The cochlea normally has 2 &amp; half turns, but in pendred syndrome, there can be 1 &amp; half turn only, due to abnormal dilatation of endolymphatic sack.
NIH Medical Arts
<a rel="nofollow" class="external text" href="http://www.nidcd.nih.gov/health/hearing/pages/pendred.aspx">Pendred Syndrome</a> at the NIH