We report a 2 year-old boy with a background history of Ohtahara syndrome due to a missense variant in ARX (the aristaless-related homeobox gene) who subsequently developed status dystonicus.
Reviewing records of patients with ARX mutations, infantile epilepsies, and psychomotor retardation, we analyzed a family harboring a novel ARX mutation with different phenotypes in males and females, including Ohtahara syndrome.
This study confirms that ARX is involved in the pathogenesis of cryptogenic early onset epileptic encephalopathy, such as OS, and suggests that the severity of the electroclinical picture is likely to not exclusively correlate with the extent of expansions of the polyalanine tracts, but rather with the functional effect of different pathogenetic mutations.
ARX mutation testing should be undertaken in children aged less than 1 year with Ohtahara syndrome and a movement disorder, and in infants with unexplained neurodegeneration, progressive white matter loss, and cortical atrophy.
The etiology of Ohtahara syndrome is heterogeneous; however, the molecular analysis of ARX should be considered in sporadic or familial male patients with Ohtahara syndrome.
A longer polyalanine expansion mutation in the ARX gene causes early infantile epileptic encephalopathy with suppression-burst pattern (Ohtahara syndrome).