Advances in human genetics in recent years have largely been driven by next-generation sequencing (NGS); however, the discovery of disease-related gene mutations has been biased toward the exome because the large and very repetitive regions that characterize the noncoding genome remain difficult to reach by that technology. For autosomal-dominant spinocerebellar ataxias (SCAs), 28 genes have been identified, but only five SCAs originate from non-coding mutations. Over half of SCA-affected families, however, remain without a genetic diagnosis. We used genome-wide linkage analysis, NGS, and repeat analysis to identify an (ATTTC) n insertion in a polymorphic ATTTT repeat in DAB1 in chromosomal region 1p32.2 as the cause of autosomal-dominant SCA; this region has been previously linked to SCA37. The non-pathogenic and pathogenic alleles have the configurations [(ATTTT) 7-400 ] and [(ATTTT) 60-79 (ATTTC) 31-75 (ATTTT) ], respectively. (ATTTC) n insertions are present on a distinct haplotype and show an inverse correlation between size and age of onset. In the DAB1-oriented strand, (ATTTC) n is located in 5 0 UTR introns of cerebellar-specific transcripts arising mostly during human fetal brain development from the usage of alternative promoters, but it is maintained in the adult cerebellum. Overexpression of the transfected (ATTTC) 58 insertion, but not (ATTTT) n , leads to abnormal nuclear RNA accumulation. Zebrafish embryos injected with RNA of the (AUUUC) 58 insertion, but not (AUUUU) n , showed lethal developmental malformations. Together, these results establish an unstable repeat insertion in DAB1 as a cause of cerebellar degeneration; on the basis of the genetic and phenotypic evidence, we propose this mutation as the molecular basis for SCA37.

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Headache is the most frequent presenting symptom of cerebral venous thrombosis (CVT), most commonly associated with other manifestations. It has been described as its only clinical presentation in 15 % of patients. There is no typical pattern of headache in CVT. The objective of this study was to study the characteristics of headache as the sole manifestation of CVT. From a prospective study of 30 consecutive patients diagnosed with CVT over 18 months, we selected those who presented with headache only: they had a normal neurological examination, no papilloedema and no blood or any parenchymal lesion on CT scan. All were submitted to a systematic etiological workup and a structured questionnaire about the characteristics of headache was provided. Headache was the sole manifestation of CVT in 12 patients; it was diffuse or bilateral in the majority. Seven patients referred worsening with sleep/lying down, Valsalva maneuvers or straining. There was no association between the characteristics of headache and extension of CVT. Time from onset to diagnosis was significantly delayed in these patients presenting only with headache. In our series, 40 % of patients presented only with headache. There was no uniform pattern of headache apart from being bilateral. There was a significant delay of diagnosis in these patients. Some characteristics of headache should raise the suspicion of CVT: recent persistent headache, thunderclap headache or pain worsening with straining, sleep/lying down or Valsalva maneuvers even in the absence of papilloedema or focal signs.

Alzheimer's disease (AD) is a neurodegenerative disorder of still unknown etiology and the leading cause of dementia worldwide. Besides its main neuropathological hallmarks, a dysfunctional homeostasis of transition metals has been reported to play a pivotal role in the pathogenesis of this disease. Dysregulation of iron (Fe) metabolism in AD has been suggested, particularly at the level of cellular iron efflux. Herein, we intended to further clarify the molecular mechanisms underlying Fe homeostasis in AD. In order to achieve this goal, the expression of specific Fe metabolism-related genes directly involved in Fe regulation and export was assessed in peripheral blood mononuclear cells (PBMCs) from 73AD patients and 74 controls by quantitative PCR. The results obtained showed a significant decrease in the expression of aconitase 1 (ACO1; P=0.007); ceruloplasmin (CP; P<0.001) and amyloid-beta precursor protein (APP; P=0.006) genes in AD patients compared with healthy volunteers. These observations point out to a significant downregulation in the expression of genes associated with ferroportin-mediated cellular Fe export in PBMCs from AD patients, when compared to controls. Taken together, these findings support previous studies suggesting impairment of Fe homeostasis in AD, which may lead to cellular Fe retention and oxidative stress, a typical feature of this disease.

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