It appears that Mordecai ben Moshe's son Kalonymos had a daughter Barucha (spelled many ways including Brucha or Bracha). She married Rabbi Eliyahu Kagan and that began the Kagan rabbinical dynasty of Lithuania. I am a descendant of that dynasty through the Rubin family of Rezekne, Latvia. (And by the way, the Kukla family has no relation to this lineage.)
If anyone has more information on those lines, please contact me.