INFANTILE SPASMS ASSOCIATED WITH PROXIMAL DUPLICATION OF CHROMOSOME 15Q

We describe a case of infantile spasms associated with a chromosome ab normality (supernumerary inverted duplication of chromosome 15 [47, XX , +inv dup(15)]). The patient was nondysmorphic and presented with mil d hypotonia and delay in acquisition of gross motor milestones before the diagnosis of seizures at age 7 months. Additional features include d unilateral sensorineural deafness and torticollis. Molecular cytogen etic studies confirmed that the patient has a large inv dup(15). Inv d up(15) chromosomes are variable with respect to the size and genetic c omposition of the chromosome and in their phenotypic effects. Patients with small inv dup(15s) may have no phenotypic abnormalities, whereas patients with large inv dup(15s) may have multiple abnormalities. ACT H therapy resulted in prompt remission of seizures and resolution of E EG abnormalities. ACTH therapy resulted in prompt remission of seizure s and resolution of EEG abnormalities. This is the second report of a patient with IS and a supernumerary inv dup(15). Several genes code fo r neurotransmitter receptor subunits located in the duplicated region of chromosome 15, and abnormal dosage of these genes may be involved i n the genesis of seizure activity in carriers of the inv dup(15). Chro mosome analysis may lead to a specific diagnosis in infants with unexp lained infantile spasms.