What happened to Masaki's family? In Bleach, Ichigo's mother Masaki


  was a quincy and was living with Uryuu's father, Ryuken Ishida as a teenager.


She was the last of the Kurosaki line. What happened to her family? How did they die?
It hasn't been told in manga yet. We can only speculate. 

The Great Quincy War can't be the reason as it happened 200 years ago. We can safely presume they died of natural causes and also they were Echt Quincies (pure-blooded Quincies who refuse to marry and mate with anyone but a pure-blooded Quincy and who were almost extinct after the Great Purge).