Medical genetic testing, ‘next generation sequencing’, is increasingly generating data that could become useful for patients after they have been discharged from care. If new information is discovered that links a disease to a specific mutation, do health professionals have a legal duty to recontact their patients? Apart from other concerns (such as respecting the patient’s right not to know), in many cases, this would require re-evaluation or re-analysis of the data. Taking such issues into account, we conclude that, at least at this point in time, it is not arguable that there is an unconditional duty of this kind. Health professionals should always do what can be reasonably expected from them to do justice to the patient’s right to information. When there is reason to believe that recontacting would be of significant clinical relevance for the patient, they should do so, unless efforts and costs involved would be disproportional.