Yumi Sekemoto

Yumi Sekemoto is the mother of Leighton Sekemoto, and the grandmother of Sam Sekemoto. At the start of the game, she is living with her son to help him raise his toddler, Sam. It is possible she is of Japanese descent. She probably adopted Leighton Sekemoto because he has no known father and they don´t share any similarities excluding the family oriented and perfectionist traits. Another thing that could of happened is the game makers put it in like that to cause a mystery or even like real life she was a single Mother also the Ivanov Family from Riverview and Grandma Kaminski and Nadine Ivanov.

Like a traditional granny she has the hair tied in a bun.

In The Sims 3 trailer she can be seen in the graveyard talking to the ghosts that inhabit it, as seen in the image below.