So I read an article about a metabolic disease being treated with gene therapy, where they inserted corrective dna into the patient. https://www.independent.co.uk/news/science/dna-permanent-change-cure-disease-experiment-california-brain-madeux-iv-hunter-syndrome-a8055696.html
How can this be permanent though? Wouldn't the other cells "take over" these modified cells when they reproduce, and eventually have back the same old dna?
Furthermore, will this affect offspring in any way? Will they inherit the new dna changes (if that part of the dna is passed on from the parent with the changed dna)?