The previously described MHO phenotype of LFABP null mice, characterized by normal glucose and insulin levels as well as decreased hepatic steatosis [3] and resistance to obesity-induced decrease in exercise capacity [4], is further corroborated in the present study, where we show a highly unusual hyperplastic mode of subcutaneous fat expansion. This evidence concerns the gene FABP1 and obesity due to melanocortin 4 receptor deficiency.