Figure 1. Inheritance patterns in children with cancer.

(A–C) Autosomal dominant inheritance—transmitted by the affected (or as yet clinically unaffected) father (A), transmitted by parental (in this case paternal) mosaicism (B), and originated de novo (C). (D, E) Autosomal recessive inheritance—transmitted by both unaffected parents (D) and one variant transmitted by an unaffected parent (in this case the father) and one originated de novo (E). (F) Concomitant digenic inheritance of two heterozygous variants exemplified by two germline variants in PTCH1 and PTCH2 in a newborn with congenital rhabdomyosarcoma, leading to activation of the sonic hedgehog signaling pathway. The PTCH1 variant is inherited by the mother, while the PTCH2 variant is inherited by the father. Both parents are clinically unaffected so far.