Karyotype analysis in children with idiopathic intellectual disability

Intellectual disability 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 value of karyotype analysis as a first step test in children with idiopathic ID. Thirty-three patients with idiopathic intellectual disability were included in the study. 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 think that inv(9)(p12q13) is a benign variant. In conclusion, our findings showed that karyotype analysis was not helpful to determine etiology in children with idiopathic ID because of probably low patient number in our study.