48,XXYY in a general adult psychiatry department

The 48,XXYY syndrome is a distinct clinical and genetic entity, with an incidence of 1:17,000 to 1:50,000 newborns. Patients often access mental healthcare services due to behavior problems, such as aggressiveness and impulsiveness, and are frequently intellectually disabled. We report a case of a patient with 48,XXYY syndrome treated in a general adult psychiatry department. A 23-year-old man was frequently admitted to our inpatient psychiatric unit (14 admissions in five years) due to disruptive behavior, including self harm, aggression to objects and animals, and fire-setting behavior, in a context of dysphoric mood and marked impulsivity. Upon observation, the patient had mild intellectual disability, with prominent impulsive and aggressive features and very low tolerance to frustration. His physical examination revealed hypertelorism, increased thickness of neck, acne, sparse body hair, triangular pubic hair distribution, fifth digit clinodactyly, small testicles and penis, and gynecoid pelvis. Laboratory analysis revealed endocrine abnormalities (low plasma testosterone and subclinical hypothyroidism). Cardiac Doppler sonogram was normal. Electroencephalogram revealed only a diffuse slowing electrogenesis, with no etiological specificity. Clinical suspicion of a chromosomal disorder was confirmed by a 48,XXYY karyotype. Subsequent magnetic resonance imaging detected discrete bilateral reduction of the hippocampal formations, possibly related to temporal dysgenesia. Psychopharmacological treatment options met moderate success, with lack of adherence. Other psychosocial treatment interventions ensued, including family therapy and psychoeducation. We underscore the need to be alert for chromosomal disorders, even in a general adult psychiatry department, as a minority of patients may reach adult care without proper diagnosis.