RNF213 and familial isolated congenital asplenia: The frequency of RNF213 p.Arg4810Lys was 6.2% (10/159) in the ICAS-only group, 8.3% (2/24) in the ECAS-only group, and 22% (10/46) in the concurrent ICAS and ECAS group, compared with 0.8% (1/131) in the control group.