No abstract

Our findings cast doubt on the reliability of centromeric probes for aneuploidy screening. The analysis of chromosome position in sperm heads should be further investigated for the screening of infertile men.

No abstract

Introductionvon Willebrand factor (VWF) is a multimeric adhesive glycoprotein that plays several key roles in hemostasis. It mediates platelet adhesion and aggregation at the sites of vascular injury, and acts as a carrier for coagulation factor VIII to protect it from proteolytic degradation. 1,2 VWF plasma levels below 50% are found in the most common type of von Willebrand disease (VWD), type 1 VWD, which is characterized by a mild/moderate deficiency of functionally normal VWF. The understanding of the genetic basis and molecular pathophysiology of type 1 VWD has been a challenge, and a heterogeneous array of VWF gene mutations, located throughout the gene, have been documented in these patients. The details of these mutations are listed and updated on the ISTH VWF SSC Database (http://www.sheffield.ac.uk/ VWF/index.html).Three large population studies of type 1 VWD patients have detailed the spectrum of VWF gene mutations in several European Countries and in Canada. However, candidate pathogenic VWF mutations were not found in 27%, 3 in 36%, 4 and in 28% 5 of index cases diagnosed with type 1 VWD. In the Canadian study, 8 sequence variations within the 5Ј regulatory region of the VWF gene were found after sequencing DNA from 123 index cases with type 1 VWD. These 5Ј regulatory sequence changes represented 16% of the total candidate mutations found in this study. However, to date, there has been no functional evidence to support the pathogenic nature of any of these sequence variations.Earlier VWF promoter studies have indicated that, in vitro, the basal transcription of the human VWF gene is mediated through a region in the promoter located between base pairs Ϫ89 and ϩ19 (relative to transcription start site, TSS ϩ1). This region was functional in both endothelial and nonendothelial cell types. 6 In vivo studies demonstrated that VWF sequences between Ϫ487 to ϩ247 are responsible for promoter activation in brain vascular endothelial cells. 7 The Ϫ60/ϩ19 region has been shown to be a critical area within the VWF gene promoter, possessing 2 Ets-binding motifs, with the 5Ј-most motif being more critical to transcriptional activation. 6 In transgenic mice, a larger VWF fragment (2182 bp) containing the 5Ј-flanking sequences and including exon 1 and intron 1 of the gene has been shown to activate transgene expression in endothelial cells of the heart, skeletal muscles, and brain, 8 suggesting that additional distant VWF gene sequences are required for expression in other vascular endothelial cells in vivo. Specific interaction between positive and negative regulatory sequences together with their transcription factors have been identified within this region and have contributed to the endothelial-specific VWF mRNA expression levels. 6,9,[10][11] The local vascular microenvironment also appears to contribute to the regulation of endothelial VWF expression, 8 and it is well recognized that there is considerable heterogeneity in the distribution and nature of endothelial VWF expression throughout the vasculature. 1...

Summary Background von Willebrand factor (VWF) variant c.2771G>A; p.R924Q has been described as a benign polymorphism or a possible marker for a null allele and been associated with mild bleeding phenotypes. It was identified in several patients in recent type 1 von Willebrand disease (VWD) studies. Objectives To determine whether the p.R924Q allele contributes to reduced VWF levels and type 1 VWD. Methods 1115 healthy controls and 148 index cases from the MCMDM-1VWD study were genotyped for c.2771G>A; VWF and FVIII levels were analysed in ABO blood group stratified individuals and the p.R924Q variant was expressed in 293 EBNA cells. Results c.2771G>A was present in six index cases, five of whom had a second VWF variant which likely contributed to phenotype. A common core haplotype identified in families, which included the rare G allele of c.5843-8C>G was present in the majority of 35 c.2771G>A heterozygous controls. c.2771G>A contributed about 10% variance in VWF and FVIII levels in controls and 35% variance when co-inherited with blood group O. Recombinant p.R924Q VWF had no effect on in vitro expression and heterozygous family members had normal VWFFVIII binding and normal clearance of VWF and FVIII. Conclusions The allele bearing c.2771A leads to reductions in VWF and FVIII levels particularly in combination with blood group O. Its inheritance alone may be insufficient for VWD diagnosis, but it appears to be associated with further VWF level reduction in individuals with a second VWF mutation and it contributes to population variance in VWF and FVIII levels.

The LungCarta panel is a sensitive method of screening for multiple alterations (214 mutations across 26 genes) and which optimizes the use of limited amounts of tumor DNA isolated from small specimens.

that the former display a significant non-random pattern for all autosomal loci, but there is a less distinct, possibly random, pattern in 'NDA' nuclei. No evidence was found that the presence of an extra chromosome is accompanied by an altered nuclear location for that chromosome. Centromeric loci on chromosomes 15 and 16 normally seen at the nuclear periphery were mostly centrally located in aneuploid cells, providing some evidence of a 'chromocentre'; however, the chromosome-18 centromere was more peripheral, similar to committed cells. Our results provide clues to the nature of totipotency in human cells and might have future applications for preimplantation diagnosis and nuclear transfer.

The PI3K-AKT signalling cascade has a highly conserved role in a variety of processes including cell growth and glucose homoeostasis. Variants affecting this pathway can lead to one of several segmental overgrowth disorders. These conditions are genetically heterogeneous and require tailored, multidisciplinary involvement throughout life. Hypoglycaemia is common in other overgrowth syndromes but has been described only sporadically in association with PIK3CA and CCND2 variants. We report a cohort of 6 children with megalencephaly-capillary malformation (MCAP) and megalencephaly-polydactyly-polymicrogyria-hydrocephalus (MPPH) syndromes who developed clinically significant hypoglycaemia. Based on our findings, we suggest that segmental overgrowth patients should be screened for low blood glucose levels during childhood and there should be early specialist endocrine review in any children who develop hypoglycaemia.