Chromosome Polymorphism and Human Pathology: About 27 Cases of Chromosome 9 Inversion in the Beninese Population

The chromosomal polymorphism defined by variations of some chromosomal regions of a person (the constitutive heterochromatin and the short arms of the acrocentric chromosomes (13 to 15 and 21 -22)) sometimes highlighted problems with regard to their safety and their pathogenicity.Polymorphisms are usually found in the same family and transmitted in the dominant Mendelian.Chromosome 9 inversion is a frequent phenomenon that some cytogeneticists consider as a variant of normal.Despite its classification as a minor chromosome rearrangement which does not correspond to abnormal phenotypes, many reports have raised conflicting opinions as well, and its complete safety is controversial.27 cases of inversion of chromosome 9 were identified in our laboratory.The main indications for karyotype of the case of inv (9) were congenital cardiopathy (18.5%), sex development disorders of (18.5%), down syndrome (18.5%), and infertility (14.8%).This study stood out the observations of many authors who highlighted the involvement of inv (9) in the genesis of several pathologies.