CLRN1 and Usher syndrome type 3A: Pathogenic variants in CLRN1 (clarin 1) cause either non-syndromic retinitis pigmentosa (RP) (Khan et al. 2011) or Usher syndrome type 3A (USH3A), that is characterized by progressive hearing loss, RP and variable vestibular dysfunction (Adato et al. 2002; Joensuu et al. 2001; Ness et al. 2003; Plantinga et al. 2005).