compared with EAD, the LAD group had worse verbal fluency and motor-executive functions. These differences disappeared when age differences were taken into account. We conclude that Alzheimer's disease is a clinically heterogeneous disorder whose manifestations can vary with age of onset. These differences indicate age-related vulnerabilities in this disease.     

Genetic analysis of the alpha2-macroglobulin gene in early- and late-onset Parkinson's disease

Recent association studies investigating polymorphisms in the alpha2-macroglobulin (A2M) gene provided evidence for an involvement of this protease inhibitor in the pathogenesis of Alzheimer's disease (AD). The partially overlapping pathology between AD and Parkinson's disease (PD) led us to investigate the role of A2M in PD. We performed association studies in a large sample of 328 German PD patients and 322 closely matched healthy controls. Analyzing the Val1000Ile polymorphism and a pentanucleotide deletion in the 5' splice site of exon 18 of the A2M gene we found an excess of homozygosity for the A2M deletion in early-onset PD (EOPD) patients (age at onset < 50 years) compared to late-onset PD (LOPD) patients (age at onset > 50 years; p = 0.008, p(p)c = 0.064, chi2 = 7.017). Therefore our data might indicate an age at onset modulating effect of the homozygous A2M deletion in PD.     

Fingerprint pattern differences in early- and late-onset primary degenerative dementia

The frequency distribution of major fingerprint patterns (ulnar or radial loops, arches, and whorls) was studied in 47 men with early-onset (aged, less than or equal to 64 years), 35 men with late-onset primary degenerative dementia (aged, greater than or equal to 65 years), and 100 control subjects (aged, 29 to 78 years). Patients with an early, but not those with a late, onset of dementia had significantly more ulnar loops than the control group. This finding, along with other data, is interpreted as indicating that there may be a biologic basis for distinguishing these two forms of dementia.