What is situs inversus? The rare condition Catherine O’Hara suffered as she dies at age 71
Catherine O’Hara, the beloved actor known for Schitt’s Creek, Home Alone, and Best in Show, has died at the age of 71.
O’Hara passed away at her home in Los Angeles on Friday ‘following a brief illness,’ according to a statement from her agency CAA.
The actor was last seen publicly in September 2025 at the Emmy Awards where she appeared frail and thinner than usual.
The cause of death has not been released and it it not known what illness O’Hara had been experiencing.
She had previously been diagnosed with situs inversus, a rare congenital condition where major organs in the chest and abdomen are in mirror opposite positions from normal anatomy.
The Cleveland Clinic reports that one in every 10,000 people have situs inversus and the condition is more common in males.
O’Hara rarely spoke about her condition but said in an interview that she had to get a tuberculosis test when her son was in nursey school. While doing preliminary tests, she got a chest x-ray, which revealed her sinus inversus.
She said: ‘I’m a freak! I love Western medicine, I just don’t want to be a part of it.’
Catherine O’Hara arrives at the Emmy Awards in Los Angeles, California, on September 14, 2025
The above graphic shows normal anatomy (left, situs solitus) and the flipped anatomy (right) that is observed in people with situs inversus
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.’
Below, 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.
O’Hara and Macaulay Culkin at Culkin’s star ceremony on the Hollywood Walk of Fame on December 1, 2023
O’Hara is seen 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 other conditions 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 it may not interfere with health, it is important to be aware of the condition as it can lead to misdiagnosis or delay of care if 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.
