Hereditary haemorrhagic telangiectasia, or Osler-Rendu-Weber (ORW) syndrome, is an autosomal dominant vascular dysplasia. So far, two loci have been demonstrated for ORW. Linkage studies established an ORW locus at chromosome 9q3; endoglin was subsequently identified as the ORW1 gene. A second locus, designated ORW2, was mapped to chromosome 12. Here we report a new 4 cM interval for ORW2 that does not overlap with any previously defined. A 1.38-Mb YAC contig spans the entire interval. It includes the activin receptor like kinase 1 gene (ACVRLK1 or ALK1), a member of the serine-threonine kinase receptor family expressed in endothelium. We report three mutations in the coding sequence of the ALK1 gene in those families which show linkage of the ORW phenotype to chromosome 12. Our data suggest a critical role for ALK1 in the control of blood vessel development or repair.

Gefitinib is well tolerated and has activity in patients with recurrent glioblastoma. Further study of this agent at higher doses is warranted.

BACKGROUND Fragile X Syndrome (FXS) is a trinucleotide repeat disease that is caused by the expansion of CGG sequences in the 5’ untranslated region of the FMR1 gene. Molecular diagnoses of FXS and other emerging FMR1 disorders typically rely on two tests, PCR and Southern blotting. However, performance or throughput limitations in these methods currently constrain routine testing. METHODS We evaluated a novel FMR1 gene-specific PCR technology with 20 cell line DNA templates and 146 blinded clinical specimens. The CGG repeat number was determined by fragment sizing of PCR amplicons using capillary electrophoresis and compared with the results of FMR1 Southern blotting performed with the same samples. RESULTS The FMR1 PCR accurately detected full mutation alleles up to at least 1300 CGG repeats and comprising >99% GC character. All categories of alleles detected by Southern blot, including 66 specimens with full mutations, were also identified by FMR1 PCR for each of 146 clinical specimens. Since all full mutation alleles in heterozygous female samples were detected by PCR, allele zygosity was reconciled in every case. The PCR reagents also detected a 1% mass fraction of a 940 CGG allele in a background of 99% 23 CGG allele—roughly 5-fold greater sensitivity than Southern blotting. CONCLUSIONS The novel PCR technology can accurately categorize the spectrum of FMR1 alleles, including alleles previously considered too large to amplify, reproducibly detect low abundance full mutation alleles, and correctly infer homozygosity in female specimens, thus greatly reducing the need for sample reflexing to Southern blot.

(CGG) n repeat expansion in the FMR1 gene is associated with fragile X syndrome and other disorders. Current methods for FMR1 molecular testing rely on Southern blot analysis to detect expanded alleles too large to be PCR-amplified and to identify female homozygous alleles that often confound interpretations of PCR data. A novel , single-tube CGG repeat primed FMR1 PCR technology was designed with two genespecific primers that flank the triplet repeat region, as well as a third primer that is complementary to the (CGG) n repeat. This PCR was evaluated with 171 unique DNA samples , including a blinded set of 146 clinical specimens. The method detected all alleles reported by Southern blot analysis , including full mutations in 66 clinical samples and comprised up to 1300 CGG. Furthermore , a blinded cohort of 42 female homozygous and heterozygous specimens, including 21 with full mutation alleles , was resolved with 100% accuracy. Last , AGG interrupter sequences, which may influence the risk of (CGG) n expansion in the children of some carriers , were each correctly identified in 14 male and female clinical samples as referenced to DNA sequencing. As a result , this PCR provides robust detection of expanded alleles and resolves allele zygosity , thus minimizing the number of samples that require Southern blot analysis and producing more comprehensive FMR1 genotyping data than other methods. Expansion of cytosine-guanine-guanine (CGG) triplet repeats in the 5Ј-untranslated region of the fragile X mental retardation 1 (FMR1, NM_002024.4) gene is associated with several disorders, including fragile X syndrome, fragile X-associated tremor/ataxia syndrome, and fragile X-associated primary ovarian insufficiency. [1][2][3][4] Patients with the FMR1 full mutation (Ͼ200 CGG repeats) may be affected by a range of neurological, psychiatric, or emotional challenges, including mental retardation and/or autism.5 Deficits in development and particularly in attention and social communication have also been noted for many children with the FMR1 premutation. Moreover, premutation carriers (55 to 200 CGG repeats) are known to be at risk for fragile X-associated primary ovarian insufficiency and fragile X-associated tremor/ataxia syndrome, and some of these individuals may present additional complications, such as hypothyroidism and fibromyalgia.6 As a result, FMR1 disorders are linked to a range of clinical conditions, necessitating testing patients at different times during their life span. 7Fragile X syndrome molecular diagnosis is usually based on quantification of the (CGG) n repeat elements and the assessment of the methylation state of expanded alleles.5 Although PCR is the preferred approach to determine the (CGG) n repeat length of FMR1 alleles, typically only alleles with less than 100 to 150 CGG have