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.