Etiology of developmental delay in the pediatric population
Intellectual disability/mental retardation (ID/MR) is defined as incomplete mental and cognitive development present from childhood. There are number of pre-natal and post-natal risk factors that can cause ID/MR, but about 50% of all causes are genetic. ID/MR has prevalence of about 2% in the general population. Using standard cytogenetic methods analysis of chromosomes (GTG banding) and molecular genetic analysis for fragile X chromosome reveals only a small number of causes, but the use of new molecular genetic techniques has increased the rate of detection of subtle chromosomal aberrations, as well as the discovery of new candidate genes in etiology of ID/MR. These methods will improve the diagnosis and treatment of patients, as well as genetic counseling of parents.