Since birth, Anji and Nelly Polanco have suffered from cystinosis — a rare genetic disease that primarily affects children, according to a report in The Chicago Sun Times.

The disease causes the amino acid cystine to accumulate in various organs of the body and caused the twin's kidneys to fail.

This week, the two underwent simultaneous kidney transplants.

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On Wednesday morning the twins' mother, 27-year-old Rachel Dalomba, received a call that two suitable kidneys from a donor, who was killed in an automobile accident, were available for the 10-year-olds.

By that afternoon, the girls were being taken into the operating room at Children's Memorial Hospital in Chicago where doctors performed the transplant surgery.

"They're doing great," Dr. Riccardo Superina, who performed the four-hour operation Anji, told the Sun Times. "Blood tests indicate the kidneys are working. We expect that with each passing day, kidney function will return rapidly back to normal."