KMT2C and Kleefstra syndrome: In the third group, the KMT2C (MLL3/HALR) and KMT2D (MLL4/ALR) COMPASS-like complexes (KCDCOMs, also historically known as ASC2-binding complexes, ASCOMs) bind the largest number of unique subunits (NCOA6/ASC2, KDM6A/UTX, PTIP, and PAGR1/PA1) (see below for full details) and, given their relationship to Kabuki syndrome (type 1 and 2) and type 2 Kleefstra syndrome, are discussed in greater detail below [24–26].