COL1A2 and early-onset autosomal dominant Alzheimer disease: According to reports, type 1 collagen is an important component of bone matrix protein as well as arachnoid trabeculae and granules.51 Research has shown that osteoporosis is closely related to the genetic components of type 1 collagen, such as COL1A1 and COL1A2. 52 Meanwhile, a previous study found that brain atrophy in Alzheimer’s disease patients had a certain correlation with morphological changes in microvessels,53 while vascular smooth muscle is also composed of type 1 collagen to varying degrees.