I wrote about this about this basically 15 years ago

Confidentiality has been seen in the past as a fundamental ethical principle in health care and breaching confidentiality is usually a reason for disciplinary action. It has been assigned such a great value because it directly originates from the patient’s autonomy to control his or her own life […] Two types of re-identification are possible: the “Netflix” type and the “profiling” type.

There is a new Cell paper that builds a “profiling” attack using even single-cell gene expression data only

we demonstrate that individuals in single-cell gene expression datasets are vulnerable to linking attacks, where attackers can infer their sensitive phenotypic information using publicly available tissue or cell-type-specific expression quantitative trait loci (eQTLs) information.

So this should be included in informed consent forms also.