An early-onset X-linked PRA. Abnormal development of photoreceptors was recognizable as early as 4 weeks of age. The proportion of dying photoreceptors peaked at approximately 6 to 7 weeks of age and was significantly reduced after 12 weeks. XLPRA2 is an early-onset model of XLRP (1) that is characterized by abnormal photoreceptor maturation followed by progressive rod?cone degeneration and early inner retina remodeling. (Beltran et al. 2006) The X-linked inheritance means the risks of developing the disease effect males and females differently. Females who inherit the defective gene from one parent and a normal gene from another parent (carriers) won't be affected, but may have subtle defects that don't normally impact vision. Male pups who inherit the defective gene from the dams will be effected (there aren't male "carriers") Special breeding advice should be sought, if you are unfamiliar with X-link disease inheritance.