Non-focal 4p16.3 deletions involving FGFRL1 have been reported in patients with Wolf-Hirschhorn syndrome (WHS) (MIM #194190) however this gene lies outside the current WHS critical region. Based on clinical studies, gene expression data, and studies of animal models, FGFRL1 was proposed as a candidate gene for certain aspects of the WHS phenotype [see PMIDs 18830230, 19056490, 19383940, 21792232], however haploinsufficiency for FGFRL1 alone has not been demonstrated. Furthermore, as deletions involving FGFRL1 have been reported in control populations [see DGV and PMID 21841781], additional studies will be necessary to determine the significance of FGFRL1 deletion.