Under the assumption that phenotypes belonging to top-level HPO abnormalities (i.e., musculoskeletal, growth, digestive, respiratory, etc.)not covered by an existing knowledge base, such as Orphanet, would have a higher chance to represent real hallucinations, we sampled and manually reviewed 130 entries (10%) from a total of 1,300 entries generated by the 2 commercial LLMs in the context of the Orphanet genetic diseases. This evidence concerns the gene GFER and hereditary disease.