Genomic organization, mapping, and polymorphisms of the gene encoding human cartilage intermediate layer protein (CILP).

The CILP gene encodes a proform of two polypeptides. One of them, cartilage intermediate layer protein (CILP), is a non-collagenous protein recently isolated from human articular cartilage. The other is homologous to a porcine nucleotide pyrophosphohydrolase (NTPPHase) whose enzymatic activity is highest in articular tissue. The investigation reported here revealed that the CILP gene consists of nine exons spanning approximately 15 kb of genomic DNA on chromosome 15q22. We also report six single nucleotide variations in this gene; five of them cause amino acid changes and the most common of them substitutes isoleucine for threonine at codon 395.