Mutant embryos have alterations in embryonic morphology. No epidermal folds are found below the ventral nerve cord. Instead of stretching dorsally, the ectoderm appears to fold like an accordion in the anterior-posterior axis. As a consequence the gut is frequently pushed outside the embryo. By the end of embryogenesis the ventral folding of the epidermis pushes the ventral nerve cord further deep into the embryo. Beside the dorsal closure phenotypes, defects are also seen during head involution and in gut morphology. Mutant embryos also typically have fused commissure phenotypes where anterior and posterior commissures are not separated. Glial cell organisation is severely affected in mutants. Mutants have a significant increase in the number of midline glial cells.

In mutant embryos, commissures are fused but connectives are not affected. Embryos show a compacted phenotype with the dorsal edges remaining open for much longer than wild type. Dorsal closure does happen in the end. The PNS often shows defasciculating axons and an increase in the number of sensory neurons.