The classical features of LS are: (1) short stature (−4 to −10 SDS below the median normal height); (2) typical face and reduced head circumference; (3) obesity; (4) acromicria (i.e., smallness of the extremities); (5) high basal serum GH; and (6) low to undetectable serum IGF1, without response to exogenous GH [29]. This evidence concerns the gene IGF1 and obesity due to melanocortin 4 receptor deficiency.