WASHINGTON (Reuters) - Republican presidential candidate Rick Santorum's 3-year-old daughter, Isabella, who was born with a rare genetic disorder, has been hospitalized again, his campaign said on Friday.

"Rick and his wife Karen have taken their daughter Bella to the hospital. The family requests prayers and privacy as Bella works her way to recovery," campaign communications director Hogan Gidley said in a statement.

Bella suffers from the genetic disorder known as Trisomy 18, which often results in the death of a child. She had been hospitalized briefly in January with pneumonia.

Santorum, trailing Mitt Romney in the race for the Republican nomination, had planned to take time off from the campaign this week. He said Friday he would resume activities on Monday. His home state of Pennsylvania holds its presidential primary on April 24.

(Reporting By Charles Abbott; editing by Mary Milliken and Doina Chiacu)