APOC1 and obesity due to melanocortin 4 receptor deficiency: On the other hand, sphingomyelin underrepresentation, together with the enrichment of hexosylceramides paralleling reduced linc-GALNTL6-4 expression, may be related to the catalytic activity of APOC1, which includes the cleavage of sphingomyelins to generate ceramides [69], contributing to some of the most common sequelae of obesity [70].