17q21.31 Microdeletion associated with infantile spasms

Patients with 17q21.31 microdeletions frequently have neurologic abnormalities, especially seizures. This report is of a child with a deletion in this location who developed infantile spasms, a seizure type not specifically described in this syndrome. FISH analysis of parental blood metaphases demonstrated that the deletions occurred de novo. The deleted region encompasses the previously defined critical region for the 17q21.31 microdeletion syndrome, and includes the gene encoding for corticotropin-releasing hormone receptor 1, a protein implicated in hyperexcitability, and potentially in infantile spasms. Treatment with ACTH led to spasm cessation, consistent with its expected repression of CRH levels, which should be augmented by CRHR1 deletion, although this response was transient.