Patricia Heathering

 (née Bancroft) was the wife of Gregory Magnus and mother of Helen Magnus.

Death
Chronology: Being that Helen's mother is never seen and very rarely spoken about, viewers are left to assume that Patricia had died while Helen was very young. Most likely at some point before Helen's supposed age of around ~15-years-old based on Patricia's lack of appearance in.

Last name
Continuity Error: In, as Helen is recounting facts to try to jog Charlie's memory of being her father Gregory Magnus, she states that he married a woman named "Patricia Heathering". Later in the series, during the last Will states that Helen's mother's maiden name was "Bancroft", not "Heathering". Many fans noticed this difference and wondered if the writer's simply forgot or overlooked the small detail.

According to Amanda Tapping, the reason behind this change may have potentially been due to a 'clearance issue', where the original name was once acceptable to say on television and then later it wasn't; forcing the show to edit the name.

Birthday
Chronology: In, when the Sanctuary team reaches the inner sanctum of the Bhalasaam labyrinth and stands around the central pedestal, Helen correctly guesses and inputs the numeral combination to unlock the instruction map for Gregory's tests for to perform in order to retrieve the hidden vial of source blood. Helen states that her father's favorite password is her mother's birthday.

The numbers seen entered in order are: 21836. Possible birthdays from that sequence include: (Speculation: As Gregory and Helen are both English, it could be the third option.)

Since Helen's birth date is known to be August 27th, 1850, it would mean that Patricia would have been 13-years-old when she got pregnant with her and 14-years-old when she gave birth to her.

Longevity
Due to the writers / creators discussing Gregory Magnus as not having Helen's longevity, him not aging as the result of cryo-preservation which was later retconned, changed to instead having gained longevity through scientific intervention while in Praxis, it indicates that Helen had inherited her ability from her mother. This means that Patricia herself was actually an abnormal, just with assumedly dormant genes; exactly like Helen had been before her exposure to the source blood in the Spring of 1886 which activated the trait.