MGI:109611Homozygous null mutants die by embryonic day E6.5 due to instability of desmosomes and tissue integrity; rescue by aggregation with wild-type tetraploid morulae increase embyronic survival with noted major defects in heart muscle, neuroepithelium and epidermis. Epidermis-specific conditional KO leads to compositionally altered epidermal desmosomes. Homozygosity for a specific point mutation is embryonic lethal while heterozygosity increases sensitivity to induced heart stress.