In search for nAChR genes that may function in a diet-dependent manner, we screened mutants lacking nAChRs and found that the strain RB2355, which carries a deletion in the nAChR gene lev-1, manifested a severe developmental delay phenotype when fed HT115 but not OP50 (Fig 1A and 1B and see below). The gene discussed is CHRNA4; the disease is Global developmental delay.