Control definition
We used two control groups:
Non-genetic controls: LB, FD from 20 weeks gestation, and TOPFA with all other major CA subgroups, excluding CA subgroup types that were defined as cases or related to case CA subgroups, and excluding genetic syndromes (Figure 2).
Genetic controls: LB, FD from 20 weeks’ gestation, and TOPFA, with a diagnosis of a genetic syndrome (Figure 2).