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Background Mutations in the nuclear-encoded mitochondrial DNA polymerase gamma (POLG) can result in a wide spectrum of neurological deficits. A common presentation is progressive ataxia (POLG-A) which includes impaired speech and swallowing. The nature, severity and impact of these deficits in POLG-A is not known. A comprehensive quantitative and qualitative characterization of dysarthria and dysphagia in this recurrent ataxia disorder will assist in diagnostics, provide insights into the underlying pathology, and establish the foundation for future therapy trials. Methods 14 consecutive patients with POLG (9 females, mean age = 50.1 y, SD = 11.2) and 34 healthy controls were enrolled. Comprehensive assessments of motor speech and swallowing function, acoustic analysis of speech, videofluoroscopy and measures of quality of life were conducted. Results The speech profile of individuals with POLG-A was characterized by poor control of pitch and strain-strangled voice quality, reduced rate of speech and longer variable silences between words, and articulatory breakdown including imprecise consonants and vowel distortions. Swallowing deficits included slower initiation of the swallow reflex, poor control of bolus and late epiglottic closure. Speech and swallowing related quality of life was worse than healthy controls. Conclusions The dysarthria and dysphagia profiles in POLG-A are largely symptomatic of impaired timing, indicating a mainly spinocerebellar deficit. Dysarthria and dysphagia contribute to a significant impairment in functional quality of life, and progress distinctly from other POLG-A dysfunctions like ataxia or cognitive impairment. Our assessments establish meaningful patient focused outcome measures that will be suitable for use in natural history studies and clinical trials.

Objective Cerebellar ataxia essentially includes deficient postural control. It remains unclear whether augmented sensory information might help cerebellar patients, as the cerebellum underlies processing of various sensory modalities for postural control. Here, we hypothesized that patients with cerebellar degeneration can still exploit audio‐biofeedback (ABF) of trunk acceleration as a real‐time assistive signal to compensate for deficient postural control. Methods Effects on postural sway during stance were assessed in an ABF intervention group versus a no‐ABF disease control group (23 vs. 17 cerebellar patients) in a clinico‐experimental study. A single‐session ABF paradigm of standing plus short exergaming under ABF was applied. Postural sway with eyes open and eyes closed was quantified prior to ABF, under ABF, and post ABF. Results Postural sway in the eyes closed condition was significantly reduced under ABF. Both benefit of ABF and benefit of vision correlated with the extent of postural sway at baseline, and both types of sensory benefits correlated with each other. Patients with strongest postural sway exhibited reduced postural sway also with eyes open, thus benefitting from both vision and ABF. No changes were observed in the no‐ABF control group. Interpretation Our findings provide proof‐of‐principle evidence that subjects with cerebellar degeneration are still able to integrate additional sensory modalities to compensate for deficient postural control: They can use auditory cues functionally similar to vision in the absence of vision, and additive to vision in the presence of vision (in case of pronounced postural sway). These findings might inform future assistive strategies for cerebellar ataxia.

Summary Endophilin-A, a well-characterized endocytic adaptor essential for synaptic vesicle recycling, has recently been linked to neurodegeneration. We report here that endophilin-A deficiency results in impaired movement, age-dependent ataxia, and neurodegeneration in mice. Transcriptional analysis of endophilin-A mutant mice, complemented by proteomics, highlighted ataxia- and protein-homeostasis-related genes and revealed upregulation of the E3-ubiquitin ligase FBXO32/atrogin-1 and its transcription factor FOXO3A. FBXO32 overexpression triggers apoptosis in cultured cells and neurons but, remarkably, coexpression of endophilin-A rescues it. FBXO32 interacts with all three endophilin-A proteins. Similarly to endophilin-A, FBXO32 tubulates membranes and localizes on clathrin-coated structures. Additionally, FBXO32 and endophilin-A are necessary for autophagosome formation, and both colocalize transiently with autophagosomes. Our results point to a role for endophilin-A proteins in autophagy and protein degradation, processes that are impaired in their absence, potentially contributing to neurodegeneration and ataxia., Graphical Abstract, Highlights • Endophilin-A is needed for autophagosome formation in mammalian neurons and brain • Absence of endophilin-A upregulates the E3-ubiquitin ligase FBXO32 • FBXO32-endophilin-A interaction maintains neuronal health and protein homeostasis • Endophilin-A KO mice show age-dependent ataxia, motor impairments, and neurodegeneration, Regulation of protein homeostasis and autophagy has become a promising line of research in the neurodegeneration field. Murdoch et al. now find that endophilin-A, a key factor in clathrin-mediated endocytosis, regulates protein homeostasis through the Foxo3a-Fbxo32 network.

Human skin fibroblasts were isolated from a 48-year-old patient carrying compound heterozygous mutations (c.610+364G>A and c.1311A>G) in OPA1, responsible for early onset optic atrophy complicated by ataxia and pyramidal signs (Behr syndrome; OMIM #210000). Fibroblasts were reprogrammed using episomal plasmids carrying hOCT4, hSOX2, hKLF4, hL-MYC and hLIN28. The generated transgene-free line iPS-OPA1-BEHR showed no additional genomic aberrations, maintained the disease-relevant mutations, expressed important pluripotency markers and was capable to differentiate into cells of all three germ layers in vitro. The generated iPS-OPA1-BEHR line might be a useful platform to study the pathomechanism of early onset complicated optic atrophy syndromes.

Xeroderma pigmentosum (XP) is a rare autosomal-recessive disease (prevalence of 1:200,000 in whites) characterized by hypersensitivity to ultraviolet (UV) radiation because of faulty DNA repair, leading to early-onset recurrent sunburns with cutaneous hyperpigmentation and a 1000-fold increased likelihood of developing dermal and ocular neoplasias, commonly nonmelanoma skin cancer, followed by melanoma. Seven genes (XP A–G) are known to be involved in the process of nucleotide excision repair of UV-induced DNA defects. XP V is involved in the replication process of damaged DNA. More than 20% of XP patients present with neurologic abnormalities, typically ataxia, hyporeflexia, bulbar symptoms, hearing impairment, and severe mental retardation. These typically develop when the aforementioned skin abnormalities are already present. Patients with neurologic symptoms have an earlier mean onset age of cutaneous symptoms (6 months) compared with patients without neurologic symptoms (2 years). Although patients with neurologic abnormalities usually have a more severe cutaneous phenotype, mean survival is similar in both groups, with only 5% of patients surviving beyond the age of 45. Here, we describe 2 adult siblings of Turkish origin (pedigree shown in Fig. 1) with a complex neurological syndrome, distinct skin lesions, and a homozygous mutation in the XP A gene (c.682C>T; p.R228X).

PURPOSE OF REVIEW: Degenerative ataxias are a heterogeneous group of disorders that are clinically characterized by progressive ataxia. They can be subdivided into three major groups: the acquired ataxias, which are due to exogenous or endogenous nongenetic causes, the hereditary ataxias, and the nonhereditary degenerative ataxias. On the basis of a review of the literature published in 2009 and 2010, this review gives an update of the most recent developments in the field of ataxia. RECENT FINDINGS: Using advanced methods of molecular genetic analysis, novel genes for recessive and dominant ataxias were identified. Recent imaging studies in dominantly inherited spinocerebellar ataxias (SCAs) focussed on the analysis of connectivity in the brain. Novel clinical assessment methods were developed and validated in large patient cohorts. Although a phase 3 trial of idebenone in Friedreich ataxia (FRDA) failed, a smaller phase 2 trial of riluzole in a mixed population of ataxia patients suggested a possible antiataxic action of this compound. SUMMARY: Recent molecular advances underline the diversity of degenerative ataxias. With the progress in the development of clinical assessment methods for ataxia, the methodological requirements to run large interventional trials are now met.

Summary In most patients with adult-onset progressive ataxia, the condition manifests without an obvious familial background. The classification and correct diagnosis of such patients remain a challenge, because almost the entire spectrum of non-genetic and genetic causes of ataxia has to be considered. A wide range of potential causes of acquired ataxia exist, including chronic alcohol use, various other toxic agents, immune-mediated inflammation, vitamin deficiency, chronic leptomeningeal deposition of iron leading to superficial siderosis, and chronic CNS infection. Mutations in single genes can also underlie sporadic ataxia in adults. Finally, patients might have a sporadic degenerative disease, such as multiple system atrophy of cerebellar type or sporadic adult-onset ataxia of unknown aetiology. The definition of clinical criteria and delineation of characteristic MRI features have greatly facilitated the early and correct recognition of sporadic ataxias. In addition, specific serological and genetic markers are available that allow a definite diagnosis in many cases.

We describe two couples of sibs from a southern Italian family affected by epilepsy, myoclonus, mental retardation and slight ataxia. Onset was between 4 and 12 years and the course slowly progressive. The clinical picture suggested the diagnosis of Unverricht–Lundborg disease. Molecular study excluded linkage to EPM1. Other possible causes of progressive myoclonus epilepsy were also excluded.