AUSTIN, Texas – A top Texas Democratic donor and Houston trial lawyer has died. Steve Mostyn was 46 years old.

Mostyn and his wife Amber have spent millions on Democratic campaigns and have long been considered the state's most powerful Democratic backers.

"Our family is heartbroken to confirm that after a sudden onset and battle with a mental health issue, Steve passed away Wednesday," Amber Mostyn said in a statement. “Steve was a beloved husband and devoted father who adored his children and never missed any of their sporting activities. He was a true friend, and a faithful fighter for those who did not have a voice,” she said. “If you or a loved one are thinking about suicide, or experiencing a health crisis, call the National Suicide Prevention Lifeline right now.”

The Chair of the Texas Democratic Party, Gilberto Hinojosa, said he was deeply saddened to have lost a dear friend.

“Millions of Texans live better lives because of the advocacy, philanthropy, and sheer willpower of Steve Mostyn," said Hinojosa. "Our state and our world are better because he fought so hard for us all."

The Mostyns also created the Mostyn Moreno Educational Foundation, a nonprofit that seeks to improve the lives of children with special needs.