The first phrase in the first verse to Isaiah 49 has been deleted from the King James Version but has been retained in the Brass Plates version contained in the Book of Mormon. It is not unexpected that this phrase was deleted from the Bible version, as it identifies the wickedness of Israel's pastors as the reason for the scattering of Israel. Interestingly enough, this phrase comprises a very neat chiasmus.
4] And again: Hearken
3] O ye house of Israel,
2A] all ye that are broken off
2B] and are driven out
1] because of the wickedness of the pastors of my people
2A] yea, all ye that are broken off,
2B] that are scattered abroad,
3] who are of my people, O house of Israel.
4] Listen,
If this sophisticated literary jewel were a spurious addition by Joseph Smith rather than a purposeful deletion by the Biblical scribes, it would require the admission of a literary genius on the part of the Prophet that would be as difficult to explain as his ability to translate by the gift and power of God. [H. Clay Gorton, The Legacy of the Brass Plates of Laban, pp. 60-61]