Identification of a novel SCA14 mutation in a Dutch autosomal dominant cerebellar ataxia family.
ABSTRACT To report a Dutch family with autosomal dominant cerebellar ataxia (ADCA) based on a novel mutation in the PRKCG gene.
The authors studied 13 affected members of the six-generation family. After excluding the known spinocerebellar ataxia (SCA) genes, a combination of the shared haplotype approach, linkage analysis, and genealogic investigations was used. Exons 4 and 5 of the candidate gene, PRKCG, were sequenced.
Affected subjects displayed a relatively uncomplicated, slowly progressive cerebellar syndrome, with a mean age at onset of 40.8 years. A focal dystonia in two subjects with an onset of disease in their early 20s suggests extrapyramidal features in early onset disease. Significant linkage to a locus on chromosome 19q was found, overlapping the SCA-14 region. Based on the recent description of three missense mutations in the PRKCG gene, located within the boundaries of the SCA-14 locus, we sequenced exons 4 and 5 of this gene and detected a novel missense mutation in exon 4, which involves a G-->A transition in nucleotide 353 and results in a glycine-to-aspartic acid substitution at residue 118.
A SCA-14-linked Dutch ADCA family with a novel missense mutation in the PRKCG gene was identified.
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ABSTRACT: Autosomal dominant spinocerebellar ataxias (SCAs) can present with a large variety of noncerebellar symptoms, including movement disorders. In fact, movement disorders are frequent in many of the various SCA subtypes, and they can be the presenting, dominant, or even isolated disease feature. When combined with cerebellar ataxia, the occurrence of a specific movement disorder can provide a clue toward the underlying genotype. There are reasons to believe that for some coexisting movement disorders, the cerebellar pathology itself is the culprit, for example, in the case of cortical myoclonus and perhaps dystonia. However, movement disorders in SCAs are more likely related to extracerebellar pathology, and imaging and neuropathological data indeed show involvement of other parts of the motor system (substantia nigra, striatum, pallidum, motor cortex) in some SCA subtypes. When confronted with a patient with an isolated movement disorder, that is, without ataxia, there is currently no reason to routinely screen for SCA gene mutations, the only exceptions being SCA2 in autosomal dominant parkinsonism (particularly in Asian patients) and SCA17 in the case of a Huntington's disease-like presentation without an HTT mutation.Movement Disorders 03/2011; 26(5):792-800. · 5.63 Impact Factor
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ABSTRACT: Spinocerebellar ataxia type 14 (SCA14) is an autosomal-dominant ataxia caused by point mutations of the Protein Kinase C Gamma gene. In addition to slowly progressive cerebellar ataxia, it is characterised by dystonia and myoclonus. With scant neuropathological data and no detailed neurophysiological examinations little is known on extracerebellar consequences of SCA14 related cerebellar pathology. To this end, we here delineate clinical phenomenology and neurophysiology of four German SCA14 families. Detailed clinical examination including ataxia severity evaluation by means of the Scale for the Assessment and Rating of Ataxia (SARA) was carried out in 9 affected family members (mean age 49.8 years ± 14.4 SD). Motor thresholds (MT), the contralateral silent period (CSP), short interval intracortical inhibition (SICI) and intracortical facilitation (ICF), interhemispheric inhibition (IHI) and short afferent inhibition (SAI) were determined using transcranial magnetic stimulation (TMS). Somatosensory evoked potentials (SEP) of the median nerve, and acoustic and visual evoked potentials (AEP, VEP) were also performed. Most patients reported symptoms since early childhood. There was a positive correlation between age and SARA scores (r = .721, P < 0.05). Patients had cerebellar ataxia, mild dystonia (focal, task-specific or segmental), subtle pyramidal signs and myoclonus. SICI increased with increasing conditioning pulse intensities in healthy controls but not in patients. Other neurophysiological parameters did not differ between groups. SCA14 is a slowly progressive ataxia associated with mild dystonia and myoclonus. Reduced SICI reflects abnormalities of intracortical inhibitory circuits.The Cerebellum 09/2013; · 2.60 Impact Factor
- Movement Disorders 07/2013; · 5.63 Impact Factor