CTNNB1 and hemoglobin measurement: Therefore, it suggests different natural histories leading to HB development: HB can arise either in an 11p15.5 predisposing context (cn-LOH or epimutation IC2) followed by a CTNNB1 point mutation or directly through CTNNB1 large deletion and synchronous or late 11p15.5 cn-LOH/IC1 epimutation.