PCDH11X and obesity due to melanocortin 4 receptor deficiency: Investigating the exome sequencing data of 30 extremely obese subjects (BMI 45–65 kg/m2) shows that predicted damaging missense variants in olfactory receptor genes on chromosome 1q and rare predicted damaging variants in the protocadherin (PCDH) beta-cluster genes on chromosome 5q31, reported in our previous work, co-localize in subjects with extreme obesity.