Sequence-specific transcription factor which is part of a developmental regulatory system that provides cells with specific positional identities on the anterior-posterior axis. Acts on the anterior body structures. The two common alleles; HOX1B*A and HOX1B*B have a frequency of 78.8% and 21.2% respectively. The disease is caused by variants affecting the gene represented in this entry. Belongs to the Antp homeobox family. Labial subfamily.