This episode is sponsored by Toodaloo, a  healthy and flavorful cosmic trail mix.

To try Toodaloo, check out toodaloo.com/SCISHOW and use the code SCISHOW to  get $5 off your first order! [♪ INTRO] Some people are constantly coughing up mucus, and it’s not always because they  have a perpetual cold or allergies. Sometimes, that symptom is caused  by a rare genetic disease that puts your organs on the opposite side  of your body from everyone else’s.

Your organs can be flipped! Like, you’d put your left hand over your heart because it’s on the right side of your body. And this doesn’t always cause as  many problems as you might think.

For some people, this condition does  lead to life-threatening complications, but others can have long, fulfilling lives and not even know that their organs are flipped. And it all comes down to how  your cilia work, or don’t work. Cilia are kind of like  millipede legs for your cells.

They stick out like hairs  from the surface of a cell and rotate to help that cell  move around in your body. And cells need to move around  because of the way fetuses develop. During development, cells are rapidly  growing and dividing to form a human, and most of those cells eventually  specialize to do certain jobs.

Like, some cells in your intestines  help you get nutrients from your food, and other cells in your heart  help you circulate blood. But those cells start specializing  before they really have a place to go. For instance, your heart is one  of the first organs you made, and you started forming heart cells  before you had a chest to put them in.

And many organs start developing before or as they travel to where they’ll sit  for the rest of someone’s life. So besides moving cells around generally, cilia are also necessary to get  those organs where they're going. Sometimes cilia move the cells that they’re on, and sometimes they move cells  through a different mechanism.

By beating the fluid around  them, they generate a current that acts like the lazy  river of human development. Either way, when cilia aren’t working properly, cells and organs can end up in uncommon locations. And before you know it, you’ve grown  a body with a bunch of flipped organs, including your heart, liver, and spleen.

They’re still whole organs, and they  generally do what you need them to, but they aren’t where you might expect them to be. This is what happens in Kartagener syndrome. It’s a rare genetic disease  that affects anywhere from 1 in 12,000 to 1 in 30,000 people.

It’s one kind of Primary Ciliary  Dyskinesia, or PCD, which is a category of conditions where someone’s cilia don’t  move the way other people’s move. And it develops when someone receives otherwise harmless copies of one or more  genes from both of their parents. At this point, researchers don’t know exactly which genes are at the root of all  this, but they have a few ideas.

For example, PCD has been linked to at least three genes that lead to  loss of dynein arms in cilia. Dynein arms are the part of the cell that  give energy to cilia so that cells can move. So if a cell is missing dynein arms, it’s  unlikely that it could travel around.

There’s more nuance to it than that, but in general dynein arms seem pretty  important to get your cilia going. And ciliary dysfunction has been reported in several other structures related to dynein arms. And there are a bunch of proteins  involved in their assembly that researchers are studying to get  a better understanding of PCD.

Overall, when it comes to  Kartagener syndrome specifically, most cases involve mutations in the outer  dynein arms, but not all of them do. That means PCD and Kartagener syndrome  manifest in a variety of symptoms that may look different in individual cases. And how long it takes before you get a  diagnosis can affect health outcomes.

But generally, people living  with Kartagener syndrome have more than just flipped organs. That’s a big part of it, but they  might also have chronic sinus problems, cough up mucus, and experience infertility. . . . And that’s because cilia don’t  /just/ help organs get organized.

They have plenty of other jobs  throughout someone’s life, including helping sperm move, eggs  implant, and mucus clear from the lungs. In some cases, this can lead to Kartagener  syndrome being life-threatening, because if mucus doesn’t get cleared out  of airways effectively and blocks airflow. So, when your cilia don’t work  the way other people’s do, it can have big impacts on  more than just organ location.

Really, these little cilia do so much for us! And when they don’t, it can be a big deal. PCD has been compared to  Gastroesophageal Reflux Disease, which is a digestive disorder.

And when things aren’t going  as you might hope they would with your digestive system,  it can throw you for a loop. So to help maintain gut health, Toodaloo  has Hot to Trot spicy citrus trail mix. It’s full of powerful ingredients  like ginger powder, turmeric extract, and lemon peel to make your mouth  tingle and get your gut going.

They also have Slow Your Roll maple trail  mix, which tastes just like pancakes. Toodaloo’s trail mix is full of herbs to support your body’s natural stress  relief and energy production. And they do it all in a plant-based,  carbon conscious, and plastic neutral way.

So you can be good to your body and  good to the world at the same time. To try Toodaloo, check out  toodaloo.com/SCISHOW and use the code SCISHOW to get $5 OFF your first order. And they’ve got an OMG Guarantee, so  if you don’t agree that Toodaloo is the most delicious trail mix you’ve ever  eaten, they’ll give you a full refund.

Thanks to Toodaloo for supporting this  SciShow video and thank you for watching. [♪ OUTRO]