PPP3R1 and learning disability: The calcium signaling pathway (KEGG ID: hsa04020) was significant (hypergeometric P = 0.023, FDR 0.19) due to ADRA1B, CHRM2, PPP3R1, and P2RX3. Another gene differentially expressed in patients with learning disorders, Synapsin 2 (SYN2), is a synaptic vesicle-associated protein that has been implicated in modulation of neurotransmitter release and in synaptogenesis.