FGFR1 and Hartsfield-Bixler-Demyer syndrome: In contrast, we predict 5 out of 5 variants in FGFR1 associated with Hartsfield syndrome (HRTFDS) to be deactivating, and inspection shows four very likely are, as they involve highly conserved active site residues such as glycines in the N-terminal Glycine-rich loop (p.Gly490Arg) or within the catalytic loop/HRD motif (p.Asp623Tyr, p.Arg627Thr, p.Asn628Lys).