Chst5, also known as carbohydrate (N-acetylglucosamine-6-O) sulfotransferase 5, is involved in the sulfation of keratan sulfate chains. It plays a crucial role in matrix morphogenesis in collagen-rich tissues, especially in the cornea, by mediating the modification of keratan sulfate. It is also associated with pathways related to glycosylation and may have implications in cell adhesion and extracellular matrix remodeling [2,3]. Genetic models, such as mouse models, are valuable for studying its function.

In Chst5-null mice, the corneas are significantly thinner, lack high-sulfated keratan sulfate, and show abnormal chondroitin sulfate/dermatan sulfate proteoglycan complexes. The corneal stroma has widespread structural alterations in collagen fibrillar architecture, indicating that Chst5 is essential for proteoglycan biosynthesis and collagen matrix organization in the cornea [3]. Selective knockdown of wild-type Chst5 in mouse corneal endothelium induces experimental macular corneal dystrophy (MCD) with similar extracellular matrix synthesis impairments and corneal thinning as seen in MCD patients. Mice carrying Chst5 point mutation recapitulate clinical phenotypes of MCD along with corneal endothelial abnormalities [1].

In conclusion, Chst5 is vital for proper corneal development and function, as demonstrated by mouse knockout models. These models have revealed its role in macular corneal dystrophy, highlighting its significance in understanding the disease mechanism and potentially developing new therapeutic approaches for MCD [1,3].