Homozygotes do not survive to adulthood at 18 or 25oC. At 25oC, the survival rates of homozygotes are: eclosion - 2%, pupation 8%. At 18oC, the survival rates of homozygotes are: eclosion - 2%, pupation 5%. Ptp69D8 embryos show motor axon defects; 30% of ISNb axons, 9% of ISN axons, 14% of SNa axons and 12% of SNc axons show defects.