Regarding the possible involvement of (other) rare heterozygous PCSK1 variants in obesity, to date, only one heterozygous PCSK1 variant (p.Arg80*, Grch38.p13 NM_000439.5:c.238C>T) was reported to co-segregate with obesity [34]. This evidence concerns the gene PCSK1 and obesity due to melanocortin 4 receptor deficiency.