No evidence of linkage between 7q33-36 locus (OTSC2) and otosclerosis in seven British Caucasian pedigrees

Background: The aetiology of otosclerosis is complex, and probably involves an interaction between genes and environmental factors. Previous studies have revealed genetic linkage with a number of chromosome regions, including position 7q33-36. Aim: To confirm whether linkage exists between otosclerosis and chromosome region 7q33-36. Materials and methods: Seven multiply affected families were ascertained. Deoxyribonucleic acid from members of these families was extracted, and six markers were genotyped to cover a 16 cM region at 7q33-36. Both parametric and non-parametric multipoint linkage analyses were performed. Results: Parametric multipoint linkage analysis excluded any linkage at 7q33-36 (logarithm of odds score < -4.0). Non-parametric linkage analysis also failed to confirm any linkage (non-parametric linkage < 1.66). When tested individually, pedigree four was the only one to show a significant non-parametric linkage score between D7s684 and D7s2513 (non-parametric linkage = 1.96). Conclusion: No linkage was detected between otosclerosis and the 7q33-36 region. This could be explained by the study's lack of power, due to the limited number of families available.