As an example, Grm7 knockdown leads to persistent abnormal neuronal development, while Grm7 overexpression ameliorates the defects in neurogenesis caused by Grm7 knockdown in mice.38 According to the functions of the marker genes of each subtype, these subtypes were named C1-Glycosaminoglycan Metabolic Disorder, C2-Collagen Metabolic Disorder, C3-Activated Sensory Neurons, and C4-Inflammation. Here, GRM7 is linked to metabolic disease.