20 novel point mutations and one large deletion in EXT1 and EXT2 genes: Report of diagnostic screening in a large Italian cohort of patients affected by hereditary multiple exostosis

Michele Ciavarella, Michelina Coco, Filomena Baorda, Pietro Stanziale, Massimiliano Chetta, Luigi Bisceglia, Pietro Palumbo, Mario Bengala, Paola Raiteri, Margherita Silengo, Camilla Caldarini, Renato Facchini, Roberto Lala, Maria Luigia Cavaliere, Davide De Brasi, Barbara Pasini, Leopoldo Zelante, Vito Guarnieri, Leonardo D'Agruma

Research output: Contribution to journalArticlepeer-review

Abstract

Background: Hereditary multiple exostosis represents the most frequent bone tumor disease in humans. It consists of cartilage deformities affecting the juxta-ephyseal region of long bones. Usually benign, exostosis could degenerate in malignant chondrosarcoma form in less than 5% of the cases. Being caused by mutations in the predicted tumor suppressor genes, EXT1 (chr 8q23-q24) and EXT2 (chr 11p11-p12) genes, HMEs are usually inherited with an autosomal dominant pattern, although ". de novo" cases are not infrequent. Aim: Here we present our genetic diagnostic report on the largest Southern Italy cohort of HME patients consisting of 90 subjects recruited over the last 5. years. Results: Molecular screening performed by direct sequencing of both EXT1 and EXT2 genes, by MLPA and Array CGH analyses led to the identification of 66 mutations (56 different occurrences) and one large EXT2 deletion out of 90 patients (74.4%). The total of 21 mutations (20 different occurrences, 33.3%) and the EXT2 gene deletion were novel. In agreement with literature data, EXT1 gene mutations were scattered along all the protein sequence, while EXT2 lesions fell in the first part of the protein. Conservation, damaging prediction and 3-D modeling, in-silico, analyses, performed on three novel missense variants, confirmed that at least in two cases the novel aminoacidic changes could alter the structure stability causing a strong protein misfolding. Conclusions: Here we present 20 novel EXT1/. EXT2 mutations and one large EXT2 deletion identified in the largest Southern Italy cohort of patients affected by hereditary multiple exostosis.

Original languageEnglish
Pages (from-to)339-348
Number of pages10
JournalGene
Volume515
Issue number2
DOIs
Publication statusPublished - Feb 25 2013

Keywords

  • Exostosis
  • EXT1
  • EXT2
  • Mutation

ASJC Scopus subject areas

  • Genetics

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