Modulates hedgehog signaling in several cell types including brain and lung through direct interaction with members of the hedgehog family. Interacts with all three hedgehog family members, SHH, IHH and DHH. The last 22 C-terminal amino acids may participate in cell membrane attachment. Widely expressed in fetal and adult tissues. Highest expression in adult heart, liver and pancreas, and in fetal kidney. A flexible loop interacts with the SHH zinc binding site and contributes to zinc binding. Genetic variations in HHIP define the stature quantitative trait locus 12 (STQTL12) [MIM:612224]. Adult height is an easily observable and highly heritable complex continuous trait. Because of this, it is a model trait for studying genetic influence on quantitative traits. Potentially soluble form. Belongs to the HHIP family. Truncated N-terminus.