If the grandmother has 50 dolls, Rene's sister, who has 2 more dolls than their grandmother, has 50+2 = <<50+2=52>>52 dolls.
Together, Rene's sister and the grandmother have 52+50 = <<52+50=102>>102 dolls.
Since Rene has three times as many dolls as her sister, she has 52*3 = <<52*3=156>>156 dolls.
Altogether, they have 156+102 = <<156+102=258>>258 dolls.
#### 258