GAD1 and progressive pseudorheumatoid arthropathy of childhood: Moreover, the directionality of expression differences (GAD1 being downregulated and UNC13B being upregulated in PPD) was in line with existing hypotheses that ALLO’s dramatic decline at parturition triggers PPD symptoms by critically decreasing inhibitory signaling, thereby further exacerbating already dysregulated excitatory neurotransmission [14].