One of Europe’s most powerful royal dynasties was so obsessed with securing its blue-blooded inheritance through family marriages that it brought about its own extinction through inbreeding, scientists have found.
Last Updated: 1:37PM BST 15 Apr 2009
The Hapsburgs ruled Spain from 1516 to 1700, presiding over the first global empire, but died out after generations of intermarriage, according to the first genetic analysis of the family.
The royal fashion of marrying relatives to preserve the dynastic heritage culminated in a monarch who was so genetically inbred that he was unable to provide an heir and power passed to the French Bourbons.
The dynasty was one of the most important and influential royal families in Europe – branches of the family ruled Austria, Hungary, Belgium, the Netherlands, the German empire and Spain.
Scientists have examined the family tree of the last of the Spanish Habsburgs, King Charles II, who died in 1700 at the age of 39, and discovered that, as a result of repeated marriages between close relatives, he was almost as inbred as the offspring of an incestuous relationship between a brother and sister or father and daughter.
The study found that nine out of 11 marriages over the 200 years were between first cousins or uncles and nieces, producing a small gene pool that made rare recessive genetic illnesses more prevalent.
Only half of the babies born to the dynasty during the period studied lived to see their first birthday, compared with about 80 per cent of children in Spanish villages at the time.
The study, published this week in the journal Public Library of Science One, indicated that Charles II suffered from two separate rare genetic conditions, which were almost certainly the result of his ancestors’ marriage patterns and which effectively assured that the dynasty died out with him.
Nicknamed El Hechizado (“the hexed”) because of his deformities, Charles II was not only inflicted with an extreme version of the Hapsburg chin, as immortalised in portraits by Titian and Velazquez, but his tongue was said to be so big for his mouth that he had difficulty speaking and drooled.
Historical accounts record that he also suffered from an oversized head, intestinal upsets, convulsions and, according to his first wife, premature ejaculation and his second wife, impotence.
“He was unable to speak until the age of four, and could not walk until the age of eight. He was short, weak and quite lean and thin,” said Gonzalo Alvarez, of the University of Santiago de Compostela, who led the study.
“He looked like an old person when he was 30 years old, suffering edemas [swellings] on his feet, legs, abdomen and face. During the last years of his life he could barely stand up and suffered from hallucinations and convulsive episodes,” he said.
The scientists concluded that medical problems of Charles II were not random but could be symptoms of two genetic disorders; an inherited thyroid deficiency, and renal tubular acidosis, a type of kidney failure that can cause metabolic problems.