[A study on the occurrence of the deletion 22q11.2 in patients affected with a psychiatric disease].

AIM The aim of the study was an estimation of the rate of deletion 22q11.2 among psychiatric patients and an attempt at the assessment of the degree in which this rate is influenced by the coexistence of dysmorphic features and congenital defects. METHODS Cytogenetic examination was performed in 255 patients with psychosis. Patients were divided into two groups. Group I was composed of 61 patients with psychosis and at least two phenotypic features characteristic of 22q11.2 deletion syndrome (22q11DS), group II was composed of 194 patients with psychosis without phenotypic features of 22q11DS. Banding and fluorescence in situ hybridization (FISH) techniques were applied. RESULTS 22q11.2 deletion was found in 3/61 patients of group I (4.9%) and in 3/255 among all psychiatric patients (1.2%). This incidence was significantly higher than in the general population (p < 0.001). The frequency of the deletion was even higher among psychiatric patients revealing phenotypic features of 22q11DS: 3/61 (4.9%) (p < 0.0001). In all the cases with the deletion, the phenotype features were characteristic of 22q11DS. Three other psychiatric patients had sex chromosomes' aberrations: 47, XYY, 47, XXY and 47, XXX. Moreover one case of balanced translocation t(2;10) (q10; q10) was detected. Conclusions. (1) 22q11.2 deletion was found to be 40 times more common among psychiatric patients than in the general population; sex chromosome aberrations are also significantly more common than in the general population. (2) The presence of dysmorphic features and some congenital defects in psychiatric patients increases the rate of deletion 22q11.2 significantly.