MKS1 and retinitis pigmentosa: In patients with a variety of syndromic ciliopathies attributed to variants in NPHP3, IQCB1, CEP290, and MKS1, a common RPGRIP1L variant (p.Arg229Thr) (present in over 8% of South Asians and 3% of other populations) is significantly enriched in patients who also have retinitis pigmentosa [44,122].