John Gill's  Exposition of the Bible 

Genesis 46:17

And the sons of Asher; Jimnah, and Ishuah, and Isui, and Beriah, and Serah their sister: and the sons of Beriah; Heber, and Malchiel.

And the sons of Asher,.... Another son of Jacob by Leah's maid Zilpah, whose sons were,

Jimnah, and Ishuah, and Isui, and Beriah, and Serah their sister; who is called Sarah, Numbers 26:46, and by the Septuagint here. She seems to have been a person of some note, being so particularly remarked in both places:

And the sons of Beriah, Heber and Malchiel; this Beriah seems to be the youngest son of Asher, and yet had two sons; who, as the Targum of Jonathan adds, went down into Egypt; he must marry, and have sons when very young; the thing is not impossible: See Gill on "Genesis 46:12";