48,XXYY syndrome was initially considered a variant of Klinefelter’s syndrome (1). Nowadays, it is accepted as a distinct clinical and genetic entity (2, 3). Individuals with this syndrome are more aggressive, more intellectually handicapped, and taller than people with Klinefelter’s syndrome (4). Children and adolescents with 48,XXYY syndrome often come to psychiatrists for behavioral problems, sometimes even before the chromosomal diagnosis is made. The incidences among newborn and institutionalized mentally retarded patients are 1/50,000 and 0.08%–0.33%, respectively (5, 6). Behavioral and intellectual disturbances in these patients are likely related to sex-chromosomal abnormalities (3). Clinical signs of 48,XXYY are generally nonspecific. Some of the common features include tall stature, gynecomastia, truncal obesity, skin ulcers, and a craniofacial dysmorphism described as a "pugilistic" facial appearance (7).