Intelligence disorder or developmental delay is the defect of cognitive function and social adaptation function as the main clinical features, two-thirds of the etiology is unknown.Clinical manifestations, high morbidity, and low treatment outcome are the major challenge for us.In recent years, with the application of the new generation of sequencing technology, We have gained further understanding of the etiology and pathogenesis of intelligent disorder or developmental delay.It has been found that multiple copies of chromosomal copies can lead to it.This paper summarizes the clinical, imaging and etiology of intelligent disorder or developmental delay, especially the recent advances in molecular genetics.

Developmental delay; Etiology; Mutation