LEPR and Alzheimer disease: Especially, 969 circRNA genes were significantly up- or down-regulated during adipogenic process and were classified as pattern I (AD-specific), represented by PTK2B [33], TGFBR3 [34], LEPR [35] and AEBP1 [36], whose host genes were key regulators of adipogenesis (Additional file 4: Table S3; Fig. 4).