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Background. Heterozygous pathogenic variants in the <i>DDX3X</i> gene account for 1–3% of females with intellectual and developmental disabilities (IDD). The clinical presentation is variable, including a wide range of neurological and behavioral deficits and structural defects of the brain. Approximately 52% of affected females remain nonverbal after five years of age. Case presentation: We report a 7 year old nonverbal female with a likely novel de novo pathogenic heterozygous variant in the <i>DDX3X</i> gene affecting the non-canonical splice-site in the intron 1 (NM_001356:c.45+12G>A). The patient presents with features typical for the <i>DDX3X</i> phenotype, such as: movement disorders, behavioral problems, a diagnosis of autism spectrum disorder (ASD), and some other features uncommon for <i>DDX3X</i> such as: muscle hypertonia and spinal asymmetry evaluated through the scoliometer. Conclusions. Due to its rare occurrence, the clinical picture of <i>DDX3X</i> syndrome is yet to be fully determined. So far, behavioral disorders, including those from ASD, and neurological abnormalities seem to be the dominant features of this disorder.