pediatrics
Overview of Chromosomal Abnormalities
Introduction
Chromosomal abnormalities cause various disorders. Abnormalities that affect autosomes (the 22 paired chromosomes that are alike in males and females) are more common than those that affect sex chromosomes (X and Y). Chromosomal abnormalities fit into several categories but broadly may be considered as numerical or structural. Numerical abnormalities may involve a part of, or the entire, chromosome. Numerical abnormalitiesinclude Trisomy (an extra chromosome) Monosomy (a missing chromosome) Structural abnormalitiesinclude Translocations (abnormalities in which a whole chromosome or segments of chromosomes inappropriately join with other chromosomes) Deletions and duplications of various parts of chromosomes 