A ubiquitous chromatin opening element (UCOE) confers resistance to DNA methylation-mediated silencing of lentiviral vectors.

DNA methylation may restrict the activity of gene transfer vectors due to inadvertent silencing. In P19 embryonic carcinoma cells in vitro, we found that transgene expression regulated by the SFFV LTR and EF1 alpha promoter declined rapidly within 16 days, but for A2UCOE derived from the human HNRPA2B1-CBX3 housekeeping gene locus, remained completely stable. Silencing correlated with extensive epigenetic methylation of CpG sites, whereas the A2UCOE was almost completely resistant. Linking of the A2UCOE upstream of the SFFV LTR protected this element from both DNA methylation and silencing. Analysis of engrafted hematopoietic cells in vivo transduced with the same vectors revealed a similar pattern. The A2UCOE displayed little or no methylation in either primary or secondary graft recipients, and gene expression profiles were highly conserved between the two groups. These studies provide convincing evidence that DNA methylation plays a direct role in regulating self-inactivating (SIN) lentiviral transgene expression, and that the stability of expression from the A2UCOE is, at least in part, due to methylation resistance. The A2UCOE therefore has considerable utility for gene therapy applications where reliable and sustained gene expression is desirable.

Heterozygous deletion of a 2-Mb region including the dystroglycan gene in a patient with mild myopathy, facial hypotonia, oral-motor dyspraxia and white matter abnormalities.

Dystroglycan is a protein which binds directly to two proteins defective in muscular dystrophies (dystrophin and laminin alpha2) and whose own aberrant post-translational modification is the common aetiological route of neuromuscular diseases associated with mutations in genes encoding at least six other proteins (POMT1, POMT2, POMGnT1, LARGE, FKTN and FKRP). It is surprising, therefore, that to our knowledge no mutations of the human dystroglycan gene itself have yet been reported. In this study, we describe a patient with a heterozygous de novo deletion of a approximately 2-Mb region of chromosome 3, which includes the dystroglycan gene (DAG1). The patient is a 16-year-old female with learning difficulties, white matter abnormalities, elevated serum creatine kinase, oral-motor dyspraxia and facial hypotonia but minimal clinically significant involvement of other muscles. As these symptoms are a subset of those observed in disorders of dystroglycan glycosylation (muscle-eye-brain disease and Warker-Warburg syndrome), we assess the likely contribution to her phenotype of her heterogosity for a null mutation of DAG1. We also show that the transcriptional compensation observed in the Dag1(+/-) mouse is not observed in the patient. Although we cannot show that haploinsufficiency of DAG1 is the sole cause of this patient's myopathy and white matter changes, this case serves to constrain our ideas of the severity of the phenotypic consequences of heterozygosity for null DAG1 mutations.

Serological screening for coeliac disease in adults with Turner's syndrome: prevalence and clinical significance of endomysium antibody positivity.

OBJECTIVE: To investigate the prevalence of coeliac disease (CD) in an adult population with Turner's syndrome (TS). Design A clinic population with TS was screened using a serological test for CD. METHODS: Two hundred and fifty six patients with TS were included in the study. Five patients had existing diagnoses of CD. The remaining 251 asymptomatic patients were screened using an IgA endomysium antibody (EMA) test. Positive cases were offered endoscopy with duodenal biopsy. HLA typing was undertaken in existing cases and new EMA-positive cases. RESULTS: Of the 251 patients screened, eight were found to be EMA positive (3.2%). Seven patients proceeded to duodenal biopsy on which all were confirmed histologically to have cluster of differentiation (2.8%). The prevalence of subclinical cluster of differentiation in the population can therefore be estimated between 2.8 and 3.2%. The total population prevalence of CD, including the previously diagnosed cases, is estimated between 4.7 and 5.1%. Ten patients with histologically confirmed cluster of differentiation underwent HLA typing of which eight were HLA-DQ2 positive, one was HLA-DQ8 positive and one was negative to both HLA-DQ2 and HLA-DQ8. CONCLUSIONS: This study demonstrates an increased prevalence of cluster of differentiation in an adult population with TS over the general population. This is consistent with previous data published in paediatric populations.