Thus, knockout TRPV6–/– mice exhibit defective intestinal Ca2+ absorption, increased urinary Ca2+ excretion, decreased femoral bone mineral density, lower body weight, alopecia, dermatitis, and severely impaired male fertility15–19, whereas changes in TRPV6 expression have been shown in several mouse models of human diseases20–24. This evidence concerns the gene TRPV6 and alopecia.