August 8, 2020

Sex between relatives caused the facial deformity of the Spanish kings of the 16th and 17th centuries | Science

Historian Jaime Contreras tells that the birth of Carlos II, on November 6, 1661, served as an excuse in Madrid to organize "a great mojiganga", a popular party with quirky costumes of animals and demons. “Hundreds of horoscope makers preached their predictions. Against what many feared, the best-known augurs assured that the Prince would become King. Most of the astral letters were enthusiastic: Saturn was the planet that sent its greatest effluvium, a star that was on the horizon of the court of Spain, without malicious aspects, ”said Contreras in his book Carlos II, The Bewitched (Today's topics). Very soon it was learned that the fortune tellers were wrong.

Carlos II – the last king of the Habsburgs, the Spanish branch of the Habsburgs – was born sickly. He acceded to the throne at age four, when he was a child with rickets and epilepsy that still sucked from his mother's chest. The secretary of the apostolic nuncio described like this to the young monarch when he was 25: “The king is rather short than tall, not badly formed, ugly in face; it has a long neck, a long face and as it hunched up; the lower lip typical of the Austrias (…). You cannot straighten your body except when you walk, unless you approach a wall, a table or something else. Your body is as weak as your mind. Occasionally it gives signs of intelligence, memory and a certain vivacity, but not now; It usually looks slow and indifferent, clumsy and indolent, looking dumbfounded. You can do with it what you want, because it lacks self-will. ”

Scientists have studied a family tree of 6,000 members from 20 generations of the Habsburgs

The geneticist Francisco Ceballos remembers an oil portrait of Carlos II with its characteristic protruding jaw, painted by Juan Carreño de Miranda around 1680. “It is not just mandibular prognathism. Carlos II had a very droopy nose, very droopy eyes, very droopy cheekbones. He had a maxillary deficiency and his entire face dropped, ”says the researcher. Ceballos is one of the 14 scientists who have just found a direct relationship between this typical Austrian facial deformity and inbreeding that they practiced for almost two centuries.

The parents of Carlos II, Felipe IV and Mariana of Austria, "were uncle and niece, but with the blood accumulated over the generations it was as if they were brothers, like an incest," explains Ceballos, of the University of the Witwatersrand, in Johannesburg (South Africa). Carlos II, recalls the geneticist, was the culmination of Austrias diplomacy, summarized in this Latin phrase: Bella Gerant Ali, Your Felix Austria Cloud ("Let others make wars. You, happy Austria, marry"). His strategy to dominate much of Europe were marriages between related members of different ruling families, with sex between cousins ​​or even between uncles and nieces.

A team of 10 maxillofacial surgeons has now diagnosed the degree of facial deformity of the Habsburgs thanks to 66 portraits of the monarchs, from Felipe I (1478-1506) to Carlos II (1661-1700), which are mainly preserved in the Museum of Prado and at the Museum of Art History in Vienna. Researchers have calculated the level of mandibular prognathism and maxillary deficiency and have confirmed for the first time what was already suspected: "an association between facial deformity and inbreeding." The greater the relationship between the parents, the greater disfigurement. The study is published this Monday in the specialized magazine Annals of Human Biology.

From left to right, geneticists Francisco Ceballos, Román Vilas and Gonzalo Álvarez, along with American artist Michelle Vaughan.

From left to right, geneticists Francisco Ceballos, Román Vilas and Gonzalo Álvarez, along with American artist Michelle Vaughan.

Florencio Monk, president of the Spanish Society of Oral and Maxillofacial Surgery and Head and Neck, has directed the diagnoses, made from oil portraits and supported by historical documents. Monk recalls the description of King Carlos V by his cosmographer Alonso de Santa Cruz: “His greatest ugliness was his mouth, because he had the teeth so disproportionate to the one above that the teeth were never found; of which two damages followed: the one to have the speech in a very hard way, his words were like beautiful, and the other, to have a lot of work in him; for not finding the teeth could not chew well. ”

"Consanguinity is a gateway to know the genetic architecture of a trait," explains Ceballos. A person receives two versions of each gene, one from his mother and one from his father. These two copies may be different, in which case the dominant variant will be expressed, the information of the other gene, called recessive, being masked. The results in the Austrias suggest that mandibular prognathism is a recessive trait that emerged in the monarchs because inbreeding marriages increased the chances of inheriting the two equally defective copies.

"Kings are a laboratory to study the effects of human consanguinity," says geneticist Francisco Ceballos

Ceballos and geneticist Gonzalo Álvarez, from the University of Santiago de Compostela, have been analyzing Austrias for more than a decade. In 2009, pointed out two genetic disorders, the combined deficiency of pituitary hormones and distal renal tubular acidosis, as the main culprits of the bad health of Carlos II, including his infertility, which led to the extinction of the dynasty. Scientists have studied a family tree of 6,000 members from 20 generations of the Habsburgs. If Felipe I had a consanguinity coefficient of 0.025, that of Carlos II was 0.25, which means that 25% of his genes were repeated, having received the same copy from his mother and father.

"Kings are a laboratory to study the effects of human consanguinity," says Ceballos, who is currently studying with his colleagues at the Bourbons to expand research. "King Alfonso XIII (great grandfather of Felipe VI) had a very clear mandibular prognathism," says Monje, who published the book in 2016 The sick face 50 universal paints to understand diseases of the face and neck.

"This new work on the Habsburg jaw suggests a pattern of recessive inheritance," says the geriatrician Georgina Martinón Torres, alien to this research and author of a doctoral thesis on old age in Velázquez's pictorial work. In the opinion of this doctor, the General University Hospital of Ciudad Real, genomic analyzes of people with prognathism will now be necessary to "ratify this suggestion."

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