Before he even knew Jenny was pregnant, Quentin ran off with his brother Edward's wife, Laura Collins to Alexandria, Egypt (728). When Jenny started showing signs of going mad, Edward got Judith Collins to make arrangements to have the children taken from her and raised by Mrs. Fillmore, a local woman. They told Jenny the children had died, which sent her completely over the edge of insanity and they locked her away in the Tower room which no one ventured near because of it's terrible history. Quentin was told Jenny had died (which he later discovered was untrue) and it was not until his son died from the curse Julianka placed on Jenny's sister, Magda Rakosi, that Quentin was informed of his children's existence.
It appeared Lenore was also going to die from Julianka's curse, but when Quentin and Aunt Magda showed up to try and cure her, her mother's spirit showed up and agreed to protect Lenore under the condition that Quentin never try to see her again (810).
Because Magda's curse on Quentin also included all his eldest male descendants, Lenore carried that curse to her children and grandchildren. Barnabas figured out that Lenore had no sons, but her daughter had two sons, Chris Jennings and Tom Jennings as well as a daughter, Amy Jennings. When Barnabas told Chris about Mrs. Filmore, Chris said that Lenore Filmore was his grandmother's name. Only Chris is affected by the curse because the curse only applied to the eldest son. Chris first underwent the werewolf transformation when he was in college (676).
As it was later revealed that Joe Haskell was a first cousin of the Jennings family, but had not inherited the curse, it is likely that Joe is a cousin on the Jennings side -- that is, Joe's mother was the sister of Mr Jennings, the father of Chris, Tom, and Amy, and was a Jennings before marriage, so Joe is no blood relation to the Collins/Filmore side.