Welander distal myopathy is caused by a mutation in the RNA-binding protein TIA1.

OBJECTIVE: A study was undertaken to identify the molecular cause of Welander distal myopathy (WDM), a classic autosomal dominant distal myopathy. METHODS: The genetic linkage was confirmed and defined by microsatellite and single nucleotide polymorphism haplotyping. The whole linked genomic region was sequenced with targeted high-throughput and Sanger sequencing, and coding transcripts were sequenced on the cDNA level. WDM muscle biopsies were studied by Western blotting and immunofluorescence microscopy. Splicing of TIA1 and its target genes in muscle and myoblast cultures was analyzed by reverse transcriptase polymerase chain reaction. Mutant TIA1 was characterized by cell biological studies on HeLa cells, including quantification of stress granules by high content analysis and fluorescence recovery after photobleaching (FRAP) experiments. RESULTS: The linked haplotype at 2p13 was narrowed down to <806 kb. Sequencing by multiple methods revealed only 1 segregating coding mutation, c.1362 G>A (p.E384K) in the RNA-binding protein TIA1, a key component of stress granules. Immunofluorescence microscopy of WDM biopsies showed a focal increase of TIA1 in atrophic and vacuolated fibers. In HeLa cells, mutant TIA1 constructs caused a mild increase in stress granule abundance compared to wild type, and showed slower average fluorescence recovery in FRAP. INTERPRETATION: WDM is caused by mutated TIA1 through a dominant pathomechanism probably involving altered stress granule dynamics.

Intragenic deletion of TRIM32 in compound heterozygotes with sarcotubular myopathy/LGMD2H.

In 2005 the commonality of sarcotubular myopathy (STM) and limb girdle muscular dystrophy type 2H (LGMD2H) was demonstrated, as both are caused by the p D487N missense mutation in TRIM32 originally found in the Manitoba Hutterite population. Recently, three novel homozygous TRIM32 mutations have been described in LGMD patients. Here we describe a three generation Swedish family clinically presenting with limb girdle muscular weakness and histological features of a microvacuolar myopathy. The two index patients were compound heterozygotes for a frameshift mutation in TRIM32 (c.1560delC ) and a 30 kb intragenic deletion, encompassing parts of intron 1 and the entire exon 2 of TRIM32. In these patients, no full-length or truncated TRIM32 could be detected. Interestingly, heterozygous family members carrying only one mutation showed mild clinical symptoms and vacuolar changes in muscle. In our family, the phenotype encompasses additionally a mild demyelinating polyneuropathic syndrome. Thus STM and LGMD2H are the result of loss of function mutations that can be either deletions or missense mutations.

Safety and tolerability of NXY-059 for acute intracerebral hemorrhage: the CHANT Trial.

BACKGROUND AND PURPOSE: NXY-059 is a free radical-trapping neuroprotectant developed for use in acute ischemic stroke. To facilitate prompt administration of treatment, potentially before neuroimaging, we investigated the safety of NXY-059 in patients with intracerebral hemorrhage (ICH). METHODS: We randomized 607 patients within 6 hours of acute ICH to receive 2270 mg intravenous NXY-059 over 1 hour and then up to 960 mg/h over 71 hours, or matching placebo, in addition to standard care. The primary outcome was safety: the mortality and the frequency of adverse events, and the change from baseline for a variety of serum, imaging, and electrophysiological measurements. We also studied the overall distribution of disability scores on the modified Rankin Scale (mRS) and the Barthel index. RESULTS: We treated 300 patients with NXY-059 and 303 with placebo. Treatment groups were well matched for prognostic variables including Glasgow Coma Scale, risk factors, and age. The mean National Institute of Health Stroke Scale score on admission was 14 in both groups. The baseline hemorrhage volume was 22.4+/-20.1 mL in the NXY-059 group and 23.3+/-22.8 mL in the placebo group (mean+/-SD). Most hemorrhages were related to hypertension or anticoagulant use. Mortality was similar in both groups: 20.3% for NXY-059 and 19.8% for placebo-treated patients. The proportion of patients who experienced an adverse event was the same for both groups, whereas for serious adverse events the proportion was slightly higher in the NXY-059 group. However, no pattern emerged to indicate a safety concern. Serum potassium fell transiently in both groups, lower in the NXY-059 group. There were no differences in 3-month function, disability, or neurological deficit scores. The odds ratio for an improved outcome in 3-month mRS scores in the NXY-059 group was 1.01 (95% CI 0.75, 1.35). CONCLUSIONS: NXY-059 given within 6 hours of acute ICH has a good safety and tolerability profile, with no adverse effect on important clinical outcomes.

Welander distal myopathy outside the Swedish population: phenotype and genotype.

Welander distal myopathy is a late onset disorder that is mainly seen in Sweden. It is linked to chromosome 2p13 and all Swedish patients show a common shared haplotype, indicating a founder mutation. Here we report the clinical manifestations, magnetic resonance imaging, pathophysiology and haplotype analysis of Welander patients in the Finnish population. The clinical examination of patients from 12 different families showed a distal myopathy with onset in the long extensor muscles of the hands and fingers, also seen in Swedish Welander patients. Muscle biopsies showed characteristic myopathic changes. Haplotype analysis with the five polymorphic markers that make up the common core haplotype, seen in the Swedish patients, revealed that this haplotype is also co-segregating in the Finnish patients and a common ancestry is therefore further supported for patients with Welander distal myopathy.

Kinetic analysis and test-retest variability of the radioligand [11C](R)-PK11195 binding to TSPO in the human brain - a PET study in control subjects.

BACKGROUND: Positron-emission tomography and the radioligand [11C](R)-PK11195 have been used for the imaging of the translocator protein (TSPO) and applied to map microglia cells in the brain in neuropsychiatric disorders. [11C](R)-PK11195 binding has been quantified using reference region approaches, with the reference defined anatomically or using unsupervised or supervised clustering algorithms. Kinetic compartment modelling so far has not been presented. In the present test-retest study, we examine the characteristics of [11C](R)-PK11195 binding in detail, using the classical compartment analysis with a metabolite-corrected arterial input function. METHODS: [11C](R)-PK11195 binding was examined in six control subjects at two separate occasions, 6 weeks apart. Results of one-tissue and two-tissue compartment models (1TCM, 2TCM) were compared using the Akaike criteria and F-statistics. The reproducibility of binding potential (BPND) estimates was evaluated by difference in measurements (error in percent) and intraclass correlation coefficients (ICCs). RESULTS: [11C](R)-PK11195 binding could be described by 2TCM which was the preferred model. Measurement error (in percent) indicated good reproducibility in large brain regions (mean error: whole brain 4%, grey matter 5%), but not in smaller subcortical regions (putamen 25%, caudate 55%). The ICC values were moderate to low, highest for the white matter (0.73), whole brain and thalamus (0.57), and cortical grey matter (0.47). Sizeable [11C](R)-PK11195 BPND could be identified throughout the human brain (range 1.11 to 2.21). CONCLUSIONS: High intra-subject variability of [11C](R)-PK11195 binding limits longitudinal monitoring of TSPO changes. The interpretation of [11C](R)-PK11195 binding by 2TCM suggests that the presence of specific binding to TSPO cannot be excluded at physiological conditions.

Refined mapping of the Welander distal myopathy region on chromosome 2p13 positions the new candidate region telomeric of the DYSF locus.

Welander distal myopathy (WDM) is a late adult-onset autosomal dominant disorder, characterized by a slow progression and distal limb weakness of the extremity muscles. The WDM locus has been mapped to chromosome 2p13. Within this region a common shared haplotype co-segregates in all affected patients, indicating a founder effect. By undertaking an extended linkage analysis we have significantly reduced the WDM locus to a critical interval of approximately 1.2 Mb flanked by markers D2S358 and PAC3-H52. The dysferlin gene, a strong candidate gene responsible for two other distal myopathies in the same region, is located centromeric to PAC3-H52 and can thereby formally be excluded as cause for WDM.