• embryonic lethality increased progressively with time from E10.5 to birth

• varied penetrance of growth retardation with some mutants that where small at E10.5 and others that were normal in size

• failure of neural fold elevation and folding resulting in the failure of neural tube closure between the caudal border of the forebrain and the rostral border of the hindbrain

• increased apoptosis at E10.5 and abnormal patterns of cell proliferation in the ventral neuroepithelium that everts rather than elevates

• varied penetrance of growth retardation with some mutants that where small at E10.5 and others that were normal in size

• increased apoptosis at E10.5 and abnormal patterns of cell proliferation in the ventral neuroepithelium that everts rather than elevates

• varied phenotypic penetrance with some mutants exhibiting exencephaly at early times (E9.5 to E14.5) and others having normal skull closure (J:96957)

• 55% show exencephaly (J:114626)

• 16% exhibit open eyes at birth

• 100% exhibit spina bifida

• 100% show exencepahly

• 54% show open eyes at birth

• 100% exhibit curly tail

• 100% exhibit spina bifida

• exhibit an enhanced epidermis terminal differentiation defect than seen in single Grhl3 homozygotes

• skin shows impaired stratum corneum formation with most cells in the top of the epidermis containing nuclei; many cells show enlarged vacuolar-like structure not normally found in the granular layer

• the stratum corneum abnormality is primarily found at the anterior part of the embryo in the skin covering the head and upper body regions

• cornified envelopes are essentially absent