[Developmental and epileptic encephalopathy 33 caused by gene mutation: a case report].

A boy, aged 7 months, presented with severe global developmental delay (GDD), refractory epilepsy, hypotonia, nystagmus, ocular hypertelorism, a broad nasal bridge, everted upper lip, a high palatal arch, and cryptorchidism. Genetic testing revealed a heterozygous missense mutation of c.364G>A(p.E122K) in the gene, and finally the boy was diagnosed with autosomal dominant developmental and epileptic encephalopathy 33 caused by the gene mutation. This case report suggests that for children with unexplained infancy-onset severe to profound GDD/intellectual disability and refractory epilepsy, genetic testing for gene mutations should be considered. This is particularly important for those exhibiting hypotonia, nonverbal communication, and craniofacial deformities, to facilitate a confirmed diagnosis.