This suggests that haploinsufficiency of Ptch1 is sufficient for rhabdomyosarcoma formation in a murine model.39,40 Our western blot results indicated that the heterozygous c.403C>T (p.R135X) truncating mutation in PTCH1, resulting in PTCH1 haploinsufficiency, might also be sufficient to promote OKC development, possibly due to loss of negative feedback from PTCH1. Here, PTCH1 is linked to rhabdomyosarcoma.