Introduction.

Intellectual disability is considered a global public health problem, the prevalence ranges from 1% to 3% of the world population, a figure whose genetic origin is estimated to be represented by 5-7% of subtelomeric syndromes. The objective of this research was to determine the frequency of intellectual disability of genetic etiology due to cryptic chromosomal rearrangements in 69 patients of IDAI.

Material and methods.

The descriptive cross-sectional study was carried out at the Institute of Genetics in 69 patients with intellectual disabilities from 5 to 18 years of age from the Institute for Child Adaptation (IDAI). The study was divided into three stages, the first consisted of preparing the genetic clinical history, then peripheral blood karyotyping was performed on all patients, finally, with suspected diagnosis, molecular cytogenetics was performed on nine of them, using a locus-specific probe.

Results.

43.48% of chromosomal rearrangements were found, 24.67% corresponded to cryptic syndromes, of these 7.25% responded to subtelomeric syndromes. Greater involvement was observed in the male population: men (65%) and 24 women (35%), obtaining a sex ratio of 1.88 in favor of the male sex.

Conclusions.

The genetic cause must be considered in all idiopathic intellectual disability, especially that due to cryptic chromosomal rearrangements. To confirm the diagnostic suspicion, classical cytogenetics and fluorescent in situ hybridization techniques are used, thus reaching a more precise diagnosis to assist in the genetic counseling of the patient.