The race for the U.S. Senate in Pennsylvania took a deeply personal turn this weekened with sick children serving as political proxies in the national debate about health care in America.

U.S. Rep Lou Barletta, the Republican nominee, assailed U.S. Sen. Bob Casey Jr. for a "hurtful, insensitive" new campaign ad that struck close to home because his 18-month-old grandson is being treated with chemotherapy for cancer.

Casey, a Democrat from Scranton seeking a third term, put out three new campaign ads with supporters criticizing Barletta for a 2017 vote on legislation that would have allowed health insurance companies to charge customers much higher rates if they had pre-existing medical conditions.

One of the three ads featured Stacie Ritter of Manheim in Lancaster County, explaining the fear her family felt when her twin daughters were stricken with cancer.

"Thank God we had health insurance," Ritter says in the ad. "But if Lou Barletta has his way, kids like mine could be denied the care they need."

Barletta, the former mayor of Hazleton, took to Twitter on Sunday afternoon in an emotionally charged video, recounting how he told Casey and his wife a month ago about his grandson's medical condition. Barletta's grandson, Jordan, is also a twin.

"It's disgusting," Barletta said, appearing close to tears at the end of the 2-minute, 12-second video. "I'm ashamed. He should be ashamed. He's hurt my family. And the commercial should come down. Shame on him."

Casey's campaign was quick to point out that he has spoken about Ritter's family for years during the debate about the Patient Protection and Affordable Care Act, also known as Obamacare, and brought her up during a Senate hearing in January 2017.

"Congressman Barletta's votes have real consequences for Pennsylvania families like Stacie's," Casey said in a statement released by his campaign Sunday. "On Election Day, he will be held accountable for his record of voting to end protections for preexisting conditions for 5.3 million Pennsylvanians."

Barletta, like many Republicans in Congress, has voted periodically to overturn Obamacare, which was signed into law in 2010, the same year Barletta was running for his first term. That law offered protections for patients with preexisting conditions, preventing insurance companies from dropping their policies or denying them coverage.

This was long expected to be a line of attack for Democrats against Republicans in this midterm election. Casey's campaign went after Barletta on the issue when the four-term congressman declared his challenge in August 2017.

Barletta's campaign noted that he has supported GOP repeal legislation with protections for people with preexisting conditions.