In patients with osteogenesis imperfecta type VI, a disease characterized by low bone mass and reduced bone strength, a homozygous frame-shift mutation in exon 4 or a termination mutation in exon 8 in the SERPINF1 gene is detected, resulting in undetectable levels of PEDF protein in the circulation [28]. Here, SERPINF1 is linked to osteogenesis imperfecta.