(A) SSU processome factors with disease-causing mutations are highlighted within state post-A1. MC, microcephaly; BWCNS, Bowen-Conradi syndrome; NAIC, North American Indian childhood cirrhosis; 5q-, 5q- syndrome; DBA, Diamond-Blackfan anemia; ACC, aplasia cutis congenita. (B) Detailed view of AROS (yellow, transparent surface) and its interacting proteins. DBA1-causing mutations in eS19 are colored red. (C) Detailed view of BMS1 (orange), uS12 (gray), and neighboring proteins. Disease-causing mutations in BMS1 (ACC) and uS12 (MC) are labeled and shown as red spheres. (D) A close-up view of the interface between eS19 (gray) and AROS (yellow, transparent surface). DBA1-causing mutations in eS19 are labeled and shown as red sticks.