Partial Rescue of TTD Cutaneous, Blood, and Developmental Phenotypes in Compound Heterozygous XpdTTD/†XPCS Mice (A) Photographs of 5-mo-old homozygous XpdTTD/TTD, compound heterozygous XpdTTD/†XPCS, and wt mice. Insets: images of first-round hair loss. (B) Histological analysis of the skin of XpdTTD/TTD, XpdTTD/†XPCS, and wt mice. TTD-associated acanthosis (thicker epidermis, indicated by solid vertical line), pronounced granular layer (indicated by arrows), and sebacious gland hyperplasia (indicated by dotted vertical line) were absent in the epidermis of XpdTTD/†XPCS and wt mice. Magnification 400×. (C) Cysteine content of hair from wt, XpdTTD/TTD, and XpdTTD/†XPCS mice. The p-value indicates significant differences between mutants and wt, as well as between XpdTTD/TTD and XpdTTD/†XPCS mice. Error bars indicate standard error of the mean (SEM). (D) Hematocrit values from blood of XpdTTD/TTD and XpdTTD/†XPCS mice. The p-values indicate the significance of the difference relative to wt. Error bars indicate SEM. (E) Body weights of developing XpdTTD/TTD and XpdTTD/†XPCS mice after weaning plotted as a percentage of the weight of age-matched control wt and heterozygote (hz) littermates (set at 100%). Error bars indicate SEM.