22q13.3 Deletion Syndrome: An Underdiagnosed Cause of Mental Retardation

Abstract

Phelan-McDermid syndrome, also known as 22q13.3 deletion syndrome, is characterized by global developmental delay, absent or delayed speech, generalized hypotonia, and minor physical anomalies. The deletion typically involves the terminal band 22q13.3 and has been associated with both familial and de-novo translocations. We report the case of an 11-year-old Turkish girl with 22q13.3 deletion syndrome presenting with repeated seizures during the course of a rubella infection. We also review the clinical features of 22q13.3 deletion syndrome and emphasize the importance of considering a rare microdeletion syndrome for idiopathic mental retardation when results of a routine karyotype analysis are normal. To the best of our knowledge, this is the first reported case of a Turkish patient with isolated 22q13.3 deletion syndrome.