In order to identify additional cases with PTCHD1 mutations, we sequenced the coding regions in 900 (M=723; F=177) unrelated ASD cases and 225 unrelated male ID cases. Seven missense changes were identified in six unrelated ASD probands and two ID probands (Fig. 2; fig. S1 & fig. S2; table S1). All of these variants, which resulted in the substitution of highly conserved amino acids, were inherited from unaffected carrier mothers (fig. S1). In six of the eight families the missense variants appear to segregate with the phenotype, however in Family 6 L73F did not segregate, and in Family 7 the A470D did not segregate in different loops (not shown) of the extended pedigree (see Fig. 2 and table S1 for details).
