Chromosomal fragile sites (CFSs) are loci or regions susceptible to spontaneous or induced occurrence of gaps, breaks and rearrangements. In this work, we studied the data of 4535 patients stored at DECIPHER (Database of Chromosomal Imbalance and Phenotype in Humans Using Ensembl Resources). We mapped fragile sites to chromosomal bands and divided the 23 chromosomes into fragile and non-fragile sites. The frequency of rearrangements at the chromosomal location of clones found to be deleted or duplicated in the array/CGH analysis, provided by DECIPHER, was compared in Chromosomal Fragile Sites vs. non-Fragile Sites of the human genome. The POSSUM Web was used to complement this study. The results indicated 1) a predominance of rearrangements in CFSs, 2) the absence of statistically significant difference between the frequency of rearrangements in common CFSs vs. rare CFSs, 3) a predominance of deletions over duplications in CFSs. These results on constitutional chromosomal rearrangements are evocative of the findings previously reported by others relatively to cancer supporting the current line of evidence and suggesting that a common mechanism can underlie the generation of constitutional and somatic rearrangements. The combination of insights obtained from our results and their interrelationships can indicate strategies by which the mechanisms can be targeted with preventive medical interventions.