Question: Is it true that there are more than 6000 genetic diseases currently known for a humans to possibly get?

Daniela Lobo answered on 17 Jun 2016:

Hi Lucy,
First of all, I am really sorry for my late reply to your question! It is a very good question!

I honestly didn’t know the answer to that one, Lucy. So I had to look around for some answers. Here’s what I gathered.
No one really seems to know all the genes that make a human; actually, we don’t even know the exact number of genes in a human! I read somewhere that we have more genes “than a chicken and fewer than a grape”; isn’t it weird? So let’s say we have around 25000 genes. I think the list of possible genetic diseases is quite extensive (maybe 6000 is a good guess, I am not sure), but they are quite rare. They are normally characterised by mutations on a gene or on a chromosome – these mutations can be a deletion or insertion inside a gene, deletion of a whole gene, a whole chromosome that is missing or an extra chromosome that shouldn’t be there. For example, Down Syndrome or trisomy 21, is a genetic disease that happens because of an extra copy (so, a third copy) of the chromosome 21. These genome abnormalities are normally present since birth, and they may be hereditary (passed from the parents’ genes) or it might be a new mutation and change to the DNA that caused the defects (environmental cause). Genetic diseases are related to some cancers, heart diseases, muscular diseases, blood diseases, respiratory diseases, … the list is vast!

Does this answer your question, Lucy?