What's the difference between a chromosomal abnormality and a genetic disorder?
Genetic disorders are any mutations that occur in one of the 25,000 genes which can be located on the 46 chromosomes, found in each cell of the human body. Usually when we say "genetic disorder", we mean a "single-gene defect". That is, only 1 of the 25,000 genes are affected. A chromosomal abnormality on the other hand, affect an entire chromosome, or a substantial number of genes that make it up.
Numerical anomalies, as in an atypical number of chromosomes
Structural anomalies, in one or more chromosomes, including:
Missing portion of chromosomal DNA
Extra portion of chromosomal DNA
Irregular portion of chromosomal DNA
Usually occur where there is an error in cell division, following meiosis or mitosis
When the chromosome's structure is altered, it can be due to:
Karyotype (i.e. full set of chromosomes from a Pt) can be compared to a "normal" karyotype via genetic testing, to detect or confirm chromosome anomalies