16 Royals Who Suffered From Hereditary Mutations And Defects Caused By Inbreeding

Getting married to a cousin or someone who is biologically related has been one of the most prominent acts of the royal families since numerous dynasties. This act was termed Consanguinity. The main idea behind marrying a relative is to ensure genetic purity by producing children within the family bloodline. 

The royal families were unwilling to share the power of their dynasty, exposing themselves to deadly congenital disabilities.

The European royal dynasties are infamous for maintaining human inbreeding. These marriages represented extreme kinship resulting from the matrimonial policy of the dynasty to establish political alliances through marriage. 

Brother-sister and parent-child marriages were common in the ancient royal dynasties of the Egyptian pharaohs and the Persian dynasty.

These types of highly close inbreeding suffer from several limitations, such as uncertain pedigrees. Due to proper documentation, some total sibling marriages are still controversial in the most recent Egyptian royal families. 

However, the genealogical records and mortality-fertility data in the European dynasties are much more extensive, providing a valuable framework for human inbreeding research.

In humans, some studies display the populations with higher rates of inbreeding, leading to lower inbreeding effect on pre-reproductive mortality and eventually eliminating deleterious alleles in different inbred populations. 

This process is likely to cause temporal changes leading to inbreeding depression, primarily detected in the European royal dynasties.

Here is a list of 16 royals who had to suffer from hereditary mutations and defects caused by inbreeding are listed below:

What was the most prevalent disease in many royal families following inbreeding?

Queen Victoria supposedly passed down a Hemophilia B throughout the European royal families. This lineage led to the disease being known as “the royal disease.”

Who is the most inherent person in the world?

Charles II, also known as “the bewitched,” is the most inbred royal, with an inbreeding coefficient of 25, equivalent to the offspring of two siblings. He had an overly large tongue, epilepsy, and other illnesses.

16. The massive, drool-secreting tongue of Spain’s Charles II

A painting of Charles II of Spain
A painting of Charles II of Spain

The Habsburgs were considered prominent families in Europe for over a century. Their bloodline, which started around the 13th century, continued ruling until the 1900s through Spain, the entire Empire of Rome, and Austria.

This dynasty followed consanguineous marriages for so long that Joanna of Castille, one of Charles’s ancestors, appeared fourteen times in their family tree.

Their line, however, suffered from massive inbreeding leading to the dynasty’s fall. This family has an oversized jawline and a large Habsburg jaw tongue, making eating and speaking difficult. It is also known as mandibular prognathism, causing excessive drooling.

Charles II, known as the bewitched, looked the part especially; he was highly inbred. The quotient of his inbred counted more than any other siblings were to be married, including his parents.

He was severely developmentally delayed, manifesting as not walking until the age of eight, and could only walk with incredible difficulty. 

Similarly, he was impotent and left no one to look after his throne. This brought an end to the rule of the Hashburg family in Spain.

15. The massive head of Ferdinand I of Austria

A painting of Emperor Ferdinand I of Austria
A painting of Emperor Ferdinand I of Austria

Ferdinand I of Austria, born t Joana os Castle in 1793, had hydrocephalus. A rare condition where a person is at risk for brain damage due to the amount of brain water that puts pressure on the body’s sensitive tissues.

If not brain damage, this could cause the head size to be enormous and imbalance other body parts.

Ferdinand also had epilepsy, all caused due to the inbreeding of his parents.

There was no suitable treatment for his condition, making him limited to physical activities so much that he could not pour himself a glass of water, open a door, or climb stairs unaided. 

Some authors, however, claim that Ferdinand I had artistic talents and was interested in the natural sciences and technical innovations. His linguistic gifts are highlighted because he can speak five different languages.

As the firstborn son, Ferdinand I was confirmed as the successor to his father’s throne. At age twenty-five, he was regarded as the crown prince when he made his first public appearance as his father’s official representative. 

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He liked to sit down on the open end of a wastepaper basket and roll around on the floor during his reign. To everyone’s surprise, he held the throne for eighteen years, resigning to his nephew Francis Joseph.

He married his distant relative Maria Anna of Piedmont-Sardinia from the House of Savoy in 1831. Anna Maria accepted her fate with admirable composure, referring to herself as her husband’s nurse. The marriage remained childless.

14. Hemophilia spread by Queen Victoria throughout European royalty

A photo of Queen Victoria
A photo of Queen Victoria

Queen Victoria’s gene can be traced to European royalties between the 19th and 20th Centuries. She married her first cousin, Prince Albert, and all her children were inbred. 

She had hemophilia, a severe blood-clotting problem that went to her that she passed on to her children and eventually to European royalty, making it known as the royal disease.

Hemophilia is caused when both parents have recessive genes. Queen Victoria had Hemophilia B, first appearing in her family in her 8th son, Prince Leopold, Duke of Albany. He suffered severe hemorrhages throughout his short life. 

13. Princess Victoria Melita’s royal never-ending headaches

A photo of Princess Victoria Melita
A photo of Princess Victoria Melita

Princess Victoria Melita was one of the European royalties – Queen Victoria’s granddaughter. Though she was far away from the royal disease, Hemophilia, she did suffer from the burden of headaches through her heredity and interconnected relations throughout Europe.

Queen Victoria made Princess Victoria marry the Grande Duke of Hesse ( her grandson ), resulting in continuous fights, a stillborn son, and their daughter dying at the early age of eight.

12. King George’s blue urine

A portrait of King George III
A portrait of King George III

King George III of England, one to lose the American Revolution, suffered from porphyria. This unique disease caused the sufferer hallucinations and turned the urine into a purplish-bluish color.

Recently, he is thought to have bipolar disorder caused by the inbreeding within the House of Hanover. He would talk continuously until he vomited foam and for such acts was infamous as the mad king. 

Eventually, his rich vocabulary quickly diminished, and he wrote long and confusing letters with sentences containing over 400 words.

He lost the American Revolution war due to his unstable state of mind. His treatments included the application of straitjackets and ice baths.

He was also treated with a medicine made from gentian for a skin condition known to turn urine purplish-blue and was diagnosed with porphyria.

The case of acute porphyria is followed by a degenerated nervous system, including symptoms such as hallucinations, delirium, insomnia, anxiety, and porphyria.

The king’s doctor might have worsened this condition by treating him with arsenic, basically poisoning him.

11. The royal temper tantrum of Maria the Mad, Queen of Portugal

A portrait of Maria I Queen of Portugal
A portrait of Maria I, Queen of Portugal

Maria I, Queen of Portugal, married her uncle, which made her son Prince Joao her cousin. She was religious, used to howl, make animal noises, and was taken as a manic for those reasons.

Maria went through a string of chain tragedies within three months. Her elder son and only daughter died of smallpox two months apart, followed by the death of her husband and newborn son.

After the death of her confessor, on whom she placed her entire trust and confidence due to stroke, she had raging temper tantrums as she screamed and wailed in her loss.

Later she was diagnosed as insane and underwent a series of horrifying treatments such as ice baths, blistering, and administration of laxatives. None of those treatments worked. Hence, the queen could not attend to her royal duties and had to designate a substitute.

10. Joanna of Castile, who slept beside her husband’s corpse

A portrait of Joanna of Castile
A portrait of Joanna of Castile

Joanna of Castile’s story is the most tragic of the many monarchs’ history. Joanna, a curious, intelligent, and moody woman, married Philip the Handsome. He was the son of the Roman Emperor Maximilian I, born from inbreeding.

She was fond of reading, leading to the mastery of the Castilian, Catalan, and Gallico-Portuguese languages and French and Latin. She excelled in dancing and playing clavichord; however, she was trained to be a good wife as she wasn’t expected to ascend to the throne.

While Joanna was utterly smitten with her husband, Philip loved his wife physically. He continued being disloyal to her, which made her jealous until she was depressed and eventually became a lunatic. 

Her marriage suffered other tragedies where her only son became fatally ill, died at eighteen, and gave birth to a stillborn.

She also had to face the loss of her sister and her son, which led her to take her oath as the heiress, taking the title of Princess of Asturias.

The same year, Joanna went through a complete mental breakdown, after which her husband would abandon her repeatedly as a punishment for her erratic and violent behaviors. 

She would cry herself to sleep and throw her body against the wall in misery. After the death of her husband, he lived her life in solitude as her son sent her back to captivity. Joanna wore black in mourning till her end.

9. Hemophilia that destroyed Alexei Romanov’s empire

A young photo of Alexei Romanov
A young photo of Alexei Romanov

Alexia inherited hemophilia from his mother, which typically affects males that she acquired through the line of her maternal grandmother, Queen Victoria of the United Kingdom. 

At birth, he was initially a healthy baby, but his navel bled for hours as his blood did not clot when they cut his umbilical cord. Emperor Nicholas II and Empress Alexandra, his parents, did not reveal this condition to the family of the Russian public.

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This secrecy caused rumors to rise, such as him suffering from tuberculosis and missing a layer of his skin.

His hemophilia was so severe that even minor injuries such as a nosebleed, bruise, or cut were potentially life-threatening. The recurrence of the condition and long-term recoveries interfered with Alexei’s childhood and education. 

In 1907, he fell and hurt his leg, which triggered an internal hemorrhage. Since the doctors could do nothing, Alexandra asked the Princess Anastasia of Montenegro to find Rasputin, who prayed over Alexei. 

Not long after Rasputin left, the swelling in Alexei’s leg went down. However, alcoholism, sexual promiscuity, and dabbling in the occult tainted Rasputin’s character, symbolizing everything wrong with the royal family.

As the disorder and discontent grew, the Russian Revolution began in 1917. It is still uncertain if Alexei’s illness was the reason for the Russian Revolution, the fall of the Romanovs, and the royal family’s execution. However, it surely did not help.

8. Depressed and anorexic Elizabeth, Empress of Austria

A portrait of Austrian Empress Elizabeth
A portrait of Austrian Empress Elizabeth

Elizabeth, like her parents, was married to one of her cousins, Franz
Josef. Her clan, the House of Wittelsbach, was infamous for inbreeding and troubling behaviors.

Elizabeth’s beauty was divine and is taken similar to Princess Diana’s. Sadly, as one of the most common products of inbreeding, she had a mental illness resulting in depression and anorexia. 

Her shy, melancholy, and timid nature were taken as a royal liability by her mother-in-law thought to be a royal liability. She ate very little and exercised obsessively for several hours a day as she developed an eating disorder and traveled a lot as it became a way of escape for her.

She suffered the most when her first child died in 1857, followed by her sister, mother, father, and only son’s loss. Her son died of suicide and has suffered from the same mental illness as his mother. 

She wandered in various places after his death, looking for solace, and was murdered in 1898 in Geneva, Switzerland, by one of the Italian anarchists.

7. King Ludwig II Overthrown by his Madness

A portrait of King Ludwig II
A portrait of King Ludwig II

King Ludwig II of the House of Wittelsbach was known for being mentally unstable and out of touch with reality. His mother noticed his interest in dressing up and vivid imagination as a child. 

He was nineteen when his father died as he ascended the Bavarian throne. He was not prepared for high office as he had no political experience. He continued the state policies of his father and retained his ministers.

He was famous for his youth and good looks, but his real interests lay in art, music, and architecture. He kept himself in the dream world he had created by becoming a personal patron of the composer Richard Wagner. 

He had all the comforts of the king without any responsibilities while the government of Bavaria struggled to run the state.

Ludwig did not get married, did not have any known mistresses, and was under immense pressure to produce an heir. Later, his diary, private letters, and personal documents revealed his homosexual desires, which he struggled to suppress to remain faithful to the teachings of the Catholic Church.

6. Cleopatra was Obese

A painting of Cleopatra
A painting of Cleopatra

Cleopatra, a robust ruler and mesmerizing seductress, was born to Ptolemy II Auletes and Cleopatra V.

Cleopatra’s father and mother were brother and sister, a custom of that dynasty for kings to marry their sisters to gain power. Cleopatra married her brother to keep her bloodline, continuing the inbreeding resulting in obesity.

Based on the archeologists’ research, Egyptians were overweight with their diet heavily containing bread and beer. Cleopatra’s look was not as depicted in movies and Roman propaganda. She had a round face with a hooked nose and a double chin.

Archeologists also claim that she had diabetes, balding in front and extended back hair. She wore black and red nail polish, sporting a goth look for someone past middle age.

5. Princess Nahienaena’s Incest

A painting of Princess Nahienaena
A painting of Princess Nahienaena

In the early 1830s, Christian commissionaires talked King Kamehameha III out of marrying his sister, Princess Nahienaena. They both got married to other people.

However, their love affair continued, and she gave birth to her brother’s child. They developed a romantic relationship when they were children, and their families approved of their relationship.

It was encouraged to marry once they attained maturity but came to a halt when Hawaii was in a state of cultural and political transition. Both their maternal grandparents were half-brothers married to half-sisters.

The king announced their marriage as an empowered king’s first act; still, the Christian missionaries were somehow able to persuade him not to do so. 

Princess Nahienaena gave birth to a child shortly after she married another man, and King Kamehameha declared that the child would be the next monarch claiming he was the father. 

Shortly after the birth, both the child and Princess Nahienaena died, which became a sobering and maturing moment for the king, making him committed to the business of modernizing his country.

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He was married to a low-level aristocrat, and neither of their sons survived to adulthood. Despite his tragedy, the king successfully transitioned his kingdom from an absolute to a constitutional monarchy. 

He was one of the few indigenous monarchs of the 19th century, maintaining the country’s traditions while adopting European modernity.

4. The many wives of King Rama V

A photo of King Rama V, leader of Siam - Thailand
A photo of King Rama V, leader of Siam – Thailand

King Rama V, one of the most outstanding leaders of Siam (Thailand), lived forever in a fictionalized story on British governess Anna Leonowens. 

Anna came to Siam as a teacher of King Mongkut’s children, among whom Rama V was the oldest son and the heir to their empire. 

He inherited the throne when he was fifteen-year-old in 1868, and being a well-educated young king, he planned on introducing reforms in the country, eventually modernizing the country.

Rama V had ninety-six wives and mistresses who gave him thirty-three sons and forty-four daughters. He married two of his half-sisters, who birthed his children as well. 

Bhumibol Adulyadej, the current King of Thailand and the wealthiest king globally, is the grandson of Rama V and one of his half-sisters.

King Rama V is known for the modernization of Siam, now known as Thailand, and for preventing its colonization by the British. He abolished slavery and built public hospitals and a railway. 

However, despite his achievements, to avoid being looked down upon by the Western leaders, he only introduced one of his wives- Queen Saovabha, to the public, knowing the shame polygamy and incest would bring him.

3. Nero drove to insanity by inbreeding

A white bust of Roman Emperor Nero
A white bust of Roman Emperor Nero

Dark traditions, inbreeding, and insanity can easily define Roman culture. Without mentioning one of the worst Roman emperors, Nero, the epitome of corruption, destruction, and wickedness, cannot be spoken about.

He attained power at the age of sixteen, and over the next fourteen years of his reign, he murdered two of his wives, his mother and his aunt, while marrying two men, creating incest with his mother, and sleeping with a Vestal Virgin

As if all of these actions weren’t enough, he set fire to Rome, played as the city burned, and blamed the Christians to deflect attention from himself.

This image of impulsive and crazy Nero has been preserved in films and TV series such as Quo Vadis and Nero Burning ROM’s computer software.

It was common for the Roman royals to inbreed to keep wealth and prestige within the family and reduce conflicts over who the heir to the throne should be.

Nero was born to Claudius and Agrippina. His parents were related ( uncle and niece), and the main reason behind marrying was to reinforce the son’s claim to the throne, which ended up as a bad sign for the city of Rome and the Romans.

His mental status was contributed by lead poisoning and mainly by inbreeding.

2. King Tut with a cleft palate and an elongated skull

A golden statue of King Tutankhamun
A golden statue of King Tutankhamun
Source: Wikimedia Common

Inbreeding goes far behind ancient Egypt as the Egyptian goddess Isis married Orisis, her biological brother. This was to continue the act of getting married within a biological relationship and keep the bloodline ongoing.

Many Egyptian pharaohs, deities, and Egyptians, including King Tutankhamen, followed this tradition. 

King Tut’s mummy scan showed that he was a frail and sick child with a club foot, cleft palate, very long skull, and suffered from malaria. The DNA study on his mummy revealed how those traits resulted from biological inbreeding.

King Tutankhamen probably spent most of his life in pain with a weakened spine, inflammation, and a complicated immune system before dying at nineteen. 

His statues depicted an oddly shaped head and a feminine body, including breasts. According to an author of the study from the Institute of Human Genetics at the University of Tubingen, Germany, his face had full and swollen lips and a slim nose. Still, people found no such evidence based on the new studies.

Tut’s tomb consisted of more than a hundred walking sticks because he had a clubbed left foot in which some of the bones in the toes were dying from a degenerative disease, making him walk ordinarily impossible.

His death was said to be caused by inbreeding rather than acute causes. 

His compromised immunity led him to death as his body was unable to cope with a severely broken necrosis of his right foot, along with his persistent malaria and other infections and health problems.

1. Caligula’s Bloodthirst

Roman Emperor Caligula
Roman Emperor Caligula
Source: Wikimedia Common

Caligula, the nickname given to famous Roman Emperor Gaius Julius Caesar Germanicus, the third son of Germanicus and Agrippina, was based on the miniature versions of military sandals while sitting with his parents on the German frontier. 

This led the soldiers to call him Caligula– little sandal. His mother and elder brothers were captured and died terribly for plotting the praetorian monitor Sejanus in his late teens. 

In an attempt to rid himself of Sejanus, believing he may be the potential successor, he too was arrested and put to death by the orders of Emperor Tiberius in 31 AD. 

The same year, he was invested as a priest, lived on the island of Capri in the emperor’s lavish residence, and was appointed joint heir with the son of Drusus, the younger Tiberius Gemellus.

Caligula was very tall with skinny legs, a thin neck, sunken eyes, temples, and a broad forehead. He had light hair with a bald top and a hairy body. 

He is thought to have attempted to kill Tiberius, who later recovered and returned from the dead. This terrified Caligula of the revenge he would have to face. However, Navevius Cordus Sertorious Macro, commander of the praetorians, smothered Tiberius with a cushion, suffocating him to death.


Consanguinity is no new concept in the ancient kingdoms, which was carried to keep the family bloodline pure and the power within their own families. It was prominent even in modern times from ancient Egypt among the European royalties.

This tradition, however, brought more destruction than prosperity by the time it was a generational system. Many royal disasters resulted from inbreeding, leading to a handful of diseases and deformities, including mental instability, depression, Madness, conditions such as hemophilia, and many other physical deformities. 

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