The definition of a chromosome abnormality had evolved over the last 50 years as the technology to detect them has become more sophisticated and can detect smaller and smaller chromosome changes. Today a chromosome abnormality, or as they are now often called, a structural genomic variation or copy number variation, is the deletion or duplication of more than 50 base pairs of DNA. Chromosome 18 includes 80,373,285 base pairs of DNA.
Here is a picture of human chromosomes from a white blood cell. Anything you could do to this picture of chromosomes with scissors, glue and a copy machine can really happen and it does really happen. Most of these would not be survivable to birth but many are. The chromosome 18 abnormalities are some that are survivable. It is our goal that the lives of people with chromosome 18 abnormalities be healthy, happy, productive and long. After all, it is just biology. And if it is biology we can understand it and optimize it.
The chromosome 18 conditions are described in this video.
For more information about chromosome abnormalities see our other YouTube Videos.