1. ¹Department of Medical Genetics, University of Antwerp, Universiteitsplein 1, Antwerp, Belgium
2. ²Clinical Psychoacoustics and Neurootology Laboratory, Neuroscience Department, Aristotle University of Thessaloniki, AHEPA Hospital, Thessaloniki, Greece
3. ³Molecular Otolaryngology Research Laboratories, Department of Otolaryngology, University of Iowa, 200 Hawkins Drive, Iowa City, IA, USA
4. ⁴Otolaryngology Departement, St Lucas Clinic, Thessaloniki, Greece
5. ⁵Department of Genetics, Institute of Child Health, 'Aghia Sophia' Children's Hospital, Athens, Greece
6. ⁶Department of Otorhinolaryngology, University Medical Center St Radboud, Philips van Leydenlaan 15, Nijmegen, The Netherlands

Correspondence: Professor G Van Camp, Department of Medical Genetics, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium. Tel: +323 820 2491; Fax: +323 820 2566; E-mail: Guy.VanCamp@ua.ac.be

Received 24 March 2006; Revised 2 November 2006; Accepted 16 November 2006; Published online 10 January 2007.

Abstract

Otosclerosis is a common form of hearing impairment among white adults with a prevalence of 0.3–0.4%. It is caused by abnormal bone homeostasis of the otic capsule that compromises free motion of the stapes in the oval window. Otosclerosis is in most patients a multifactorial disease, caused by both genetic and environmental factors. In some cases, the disease is inherited as a monogenic autosomal dominant trait, sometimes with reduced penetrance. However, families large enough for genetic linkage studies are extremely rare. To date, five loci (OTSC1-5) have been reported, but none of the responsible genes have been cloned yet. An additional locus, OTSC6, has been reported to the HUGO nomenclature committee but the relevant linkage study has not been published. In this study, a genome-wide linkage study was performed in a large Greek pedigree segregating autosomal dominant otosclerosis. A seventh locus, OTSC7, was localized on chromosome 6q13–16.1 with a multipoint LOD score of 7.5 in the 13.47 cM region defined by markers D6S1036 (centromeric) and D6S300 (telomeric). Linkage analysis of this new locus in 13 smaller Belgian and Dutch families has identified one family from The Netherlands in which allele segregation suggests linkage to this region. The overlap between the critical regions of these two families is a 1.06 Mb interval between the genetic markers D6S1036 (centromeric) and D6S406 (telomeric) on chromosome 6q13.