Enables heparan sulfate binding activity and heparin binding activity. Involved in ossification. Located in collagen-containing extracellular matrix. Human ortholog(s) of this gene implicated in Marshall syndrome; Stickler syndrome 2; autosomal dominant nonsyndromic deafness; and fibrochondrogenesis 1. Orthologous to human COL11A1 (collagen type XI alpha 1 chain). [provided by Alliance of Genome Resources, Apr 2022]