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J Med Genet 49:630-635 doi:10.1136/jmedgenet-2012-101142
  • New loci

Study of autosomal recessive osteogenesis imperfecta in Arabia reveals a novel locus defined by TMEM38B mutation

  1. Fowzan S Alkuraya1,2,6
  1. 1Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
  2. 2Department of Pediatrics, King Khalid University Hospital and College of Medicine, King Saud University, Riyadh, Saudi Arabia
  3. 3Department of Pediatrics, King Fahad Medical City, Riyadh, Saudi Arabia
  4. 4Department of Child Health, Royal Hospital, Muscat, Oman
  5. 5Department of Medical Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
  6. 6Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
  7. 7Department of Orthopedic Surgery, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
  1. Correspondence to Dr Fowzan S Alkuraya, Developmental Genetics Unit, King Faisal Specialist Hospital and Research Center, MBC-03 PO BOX 3354, Riyadh 11211, Saudi Arabia; falkuraya{at}kfshrc.edu.sa
  • Received 1 August 2012
  • Revised 31 August 2012
  • Accepted 4 September 2012

Abstract

Background Osteogenesis imperfecta (OI) is an hereditary bone disease in which increased bone fragility leads to frequent fractures and other complications, usually in an autosomal dominant fashion. An expanding list of genes that encode proteins related to collagen metabolism are now recognised as important causes of autosomal recessive (AR) OI. Our aim was to study the contribution of known genes to AR OI in order to identify novel loci in mutation-negative cases.

Methods We enrolled multiplex consanguineous families and simplex cases (also consanguineous) in which mutations in COL1A1 and COL1A2 had been excluded. We used autozygome guided mutation analysis of AR OI (AR OI) genes followed by exome sequencing when such analysis failed to identify the causative mutation.

Results Two simplex and 11 multiplex families were enrolled, encompassing 27 cases. In three multiplex families, autozygosity and linkage analysis revealed a novel recessive OI locus on chromosome 9q31.1-31.3, and a novel truncating deletion of exon 4 of TMEM38B was identified within that interval. In addition, gonadal or gonadal/somatic mosaic mutations in COL1A1 or COL1A2 and homozygous mutations in recently described AR OI genes were identified in all remaining families.

Conclusions TMEM38B is a novel candidate gene for AR OI. Future studies are needed to explore fully the contribution of this gene to AR OI in other populations.