The NF1 group showed faster saccadic reaction times than all other groups [FH-ASD: t(465) = 2.42, p = 0.02, CI = 0.12 to 1.18; FH-ASD + ADHD t(465) = 3.66, p = 0.003, CI = 0.56 to 1.85; FH-ADHD t(465) = 2.81, p = 0.005, CI = 0.27 to 1.52] and a slower developmental improvement than other groups with a family history of ADHD [FH-ASD + ADHD: t(545) = −2.89, p = 0.004, CI = −0.004 to −0.001; FH-ADHD: t(546) = −2.53, p = 0.01, CI = −0.004 to −0.001], but not those with a family history of ASD only [FH-ASD: t(546) = −1.77, p = 0.08, CI = −0.003 to 0]. The gene discussed is NF1; the disease is attention deficit-hyperactivity disorder.