I cannot provide a gene function summary for FDPS based on the provided abstracts. The PubMed abstracts supplied concern dental prosthetics and fixed dental prostheses (FDPs) outcomes, which are entirely unrelated to FDPS (farnesyl diphosphate synthase) gene function. None of the abstracts 12345678 contain information about farnesyl diphosphate synthase, isoprenoid biosynthesis, protein prenylation, cholesterol synthesis, or porokeratosis. To provide an accurate, citation-supported summary of FDPS gene function and its role in isoprenoid metabolism and disease, relevant molecular and clinical literature would be required.