Mutation analysis in Norwegian families with hereditary hemorrhagic telangiectasia: founder mutations in ACVRL1.

Hereditary hemorrhagic telangiectasia (HHT, Osler-Weber-Rendu disease) is an autosomal dominant inherited disease defined by the presence of epistaxis and mucocutaneous telangiectasias and arteriovenous malformations (AVMs) in internal organs. In most families (~85%), HHT is caused by mutations in the ENG (HHT1) or the ACVRL1 (HHT2) genes. Here, we report the results of genetic testing of 113 Norwegian families with suspected or definite HHT. Variants in ENG and ACVRL1 were found in 105 families (42 ENG, 63 ACVRL1), including six novel variants of uncertain pathogenic significance. Mutation types were similar to previous reports with more missense variants in ACVRL1 and more nonsense, frameshift and splice-site mutations in ENG. Thirty-two variants were novel in this study. The preponderance of ACVRL1 mutations was due to founder mutations, specifically, c.830C>A (p.Thr277Lys), which was found in 24 families from the same geographical area of Norway. We discuss the importance of founder mutations and present a thorough evaluation of missense and splice-site variants.

Rapid, universal method to isolate PCR-ready DNA using magnetic beads.

A magnetic bead-based system for DNA isolation utilizing monodisperse beads was tested with the aim of producing a general approach for PCR-ready DNA. This commercially available system was originally designed for isolating PCR-ready DNA from human whole blood. We tested diverse organisms belonging to the major groups: bacteria, fungi, algae, vascular plants and vertebrates. Optimization of sample amounts and lysis conditions was done using several types of tissue (fish epithelium, plant leaves, mammalian liver and muscle tissues, fungal fruit-bodies and mycelium). The standard lysis conditions used for blood could be applied with good results for most bacteria, algae and vertebrates, while plant leaves and fungal fruit-bodies had to be mechanically broken to obtain proper lysis. For vascular plants and some cyanobacteria, lysis by heating to 65 degrees C gave better DNA yields than standard lysis at room temperature. In all cases, DNA suitable for PCR was prepared in less than 30 min. The PCR products yielded 350 to 500 bases of DNA sequence (99% accurate) by direct manual or automated sequencing.