Ourlead 5-SAT FPT (Table 1) is an agonist at 5-HT1A, 5-HT1B, and 5-HT1D receptors44 thatreduced repetitive behaviors and spontaneous seizures as wellas increased prosocial behaviors in a mouse model of fragile X syndrome,45 the most common monogenetic form of autism spectrumdisorder; moreover, FPT was orally active and did notcause sedation.46 The contribution of each5-HT1 receptor subtype regarding FPT preclinicalneurotherapeutic activities is unknown, however, and FPT has other receptor activities.47−49. Here, HTR1B is linked to fragile X syndrome.