Search

Background: Mutations in leucine-rich repeat kinase 2 gene (LRRK2), particularly the G2019S mutation in exon 41, have been detected in familial and sporadic Parkinson disease (PD) cases., Objectives: To assess the frequency of LRRK2 exon 41 mutations in a series of sporadic PD cases from Europe and to determine the clinical features of LRRK2 mutation carriers., Design: We analyzed European cases of sporadic PD for the presence of LRRK2 exon 41 mutations. These mutations were screened by denaturing high-performance liquid chromatography, and abnormal chromatograph traces were investigated by direct sequencing to determine the exact nature of the variants. Early-onset sporadic PD cases were also screened for parkin mutations. The haplotypes associated with the G2019S mutation were determined. The clinical characteristics of patients carrying LRRK2 mutations were detailed., Setting: French Network for the Study of Parkinson Disease Genetics. Patients Three hundred twenty patients with apparently sporadic PD from Europe., Main Outcome Measures: Results of genetic analyses., Results: We found the G2019S mutation in 6 patients and identified 2 new variants (Y2006H and T2031S) in 1 patient each. Their clinical features were similar to those of typical PD. All G2019S mutation carriers shared a common haplotype., Conclusions: The G2019S mutation is almost as frequent in sporadic cases (1.9%) as in previously reported familial cases (2.9%) in Europe and occurs in the same common founder. We identified 2 novel variants. Although the phenotype of LRRK2 mutation carriers closely resembles that of typical PD, the age at onset was younger (29 years in 1 patient) than previously described, and 3 patients were improved by deep brain stimulation.

Background: Familial adult myoclonic epilepsy (FAME) is defined by autosomal dominant inheritance, adult onset of myoclonus of the extremities, infrequent epileptic seizures, nonprogressive course, abnormality of polyspikes and waves on examination by EEG and photosensitivity, giant somatosensory evoked potentials, enhancement of C reflex, and premyoclonus spike detected by means of the jerk-locked averaging EEG method. These findings were also observed in patients with benign adult familial myoclonic epilepsy (BAFME) and patients with familial cortical tremor. FAME and BAFME have been described only in Japan. The genes responsible for FAME and BAFME were mapped in the same genetic interval in 8q22.3-q24.1, Objective: To study clinical and genetic characteristics of a European family with FAME., Methods: A four-generation European kindred presenting with FAME, including 18 members, is described. Clinical analysis was performed on 15 living subjects and electrophysiologic study on 5 patients. Linkage analysis was performed with fluorescent microsatellites encompassing the FAME/BAFME locus (8q23.3-q24.1)., Results: Ten living and three deceased relatives had the clinical characteristics of FAME. Mean age at onset of the 10 living patients was 41 years (range, 30-60 years). Eight of the 13 affected subjects had generalized tonic-clonic seizures. Electrophysiologic studies confirmed the diagnosis of FAME in the five patients studied. The pattern of inheritance was consistent with an autosomal dominant inheritance. The locus responsible for FAME/BAFME was excluded., Conclusion: Observation of a European family extends the occurrence of familial adult myoclonic epilepsy to non-Japanese patients. Exclusion of linkage of this family to the locus for familial adult myoclonic epilepsy/benign adult familial myoclonic epilepsy established the genetic heterogeneity of this disorder.

A wide variety of mutations in the parkin gene, including exon deletions and duplications, as well as point mutations, result in autosomal recessive early-onset parkinsonism. Interestingly, several of these anomalies were found repeatedly in unrelated patients and may therefore result from recurrent, de novo mutational events or from founder effects. In the present study, haplotype analysis, using 10 microsatellite markers covering a 4.7-cM region known to contain the parkin gene, was performed in 48 families, mostly from European countries, with early-onset autosomal recessive parkinsonism. The patients carried 14 distinct mutations in the parkin gene, and each mutation was detected in more than one family. Our results support the hypothesis that exon rearrangements occurred independently, whereas some point mutations, found in families from different geographic origins, may have been transmitted by a common founder.

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.

Background: Whether Parkinson disease (PD) and dementia with Lewy bodies (DLB) represent 2 distinct nosologic entities or are diverse phenotypes of Lewy body disease is subject to debate., Objectives: To determine the accuracy of the diagnoses of Lewy body disease, PD, and DLB by validating the clinical diagnoses of 6 neurologists with the neuropathologic findings and to identify early predictors of the diagnoses., Methods: Six raters who were unaware of the neuropathologic diagnoses analyzed 105 clinical vignettes corresponding to 29 cases of Lewy body disease (post hoc analysis of 15 patients with PD and 14 with DLB) and 76 patients without PD or DLB whose cases were confirmed through autopsy findings., Main Outcome Measures: Sensitivity and positive predictive value (PPV) were chosen as validity measures and the K statistic as a reliability measure., Results: Interrater reliability for the diagnoses of Lewy body disease and PD was moderate for the first visit and substantial for the last, whereas agreement for diagnosis of DLB was fair for the first visit and slight for the last. Median sensitivity for diagnosis of Lewy body disease was 56.9% for the first visit and 67.2% for the last; median PPV was 60.0% and 77.4%, respectively. Median sensitivity for the diagnosis of PD was 73.3% for the first visit and 80.0% for the last; median PPV was 45.9% and 64.1%, respectively. Median sensitivity for the diagnosis of DLB was 17.8% for the first visit and 28.6% for the last; median PPV was 75.0% for the first visit and 55.8% for the last. The raters' results were similar to those of the primary neurologists. Several features differentiated PD from DLB, predicted each disorder, and could be used as clinical pointers., Conclusions: The low PPV with relatively high sensitivity for the diagnosis of PD suggests overdiagnosis. Conversely, the extremely low sensitivity for the diagnosis of DLB suggests underdiagnosis. Although the case mix included in the study may not reflect the frequency of these disorders in practice, limiting the clinical applicability of the validity measures, the raters' results were similar to those of the primary neurologists who were not exposed to such limitations. Overall, our study confirms features suggested to predict these disorders, except for the early presence of postural imbalance, which is not indicative of either disorder.

Dentatorubral-pallidoluysian atrophy (DRPLA) is an autosomal dominant neurodegenerative disorder characterized by a degeneration of cerebellar and pallidal efferents, more frequent in Japan. Isolated cases are also encountered. Patients present with variable combination of signs including myoclonus, ataxia, epilepsy, choreoathetosis and dementia, with onset from childhood to the seventh decade. Clinically, DRPLA may be undistinguishable from other genetic disorders, in particular Huntington's disease or the spinocerebellar ataxias. The genetic basis of the inherited form of DRPLA is an expansion to more than 49 repeats of an unstable trinucleotide (CAG) in the DRPLA gene on the short arm of chromosome 12. We determined the frequency of this mutation in patients with the DRPLA phenotype. One hundred and seventeen patients with cerebellar ataxia, from 94 families and 23 isolated cases, as well as 3 patients from families with undiagnosed autosomal dominant neurodegenerative disorders were investigated for the presence of the expanded sequence. None of the patients carried this mutation. This finding suggests that DRPLA is rare in the French population. The search for the DRPLA mutation is justified in patients with the DRPLA phenotype, however, since genetic counselling is often requested and neither clinical, nor neuropathological examinations permit a definite diagnosis of the underlying disease.