West syndrome in a patient with balanced translocation t(X;18)(p22;p11.2)

We describe a case of West syndrome with the balanced translocation t(X;18)(p22;p11.2). Treatment with high-dose vitamin B6, adrenocorticotropic hormone, thyrotropin-releasing hormone, and antiepileptic compounds was not effective, and the patient exhibited persistent refractory seizures and severe developmental delays. Although no mutation analysis and X chromosome inactivation were performed, we suggest that the chromosomal abnormality in the present patient is the main etiologic factor responsible for the infantile spasms and severe developmental delay.