TMEM39B and obesity due to melanocortin 4 receptor deficiency: SNP rs573901234 near gene JHDM1D-AS1 on chromosome 7 was associated with short sleep duration < 5 hours (p-value = 1.4×10−8), and five SNPs were associated with long sleep duration > 10 hours, among which rs74460673 at gene TMEM39B was previously found to be associated with BMI [25, 26] and rs573982927 at MYO3B was associated with obesity traits [27, 28] (Table 2).