ASXL3 De Novo Variant-Related Neurodevelopmental Disorder Presenting as Dystonic Cerebral Palsy

<i>ASXL3</i> loss-of-function variants represent a well-established cause of Bainbridge-Ropers syndrome, a syndromic neurodevelopmental disorder with intellectual and motor disabilities. Although a recent large-scale genomics-based study has suggested an association between <i>ASXL3</i> variation and cerebral palsy, there have been no detailed case descriptions. We report, here, a female individual with a de novo pathogenic c.1210C > T, p.Gln404* nonsense variant in <i>ASXL3</i>, identified within the frame of an ongoing research project applying trio whole-exome sequencing to the diagnosis of dystonic cerebral palsy. The patient presented with a mixture of infantile-onset limb/trunk dystonic postures and secondarily evolving distal spastic contractures, in addition to more typical features of <i>ASXL3</i>-related diseases such as severe feeding issues, intellectual disability, speech impairment, and facial dysmorphic abnormalities. Our case study confirms a role for <i>ASXL3</i> pathogenic variants in the etiology of cerebral-palsy phenotypes and indicates that dystonic features can be part of the clinical spectrum in Bainbridge-Ropers syndrome. <i>ASXL3</i> should be added to target-gene lists used for molecular evaluation of cerebral palsy.