The second patient (Patient 2) carrying a novel heterozygous SIM1 variant (p.Q36X, c.106 G>T in exon 1), was five years old, her birth weight was 2300 g, her BMI-SDS was 4.7 and she had severe obesity from two years of age. This evidence concerns the gene SIM1 and obesity due to melanocortin 4 receptor deficiency.