Concerning the single impacted FGFR1 domains, a mutational distribution could be disclosed, with most variants afflicting the TK domain (Supplementary Table S1 and Figure 4), suggesting that kinase-specific variants lead to the multisystem manifestations of HRTFDS, as previously demonstrated [16]. Here, FGFR1 is linked to Hartsfield-Bixler-Demyer syndrome.