Evolution of DEE-SWAS into photosensitive epilepsy in a patient with an ASH1L gene mutation

To further describe novel clinical manifestations in patients with an <i>ASH1L</i> gene mutation and assess genotype-phenotype correlations for mutation variants in the <i>ASH1L</i> gene, a clinical case of a patient with an <i>ASH1L</i> gene mutation, cognitive development disorder, EEG changes with a SWAS pattern and subsequent development of photo-induced epilepsy is presented. A <i>de novo</i> mutation variant of the <i>ASH1L</i> gene, frameshift c.3971_3972delTT (p.Phe1324fs), was identified in a 7-year-old boy with intellectual disability, learning difficulties, and myoclonic seizures. A literature review identified the main «clinical core» of the pathological conditions associated with this gene mutation. In this clinical case, the development of DEE-SWAS syndrome in a carrier of a similar mutation, followed by transformation into photo-induced epilepsy, is described for the first time. It complements the known clinical characteristics of the disease and highlights the significance of this gene in the normal functioning of the nervous system. Mutations in <i>ASH1L</i> are associated with severe neurological disorders, autism spectrum disorders, and intellectual disability. This observation also suggests that <i>ASH1L</i> mutations may be associated with DEE-SWAS syndrome and photosensitive epilepsy.