Following the death of the Home Alone actress Catherine O’Hara last week, searches for situs inversus, a rare congenital condition the actress was diagnosed with, have skyrocketed.
O’Hara passed away at her home in Los Angeles last Friday at the age of 71, following a brief illness, which has not been disclosed. Her cause of death has also not yet been released.
Situs inversus causes the major organs in the chest and abdomen to be in mirror-opposite positions from normal anatomy, and affects just 1 in 10,000 people.
In some cases, a person can live most of their life without realising they have it, as was the case for O’Hara.
In 2020, she revealed that she had only become aware of her condition after getting a tuberculosis test some 20 years prior, and medics saw her organs were inverse on a chest X-ray.
Internal imaging – using X-ray, ultrasounds and MRI and CT scans – is the only way to diagnose the condition, but it can cause a string of health conditions which could alert doctors that more investigations are warranted.
Approximately 3–5 per cent of people with situs inversus totalis have heart abnormalities.
If the heart is mirrored correctly – known medically as dextrocardia with normal structure – risk is low, but if there are abnormalities, it can lead to a plethora of problems.
Catherine O’Hara was diagnosed with situs inversus in 2000 when she had TB tests
These include holes in the heart, abnormal valves, problems with major blood vessels and heart rhythm issues.
Furthermore, around a quarter of people with situs inversus have a condition called primary ciliary dyskinesia (PCD) which causes chronic sinus infections, frequent chest infections, a persistent and mucus-heavy cough, ear infections and hearing problems.
Situs inversus, when present with sinus disease and lung problems is known as Kartagener’s syndrome, which has no cure and requires lifelong management.
Other complications caused by the condition include misdiagnosis of acute conditions due to the inverse location of organs – for instance the appendix – and failure to administer life-saving treatment such as CPR as the heart is in the ‘wrong’ place.
O’Hara reflected that she was the first patient with situs inversus her doctor had ever come across.
Speaking in the 2020 interview, she recalled he said: ‘You’re the first one I’ve met!’
‘I’m one of seven kids,’ O’Hara continued in the interview. ‘My parents were already gone, had left the world by that time. Never heard anything about this with anyone else. We’re driving home, and I think, “I wonder about my other siblings, if they know where their hearts are.”‘
‘When the doctor told us that my heart was on the right side and my organs were flipped, my husband immediately said, “No, her head’s on backwards,”‘ she recalled.
The above graphic shows normal anatomy (left) and the flipped anatomy (right) which is seen in people with situs inversus
Situs inversus totalis – the full term for complete anatomical reversal – has both intrigued and puzzled scientists for centuries.
Many believe the condition holds clues to understanding how our bodies differentiate right from left and the significance behind such a preference.
O’Hara admitted that she wanted to remain ignorant to her condition, adding: ‘I don’t even know the name because I don’t want to know the name. Something cardi-inversa and then dexter-cardia and something-inversa.
‘People are going to think I’m so ignorant not to know this, but I kind of don’t want to know because I didn’t know before that.’
Other celebrities who have the condition are Spanish singer-songwriter Enrique Iglesias and former teen idol Donny Osmond.
Below, The Daily Mail explains the condition and what it could mean for people’s health.
What is situs inversus?
In situs inversus, organs are in flipped or reverse positions.
Typically, the condition impacts the major organs, including the heart, lungs, stomach, liver and spleen.
Organs normally form in a left-right formation, but in situs inversus, they develop in a right-left formation, according to The Cleveland Clinic.
In people with situs inversus, the left atrium of the heart and the left lung are on the right side of the body. The liver would be on the left side instead of the right.
And the stomach and spleen are on the right side of the body instead of the left.
There are two types of situs inversus: dextrocardia with situs inversus, which is what O’Hara said she thinks she had, and levocardia with situs inversus.
The former occurs when the tip of the heart points toward the right side of the chest, instead of the left, and other organs are also flipped.
The latter occurs when the tip of the heart is pointing toward the left side as normal but other organs are flipped.
Join the debate
Were you aware of situs inversus?
O’Hara and Macaulay Culkin are pictured at Culkin’s star ceremony on the Hollywood Walk of Fame on December 1, 2023
O’Hara is pictured above arriving for the 24th Critics Choice Awards in January 2019
What causes situs inversus?
Situs inversus occurs when a person has a genetic mutation. More than 100 genes have been linked to organ-placement defects.
In order for someone to have the condition, they must have inherited a mutated gene from both of their parents.
Other risk factors for situs inversus include a family history of birth defects, maternal diabetes, use of cough suppressants during pregnancy, use of tobacco during pregnancy and low socioeconomic status.
Are there any complications from situs inversus?
Despite the organs being in the wrong position, they still function normally, so a person with situs inversus may not even know they have the condition and may not experience symptoms or any complications.
However, if the condition exists alongside others or defects, symptoms may occur.
People with situs inversus may experience other cardiac defects, including primary ciliary dyskinesia, which causes mucus to build up in the lungs.
This can lead to bronchitis and sinusitis.
While situs inversus may not interfere with health, it is important to be aware of the condition as it can lead to misdiagnosis or delay of care in some cases.
Can situs inversus be fixed?
The condition doesn’t cause symptoms that require medical treatment.
There is no cure for situs inversus and doctors will not recommend surgery to put the swapped organs back in their rightful places.
If there are any symptoms or complications arising from a co-occurring defect, doctors will treat those.
Fortunately, most people with situs inversus can live a healthy life and a typical lifespan.
