Albert Barnes Commentary 1 Chronicles 3:19

"And the sons of Pedaiah: Zerubbabel, and Shimei. And the sons of Zerubbabel: Meshullam, and Hananiah; and Shelomith was their sister;" — 1 Chronicles 3:19 (ASV)

Zerubbabel, who is elsewhere always called “the son of Shealtiel,” was only Shealtiel’s heir and legal son. He was, in fact, his nephew—the son of his brother, Pedaiah.