UMLS MRREL.RRF contains Parent/Child & Broader/Narrow relationships 2023AB: # type 629,121 AQ 5,231,192 CHD 5,231,192 PAR 629,121 QB 1,790,195 RB 53,182 RL 1,790,195 RN 17,829,794 RO 3,742,256 RQ 7,121,016 SY