In early September 2002, a reader of the published paper (Frans Cremers from The Netherlands) alerted us to an error in the way we calculated the frequency of heterozygous, unaffected carriers of recessive alleles causing retinitis pigmentosa.  This error is on page 1224 and in Figure 2 on that same page.  Specifically, we erroneously used the allele frequency as the measure of carrier frequency, a very simple and foolish error for which we apologize.  We corrected this mistake in a revised version of the paper. Please click here for a PDF file of the corrected paper.