Patrick Marin is the brother of Tom Marin, uncle of Hanna Marin, and son of Regina Marin. To date, he has only been mentioned, not shown.
Biograhpy
Regina's labor with Patrick was smoother and faster then it was with Tom, and Regina described it as, "he fell out faster then a gumdrop".
Series
Regina Marin, the mother of Patrick and his brother Tom, mentioned Patrick to her Granddaughter, Hanna Marin.