Karyotype analysis in children with idiopathic intellectual disability.

Intellectual disability (ID) is a heterogeneous condition, affecting 1-3% of general population. In this study, karyotype analysis was performed in 33 children with idiopathic ID in a hospital with limited laboratory facilities to determine the value of karyotype analysis as a first step test in children with idiopathic ID. Thirty-three patients with idiopathic ID were included in the study. Giemsa-trypsin-Leishman (GTL) banding karyotype resolution at a standard resolution of 550 bands was performed to determine whether the patients had microdeletion/microduplication by using of conventional karyotype analysis. Of 33 children, seven (21.2%) showed various chromosomal changes. Polymorphisms including 46,XX,1qh+; 46,XX,1qh+,1qh+; 46,X,add(Y),q12; 46,XY,21ps+ and 46,XX,1qh+ were diagnosed in five children. Inversion [46,XY,inv9(p12q13)] and inversion and polymorphisms [46,XY,inv9(p12q13),13ps+] were diagnosed in two children, respectively. We believe that inv(9)(p12q13) is a benign variant. In conclusion, our findings showed that the karyotype analysis was not helpful to determine etiology in children with idiopathic ID, probably because of the low patient number in our study.