Can missing DNA be replaced?

14 July 2014


Deon Davis says, “my daughter has a Wolf-Hirschhorn syndrome. It’s also referred to as "4p syndrome". As the name would suggest, the problem lies in the fact that some of her DNA is missing on the short - p - arm of the fourth chromosome, which delays her growth both physically and mentally. Is there a way to glue the missing part back on? My wife happens to have the missing part on her 3p arm because of a balanced chromosomal translocation.”


Dr. Sarah South, from the University of Utah,explains to Kat Arney whether missing DNA can be replaced...

Sarah:: The short answer is that it's not yet possible to do this for a couple of reasons. There has been some advances in the idea of restoring missing genes back to cells. But these advances have been primarily in situations where there is only a single gene that is not working or missing. We can use a harmless virus as a way of carrying that gene into some cells because viruses naturally have the ability to integrate the DNA they carry into their host cells. However, viruses can't carry the number of genes that would be missing in a patient with Wolf-Hirschhorn syndrome. Also, viruses only infect a subset of cells and for this condition, there are many different parts of the body that are affected and many different cells within the body that need to have these genes in order to function normally. Basically, we're not able to get the number of genes necessary into the cells and to target the number of cells that need to be targeted. The other problem is timing. In some genetic conditions, you may be able to introduce the genes back into those cells and yet, that may still not resolve the clinical symptoms. The clinical symptoms may be there because those specific genes were necessary at an earlier time of development such as during prenatal development.

Kat:: Thanks to our listener Deon Davis, Dr Sarah South and Harriet Johnson. And if you've got any questions about genes, DNA and genetics, just email them to me at

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