Biological and clinical characteristics of individuals at risk for spinocerebellar ataxia types 1, 2, 3, and 6 in the longitudinal RISCA study: analysis of baseline data.

Background: Spinocerebellar ataxias (SCAs) are autosomal, dominantly inherited, fully penetrant neurodegenerative diseases. Our aim was to study the preclinical stage of the most common SCAs: SCA1, SCA2, SCA3, and SCA6.

Methods: Between Sept 13, 2008, and Dec 1, 2011, offspring or siblings of patients with SCA1, SCA2, SCA3, or SCA6 were enrolled into a prospective, longitudinal observational study at 14 European centres.

Autosomal recessive spastic ataxia of Charlevoix Saguenay (ARSACS): expanding the genetic, clinical and imaging spectrum.

Background: Mutations in SACS, leading to autosomal-recessive spastic ataxia of Charlevoix-Saguenay (ARSACS), have been identified as a frequent cause of recessive early-onset ataxia around the world. Here we aimed to enlarge the spectrum of SACS mutations outside Quebec, to establish the pathogenicity of novel variants, and to expand the clinical and imaging phenotype.

Methods: Sequencing of SACS in 22 patients with unexplained early-onset ataxia, assessment of novel SACS variants in 3.

Video game-based coordinative training improves ataxia in children with degenerative ataxia.

Objective: Degenerative ataxias in children present a rare condition where effective treatments are lacking. Intensive coordinative training based on physiotherapeutic exercises improves degenerative ataxia in adults, but such exercises have drawbacks for children, often including a lack of motivation for high-frequent physiotherapy. Recently developed whole-body controlled video game technology might present a novel treatment strategy for highly interactive and motivational coordinative training for children with degenerative ataxias.

Decreased retinal sensitivity and loss of retinal nerve fibers in multiple system atrophy.

Background And Aim: In a previous study, retinal nerve fiber layer thickness (RNFLT) loss was shown as part of the neurodegenerative process in multiple system atrophy (MSA). Here, we investigate in a larger cohort of MSA patients whether the RNFLT loss translates into respective visual field defects.

Methods: Spectral domain optical coherence tomography was performed in 20 MSA patients (parkinsonian subtype = 12, cerebellar subtype = 8) to quantify peripapillary RNFLT.

Mutation in the AP4B1 gene cause hereditary spastic paraplegia type 47 (SPG47) .

We recently identified a new locus for spastic paraplegia type 47 (SPG47) in a consanguineous Arabic family with two affected siblings with progressive spastic paraparesis,intellectual disability, seizures, periventricular white matter changes and thin corpus callosum. Using exome sequencing, we now identified a novel AP4B1 frameshift mutation (c.664delC) in this family.

Acetazolamide-responsive exercise-induced episodic ataxia associated with a novel homozygous DARS2 mutation.

Background: Leukoencephalopathy with brain stem and spinal cord involvement and brain lactate elevation (LBSL) was recently shown to be caused by mutations in the DARS2 gene, encoding a mitochondrial aspartyl-tRNA synthetase. So far, affected individuals were invariably compound heterozygous for two mutations in DARS2, and drug treatments have remained elusive.

Methods: Prospective 2-year follow-up of the natural history of the main presenting symptoms in a homozygous DARS2 mutation carrier, followed by a 60 day treatment with acetazolamide in two different doses and with two random treatment interruptions.

POLG, but not PEO1, is a frequent cause of cerebellar ataxia in Central Europe.

Nuclear genes, in particular mitochondrial polymerase gamma (POLG) and PEO1, have been increasingly recognized to cause mitochondrial diseases. Both genes assume a complementary role as part of the mitochondrial DNA (mtDNA) replication fork and, accordingly, seem to present with largely overlapping phenotypical spectra. We assessed the frequency and phenotypic spectrum of PEO1 compared to POLG mutations in a cohort of 80 patients with cerebellar ataxia for which common repeat expansion diseases had been excluded.