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

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