Dutch Prince Johan Friso, who doctors say may never regain consciousness following a serious avalanche accident, has always been seen as an outsider who chose his own path over royal protocol.

Prince Friso, 43, suffered serious injuries on being buried by an avalanche while skiing offpiste in Austria on February 17.

"It can't be said with certainty at this point whether Prince Friso will ever regain consciousness," Wolfgang Koller, head of the trauma unit at Innsbruck University Hospital, told a press conference Friday.

Nowhere was it clearer that the second son of reigning Queen Beatrix was different from his two brothers than when he went through with his marriage to Mabel Wisse Smit in 2004, a move that cost him his claim to the throne and his Royal House position.

According to Dutch law, royals need parliament's permission to marry with the request submitted by the premier on behalf of the Dutch cabinet.

But after it emerged that Johan Friso's future wife withheld details of her previous relationship with a Dutch drug baron, then prime minister Jan Peter Balkenende declined to ask parliamentary permission.

The prince nonetheless married Smit, who then became Princess Mabel, on April 24, 2004 in the the city of Delft's historic Oude Kerk, where some of the Netherlands' greatest heroes and scientists are buried.

But Johan Friso lost his claim to become Dutch king, a position for which he was fourth in line -- after his elder brother Crown Prince Willem-Alexander and his brother's three young daughters.

Allowed to keep his title as Prince of Orange-Nassau, Johan Friso took the decision in good humour, having always referred to himself as a "reserve pretender to the throne."

"He always went his own way," Dutch royal watcher Reinildis van Ditzhuyzen told AFP. "He never was that interested in the kingship anyway," she said.

"To be the head of state was never something that appealed to Friso's intellect," said historian Han van der Horst.

Johan Friso Bernhard Christiaan David was born to Queen Beatrix on September 25, 1968 in the central university city of Utrecht.

A gifted scholar, he excelled academically and studied mechanical engineering at the University of California-Berkeley before obtaining a degree in aeronautical engineering at the prestigious Delft Technical University.

He also holds a doctorate in business economics from the Erasmus University in Rotterdam.

Known for his dislike of the limelight, Johan Friso lives in London with Princess Mabel and their two daughters, Luana, 6, and Zaria, 5, for his professional career.

He has been chief financial director of Britain's URENCO group -- dealing with nuclear fuel supplies -- since 2011, and previously worked with the investment bank Goldman Sachs.

Since an early age, the prince enjoyed skiing in the exclusive Austrian resort town of Lech, where the Dutch royal family have been taking their winter vacations since the late 1950s.

The Christian daily Trouw called Friso "the Queen's favourite son, liked fast cars, golf, travel and diving. The type of man willing to take risks outside clearly marked pistes."

His drive for independence "is perhaps the reason why the prince was skiing on a slope where he perhaps should not have been," said historian Van der Horst.