However, for successful treatment of LS, further improvement is needed to express mGHR to extra-hepatic tissues using ubiquitous promoters/enhancers such as CAG (CMV enhancer/chicken beta Actin promoter/rabbit beta-Globin intron) promoter to target its expression to more tissues, especially to adipose tissue to prevent obesity [44], as well as growth plates for normal elongation of the bone [39]. Here, HBB is linked to obesity due to melanocortin 4 receptor deficiency.