The clinical features of the patients were DD/ID, delayed speech, ADHD, behavioral abnormalities, short stature, low body weight, café‐au‐lait spots, metabolic abnormalities, and facial dysmorphism including coarse facial features, sparse hair, frontal bossing, hypertelorism, amblyopia, strabismus, and downslanted palpebral fissures, which expands the phenotype spectrum associated with TNRC6B deficiency syndrome. The gene discussed is TNRC6B; the disease is attention deficit-hyperactivity disorder.