COL2A1, encoding the alpha-1 chain of type II procollagen, is crucial as type II collagen, composed of three identical alpha-1 chains, is the major component of cartilage. It is involved in the development and maintenance of articular cartilage, vitreous humour, inner ear, and nucleus pulposus [2,3]. Genetic models can help understand its functions in normal and disease-related biological processes.

Mutations in COL2A1 cause a variety of disorders. In Stickler syndrome type 1, over 90% of mutations are loss-of-function, predicted to result in nonsense-mediated decay. Vitreous anomalies, retinal detachments, cleft palate are common in patients with COL2A1 mutations [1]. In spondyloepiphyseal dysplasia, COL2A1 mutations lead to skeletal deterioration that occurs prior to the development of osteoarthritis. Heterozygous loss-of-function mutation of Col2a1 in male mice (Col2a1+/d) shows reduced cortical and trabecular parameters at 4 weeks, with osteoarthritis only detectable in 12-week-old mice [4].

In conclusion, COL2A1 is essential for the proper formation and function of cartilage-rich tissues. Mouse models, such as Col2a1+/d mice, have revealed its role in diseases like Stickler syndrome and spondyloepiphyseal dysplasia, helping understand the disease mechanisms related to COL2A1 mutations.