CYTOGENETIC AND MOLECULAR GENETIC EVALUATION OF GENOMIC REARRANGEMENTS IN CHILDREN WITH IDIOPATHIC INTELLECTUAL DISABILITY

Abstract

To identify the genetic cause of intellectual disability 130 study subjects were recruited and multiple assays were employed to screen the whole genome Severe intellectual disability was identified in 12 per cent of the subjects and 11 per cent were moderately disabled based on IQ evaluation A clinical evaluation of developmental delay was identified in 77 per cent of subjects Conventional cytogenetic analysis by high resolution GTG banding is a whole genome approach and revealed that 3 per cent of study subjects showed chromosomal abnormalities which were three deletions and one inversion PCR based screening of FMR1 gene mutations which are a characteristic feature of fragile X syndrome did not detect any mutations in the study population Subtelomeric rearrangements examined with FISH were detected at a frequency of 7.7 per cent and two balanced rearrangements were detected in the parental samples MLPA which was used to evaluate interstitial chromosomal rearrangements yielded a frequency of 2 per cent. No microdeletions or microduplications were detected using the QMPSF technique Though targeted and specialized techniques permitted the detection and delineation of more rearrangements phenotype and genotype correlation was not observed in a majority of the study subjects newline