The 52-year-old rapper took to social media Sunday night to announce his 29-year-old daughter had passed away.

"Our family is dealing with an overwhelming grief for the loss of my daughter Tytyana," Master P wrote on Instagram. "We respectfully request some privacy so that our family can grieve. We appreciate all of the prayers love and support."

He continued ... "Mental illness & substance abuse is a real issue that we can't be afraid to talk about. With God, we will get through this. #MyAngel."

Master P's son, and Tytyana's older brother, Romeo Miller also took to Instagram to mourn her death.

"Our family is dealing with an overwhelming grief for the loss of my little sister Tytyana. We respectfully request some privacy so that our family can grieve."

He went on ... "We appreciate all of the prayers, love, and support, and although this is sad times, I'm forever grateful for the memories I did have with my amazing sister. Love on your loved ones, life is short. The silver lining, I know she's in a way better place and finally at peace and free. God Bless. - RM"

The cause of death has not been revealed.

Law enforcement sources tell TMZ ... paramedics got an emergency call around 2:30 AM Saturday and responded to a home in the San Fernando Valley. It appears she was pronounced dead on scene -- she was not taken to a hospital.

Tytyana is one of MP's middle children -- she's also one of 4 daughters.

She's been featured on the family's reality show, "Growing Up Hip Hop," and her struggles with substance abuse have been well-documented ... including a dramatic moment where Romeo and P were encouraging her to enter rehab.

As for Tytyana, she had pursued an acting career, and appeared in "A Mother's Choice."

Tytyana was 29.