BUB1B and embryonal rhabdomyosarcoma: While most variants were heterozygous and therefore of unknown relevance (Table 1), one patient with embryonal rhabdomyosarcoma (PaedCan07) carried two compound-heterozygous likely pathogenic variants in BUB1B. A heterozygous frameshift variant (c.2405_2406del, p.(Ser802Cysfs*29)) was inherited from his healthy father, a likely pathogenic second variant in BUB1B (c.2577+5 G > A, p.()?