POMCN1-ICD impairs eyelid development. (A–D) Photographs and H&E-stained paraffin sections of mouse eyes at E15.5. Arrowheads in A and C indicate the formation of fusion line between upper and lower eyelids. The eyelid of POMCN1-ICD remained open (arrows in B). (E–H) Photographs and H&E staining of mouse eyes at birth (P0). POMCN1-ICD causes incomplete eyelid closure. Arrowheads in E and G indicate the formation of a fusion line between upper and lower eyelids. Arrows in F and H indicate an eyelid closure defect. (I–N) Photographs and H&E staining of mouse eyes at P42. POMCN1-ICD exhibits an abnormality in the palpebral fissure. Arrowheads in M indicate the eyelid lavatory muscle which was not found in the POMCN1-ICD in N. Co, cornea; Le, lens; LL, lower eyelid; Re, retina; UL, upper eyelid.