Genetic refinement of the hereditary neuralgic amyotrophy (HNA) locus at chromosome 17q25.

Hereditary neuralgic amyotrophy (HNA) is an autosomal dominant, recurrent focal neuropathy. HNA is characterised by episodes of painful brachial plexus neuropathy with muscle weakness and atrophy, as well as sensory disturbances. Single episodes are commonly preceded by non-specific infections, immunisations or parturition. Mild dysmorphic features and short stature are present in some HNA families, but absolute co-segregation with HNA has not been described. To refine the previously described HNA locus on chromosome 17q25, we performed a genetic linkage study in five HNA families with different geographic origins. Significant linkage was obtained with chromosome 17q24-q25 short tandem repeat (STR) markers in three HNA families and suggestive linkage was found in the other two HNA families. Analysis of the informative recombinations in affected individuals allowed us to reduce the HNA linkage interval to a candidate region of 3.5 cM.

Giant axonal neuropathy (GAN): case report and two novel mutations in the gigaxonin gene.

Giant axonal neuropathy (GAN) is an autosomal recessive neurologic disorder clinically characterized by a severe polyneuropathy, CNS abnormalities, and characteristic tightly curled hair. Recently, mutations in the gigaxonin gene have been identified as the underlying genetic defect. The authors report two novel mutations confirming that GAN is caused by mutations in the gigaxonin gene and raise the question whether some mutations may cause a mild subclinical neuropathy.

A novel frameshift mutation in PMP22 accounts for hereditary neuropathy with liability to pressure palsies.

Peripheral myelin protein PMP22 deficiency is associated with hereditary neuropathy with liability to pressure palsies (HNPP). Most HNPP cases are caused by a 1.5-megabase deletion in chromosome 17p11.2-12, a region that contains the PMP22 gene, whereas point mutations leading to HNPP are extremely rare. We have identified a family with clinical and electrophysiologic features of HNPP,in which all affected members are heterozygous carriers of a single base insertion in codon 94. This mutation is predicted to alter the reading frame and to result in a delayed termination signal. We conclude that the functional consequences of the frameshift are equivalent to those of the PMP22 deletion allele.

Association between single nucleotide polymorphisms in the lysyl oxidase-like 1 gene and spontaneous cervical artery dissection.

BACKGROUND: Spontaneous cervical artery dissection (sCAD) is a common cause of stroke in patients below 55 years. Dermal connective tissue abnormalities have been observed in up to 60% of patients. A chromosomal locus for connective tissue abnormalities associated with sCAD has been mapped to chromosome 15q24 to a candidate region containing the lysyl oxidase-like 1 gene (LOXL1). LOXL1 an excellent candidate susceptibility gene for non-familial sCAD was investigated by mutation analysis and a genetic association study. METHODS: We sequenced the whole coding region of the LOXL1 gene in 15 sCAD patients and performed a genetic association study in 157 sCAD patients using 12 single nucleotide polymorphisms (SNP). RESULTS: The SNP rs3825942 (Gly153Asp) showed marginal association with sCAD on an allele basis and in the dominant genetic model, and intronic SNP rs893817 under a recessive model only. None of the SNP haplotypes was associated with sCAD. CONCLUSIONS: Genetic variation in LOXL1 might play a role as a risk factor for sCAD.

Significant variation in mortality and functional outcome after acute ischaemic stroke between Western countries: data from the tinzaparin in acute ischaemic stroke trial (TAIST).

BACKGROUND: The medical care of patients with acute stroke varies considerably between countries. This could lead to measurable differences in mortality and functional outcome. OBJECTIVE: To compare case mix, clinical management, and functional outcome in stroke between 11 countries. METHODS: All 1484 patients from 11 countries who were enrolled into the tinzaparin in acute ischaemic stroke trial (TAIST) were included in this substudy. Information collected prospectively on demographics, risk factors, clinical features, measures of service quality (for example, admission to a stroke unit), and outcome were assessed. Outcomes were adjusted for treatment assignment, case mix, and service relative to the British Isles. RESULTS: Differences in case mix (mostly minor) and clinical service (many of prognostic relevance) were present between the countries. Significant differences in outcome were present between the countries. When assessed by geographical region, death or dependency were lower in North America (odds ratio (OR) adjusted for treatment group only = 0.52 (95% confidence interval, 0.39 to 0.71) and north west Europe (OR = 0.54 (0.37 to 0.78)) relative to the British Isles; similar reductions were found when adjustments were made for 11 case mix variables and five service quality measures. Similarly, case fatality rates were lower in North America (OR = 0.44 (0.30 to 0.66)) and Scandinavia (OR = 0.50 (0.33 to 0.74)) relative to the British Isles, whether crude or adjusted for case mix and service quality. CONCLUSIONS: Both functional outcome and case fatality vary considerably between countries, even when adjusted for prognostic case mix variables and measures of good stroke care. Differing health care systems and the management of patients with acute stroke may contribute to these findings.

Infarctions and non-invasive diagnosis in moyamoya disease: two case reports.

An 31-year-old female and a 32-year-old male had clinical signs and angiographical confirmation of adult Moyamoya disease (MMD). Bilateral carotid siphon (C1), middle cerebral artery (M1), and anterior cerebral artery (A1) stenoses were diagnosed by means of transcranial Doppler sonography (TCD) and visualized during angio Magnetic Resonance Imaging (angio-MRI). In the woman, a 'rete mirabile' of dilated and tortuous lenticulostriate arteries could be visualized during proton weighted and T1-weighted MRI sequences. CO2-dependent vasomotor reactivity was bilaterally reduced and completely exhausted in the territory of right middle cerebral artery in both patients. Cerebral perfusion reserve, defined as the ratio of cerebral blood flow (CBF) to cerebral blood volume (CBV) was assessed by SPECT, and was found to be dramatically reduced in the anterior region of the male patient. Both patients had bilateral small subcortical infarctions in the corona radiata. TCD and MRI are important noninvasive techniques for a preliminary diagnosis of Moyamoya disease. Infarctions in Moyamoya disease may be hemodynamically produced low-flow infarctions.

A sequence-ready BAC/PAC contig and partial transcript map of approximately 1.5 Mb in human chromosome 17q25 comprising multiple disease genes.

Hereditary neuralgic amyotrophy (HNA) is an autosomal dominant recurrent neuropathy mapped to a 4-cM interval on chromosome 17q25 between the short tandem repeat (STR) markers D17S1603 and D17S802. Chromosome 17q25 in general and the 4-cM HNA region in particular are also implicated in the pathogenesis of a number of tumors (tylosis with esophageal cancer, sporadic breast and ovarian tumors) and harbor a psoriasis susceptibility locus. Initial attempts to construct a yeast artificial chromosome contig failed. Therefore, we have now constructed a complete P1 artificial chromosome (PAC) and bacterial artificial chromosome (BAC) contig of the region flanked by the STR markers D17S1603 and D17S802. The contig contains 22 PAC and 64 BAC clones and covers a physical distance of approximately 1. 5 Mb. A total of 83 sequence-tagged site (STS) markers (10 known STSs and STRs, 56 STSs generated from clone end-fragments, 12 expressed sequence tags, and 5 known genes) were mapped on the contig, resulting in an extremely dense physical map with approximately 1 STS per 20 kb. This sequence-ready PAC and BAC contig will be pivotal for the positional cloning of the HNA gene as well as other disease genes mapping to this region.

Tinzaparin in acute ischaemic stroke (TAIST): a randomised aspirin-controlled trial.

BACKGROUND: Low-molecular-weight heparins and heparinoids are superior to unfractionated heparin in the prevention and treatment of venous thromboembolism, but their safety and efficacy in acute ischaemic stroke are inadequately defined. METHODS: This randomised, double-blind, aspirin-controlled trial tested the safety and efficacy of treatment with high-dose tinzaparin (175 anti-Xa IU/kg daily; 487 patients), medium-dose tinzaparin (100 anti-Xa IU/kg daily; 508 patients), or aspirin (300 mg daily; 491 patients) started within 48 h of acute ischaemic stroke and given for up to 10 days. Primary intracerebral haemorrhage was excluded by computed tomography. Outcome was assessed, with treatment allocation concealed, by the modified Rankin scale at 6 months (independence [scores 0-2] vs dependence or death [scores 3-6]). FINDINGS: Of 1486 randomised patients, two did not receive treatment and 46 were lost to follow-up. The proportions independent at 6 months were similar in the groups assigned high-dose tinzaparin (194/468 [41.5%]), medium-dose tinzaparin (206/486 [42.4%]), or aspirin (205/482 [42.5%]). There was no difference in effect in any predefined subgroup, including patients with presumed cardioembolic stroke. Other outcome measures were similar between the treatment groups (disability, case-fatality, and neurological deterioration rates). During the in-hospital treatment period no patient assigned high-dose tinzaparin developed a symptomatic deep-vein thrombosis compared with nine assigned aspirin. Conversely, seven patients assigned high-dose tinzaparin developed symptomatic intracerebral haemorrhage compared with one in the aspirin group. INTERPRETATION: Treatment with tinzaparin, at high or medium dose, within 48 h of acute ischaemic stroke did not improve functional outcome compared with aspirin. Although high-dose tinzaparin was superior in preventing deep-vein thrombosis, it was associated with a higher rate of symptomatic intracranial haemorrhage.