Correction: Interplay of the Norrin and Wnt7a/Wnt7b signaling systems in blood–brain barrier and blood–retina barrier development and maintenance (Proceedings of the National Academy of Sciences of the United States of America (2018) 115 (E11827–E11836) DOI: 10.1073/pnas.1813217115)

The authors note that those instances of the term “GLUT1” that refer to Fig. 7 should instead appear as “CLDN5.” Specifically, all instances of “GLUT1” in the legend for Fig. 7 on page E11833 should instead appear as “CLDN5,” and all instances of “GLUT1” in the text starting from page E11831, right column, second full paragraph (“The Wnt7a/Wnt7b System Plays a Minimal Role in Retinal Vascular Development”) through to the end of page E11832 (to the end of the sentence ending “unaffected by the additional loss of Gpr124”) should be to “CLDN5.”