Gain-of-function mutations in AFF4, encoding a subunit of the SEC, result in the CdLS-related CHOPS (OMIM# 616368) (Cognitive development and coarse facies, Heart defects, Obesity, Pulmonary involvement, and Short stature and skeletal dysplasia) syndrome (Izumi et al., 2015). Here, AFF4 is linked to obesity due to melanocortin 4 receptor deficiency.