Report of two cases of infantile spasms caused by a de novo deletion in the STXBP1 gene

Infantile spasms is one of the epileptic encephalopathies. These have a variety of established etiological factors, but in a subset of cases, the underlying cause is not evident despite extensive investigations. These cases are referred to as idiopathic or cryptogenic infantile spasms. We report on two cases where the etiology was established by high-resolution array-comparative genomic hybridization as a de novo deletion in the STXBP1 gene. We propose to include high-resolution array-comparative genomic hybridization as a part of the diagnostic evaluation program in patients with infantile spasms with an unknown etiology. Establishment of the etiology has important implications for prognosis and genetic counseling.