Sequence-specific, AT-rich binding transcription factor which is part of a developmental regulatory system that provides cells with specific positional identities on the anterior-posterior axis. Binds DNA as a homodimer. Interacts with MEIS1, MEIS2 and MEIS3. Defects in Hoxa13 are the cause of hypodactyly (Hd), a condition characterized by profound deficiency of digital arch structures. Belongs to the Abd-B homeobox family.