Cluster 45: document willingness understand sign ability written informed consent subject subjects Cluster 584: understand ability informed consent provide willingness written nature signed study Cluster 694: participate study consent willing patients informed patient refuse willingness ability Cluster 704: ability consent informed willingness donor patients lack demonstrate precludes likely Cluster 705: voluntarily understand ability informed consent sign form document willingness fanca Cluster 776: sign willingness understand ability written informed consent subjects registration patients Cluster 1877: consent informed patients capacity willingness documented refuses assent subjects understand Cluster 2173: competent mentally consent informed sign understand form willingness ability irb Cluster 2351: sign willingness form understand ability consent informed written study initiation