Robin Trocki (born in 1956) is a 56 or 57-year-old actress who portrayed Jean Sylvester, Sue's older sister, on Glee. Like her character, Trocki has Down syndrome.
Trocki is a native of New Jersey and lives in Los Angeles. In addition to her work on Glee, she works in a bakery, takes karate lessons, and is a published writer. Her writing and art was published in the book Disabled Fables: Aesop's Fables, Retold And Illustrated By Artists With Developmental Disabilities.
In 2009, the Down Syndrome Association of Los Angeles honored her with her its "Voices" award.
In 2010, she and fellow Glee actress Lauren Potter received The Arc's Inclusion & Image Award for "breaking down barriers, increasing awareness and challenging stereotypes".
Trocki appeared as recurring character Jean Sylvester in five episodes of Glee during seasons 1 and 2. She was written off Glee after she developed advanced Alzheimer's during Season Two. 
Sue's baby, Robin Sylvester, is named after her.
Because of her condition she is expected to forget her role on Glee very soon. However, Jane Lynch and Lauren Potter took Jordyn (or baby Robin) to see Robin, to which she replied, 'I'm your aunt'.