It's been nearly 11 years since Madeleine McCann went missing, but her family isn't giving up hope she'll one day come home.

That includes Madeleine's younger twin siblings Sean and Amelie, who are using their 13th birthday wish to ask for their sister to return.

Madeleine was only three years old when she disappeared from the family's holiday apartment in Praia da Luz, Portugal in May 2007. She was allegedly kidnapped while her parents, Kate and Gary, were out to dinner with friends.

Despite Madeleine's disappearance being dubbed "the most heavily reported missing-person case in modern history," investigations have proven to be fruitless, as there have been no traces of the missing girl.

Despite the family's sorrow, their lives are still moving on.

The twins, who are aspiring athletes, were thrown a milestone birthday celebration as they marked their first day of being full-fledged teenagers.

But sadly, the occasion was still marked with melancholy.

"There will be prayers to remember Madeleine as well wherever she is. Kate and Gerry want to give the twins a memorable occasion, they're teenagers now and that's a big deal," a guest at the party told The Sun.

"But the party will be marred with a tinge of sadness because Madeleine is not here to join in the fun," the guest continued.

In a past speaking engagement for her charity Missing People, Kate said despite her family's busy life, they haven't stopped searching for the now 14-year-old girl.

"They have their own friends and they keep busy and they're really sporty but their only wish is for their big sister to come home. We miss our complete family of five," Kate said.

"As a family 98 per cent of the time we're busy. I don't know if that's a conscious thing but it helps. The urge to look for Madeleine absolutely hasn't changed at all," she added.

We are praying for Madeleine's safe return.