GAD1 and omphalocele: For GABA, GAD67 is the major GAD isoform in utero and GAD67 knockout mice exhibit marked ~90% loss of GABA [119], displaying cleft palate (~75%) and defects in the abdominal wall (omphalocele, ~45%) [119], while GAD65 knockout mice exhibit only modest ~20% GABA loss with no birth or growth abnormalities [120,121].