Cohesinopathies, including Cornelia de Lange syndrome and the overlapping phenotype SMC3, causing altered gene expression
Today’s post is in response to a request from a parent interested in a very rare genetic condition involving the SMC3 ( Structural Maintenance of Chromosomes protein 3) gene , it is cohesinopathy related to Cornelia de Lange syndrome , but really better considered a distinct condition. A cohesinopathy is a condition affecting the cohesin complex. This subject does get very complicated and requires a biology lesson. Mitosis Mitosis is the process where one cell produces an identical copy of itself and one becomes two. In the figure below consider the red chromosome; it has to become two red chromosomes and just before this occurs, you have two identical “chromatids” that are joined together at the “centromere”, like an “H” shape. The chromatids later separate and become two identical red chromosomes in two identical cells. In each cell there are two copies (here shown red and blue) of 22 chromosomes. In addition is the problematic X chromosome,...