Currently that is a far higher separation than you'll find in America in any group.
I am not aware of European royals having a high incidence of disability ~ maybe the Dutch Royals, but that's because they're stupid.
Revealed: the inbreeding that ruined the Hapsburgs
Dynasty that dominated Europe for more than 500 years was undone by incest, study finds
By Steve Connor
Wednesday, 15 April 2009
The Hapsburg dynasty was one of the most important and influential royal families in Europe dating back more than 500 years and producing rulers in Austria, Hungary, Belgium, the Netherlands and the German empire. Then, in 1700, it suffered a sudden demise of its Spanish branch. Now scientists believe they have come up with a definitive explanation.
A study of the extended family tree
of the House of Hapsburg has found that the last Spanish Hapsburg king, Charles II, was the offspring of a marriage that was almost as genetically inbred as an incestuous relationship between a brother and sister or parent and child.
In the European families, you had the two wings of the Hapsburgs: the Spanish and Austrian. The Spanish Hapsburgs intermarried...a lot. They eventually died out, with the last Spanish Hapsburg king dying in 1700 or so. Which led to the “War of Spanish Succession” when the French Bourbon king tried to place a relative on the Spanish throne. By the way, the last couple of Spanish kings were drooling idiots.
The Austrian Hapsburgs fared somewhat better, but not all that great. They very much frowned on marriage outside of their tribal clique, but to my knowledge kept the 1st and 2nd cousins apart.
Since Queen Victoria had a gob of kids and married them off to everybody but the Hapsburgs, and then those kids all had their kids marry each other, it’s no surprise the Battenburgs (now Windsors) had genetic problems. Czar Nicholas II married his 1st cousin, Alexandra of Hesse, a union that resulted in a hemophiliac male heir. Nicholas II was 1st cousin to King George V, grandfather of Elizabeth II. When they dug up the remains of Nicholas’ family, they sought as many close family members as they could for samples to confirm identity through DNA. Of course, they hit up the Windsors. You’d think they’d use Queen Elizabeth, since she was a direct descendant of a 1st cousin. Nope; her husband, Prince Phillip was used since he was considered a closer match.
Land and money is the only difference between Prince Charles and your stereotypical inhabitant of Appalachia.
CANTERBURY
Then hear me, gracious sovereign, and you peers,
That owe yourselves, your lives and services
To this imperial throne. There is no bar
To make against your highness’ claim to France
But this, which they produce from Pharamond,
‘In terram Salicam mulieres ne succedant:’
‘No woman shall succeed in Salique land:’
Which Salique land the French unjustly gloze
To be the realm of France, and Pharamond
The founder of this law and female bar.
Yet their own authors faithfully affirm
That the land Salique is in Germany,
Between the floods of Sala and of Elbe;
Where Charles the Great, having subdued the Saxons,
There left behind and settled certain French;
Who, holding in disdain the German women
For some dishonest manners of their life,
Establish’d then this law; to wit, no female
Should be inheritrix in Salique land:
Which Salique, as I said, ‘twixt Elbe and Sala,
Is at this day in Germany call’d Meisen.
Then doth it well appear that Salique law
Was not devised for the realm of France:
Nor did the French possess the Salique land
Until four hundred one and twenty years
After defunction of King Pharamond,
Idly supposed the founder of this law;
Who died within the year of our redemption
Four hundred twenty-six; and Charles the Great
Subdued the Saxons, and did seat the French
Beyond the river Sala, in the year
Eight hundred five. Besides, their writers say,
King Pepin, which deposed Childeric,
Did, as heir general, being descended
Of Blithild, which was daughter to King Clothair,
Make claim and title to the crown of France.
Hugh Capet also, who usurped the crown
Of Charles the duke of Lorraine, sole heir male
Of the true line and stock of Charles the Great,
To find his title with some shows of truth,
‘Through, in pure truth, it was corrupt and naught,
Convey’d himself as heir to the Lady Lingare,
Daughter to Charlemain, who was the son
To Lewis the emperor, and Lewis the son
Of Charles the Great. Also King Lewis the Tenth,
Who was sole heir to the usurper Capet,
Could not keep quiet in his conscience,
Wearing the crown of France, till satisfied
That fair Queen Isabel, his grandmother,
Was lineal of the Lady Ermengare,
Daughter to Charles the foresaid duke of Lorraine:
By the which marriage the line of Charles the Great
Was re-united to the crown of France.
So that, as clear as is the summer’s sun.
King Pepin’s title and Hugh Capet’s claim,
King Lewis his satisfaction, all appear
To hold in right and title of the female:
So do the kings of France unto this day;
Howbeit they would hold up this Salique law
To bar your highness claiming from the female,
And rather choose to hide them in a net
Than amply to imbar their crooked titles
Usurp’d from you and your progenitors.
...... Shakespeare, Henry V
I Couldn't give you specifics but the first thing that popped into my mind was the Hapsburgs.
The Hapsburg dynasty was pretty inbred.