SPARC and obesity due to melanocortin 4 receptor deficiency: Cluster 4 includes a number of genes with roles in regulation of cell and tissue size and shape, many of which are linked to adipose tissue expansion in obesity (ENPP2, EGFL6, RASA1, SPARC, ANXA2, SNTB2, IFT81, DIAPH2, SGCD, ATP10A, LOXL4, ATG14 and ARHGEF7).