Infantile spasms in a boy with an abnormal karyotype (46, XY, der(9)t(7;9)(p15;p22)pat).

Infantile spasm (IS) is an epilepsy syndrome affecting infants and young toddlers and many causes have been reported, including occasional chromosomal abnormalities. We describe a 6-month-oldboy who experienced his first seizure at 5 months of age. The seizures were characterized by brief head nods and forceful flexion of the trunk and limbs. The patient has been developmentally delayed since birth and had deteriorated remarkably in the last month. Interictal electroencephalography showed modified hypsarrhythmia. Magnetic resonance imaging showed delayed myelination and widened brain extracellular space. Chromosomal analysis revealed the karyotype 46, XY, der(9) t(7;9)(p15;p22) pat. His father has the asymptomatic reciprocal translocation t(7;9)(p15;p22). This chromosomal abnormality is probably the etiology for the ISs and severe developmental anomalies in this patient. Chromosomal analysis may be done in patients with IS with no obvious cause.