A rare disease called Kartagener syndrome causes interesting effects for the one in 16,000 people born with it in the United States. It’s an autosomal recessive genetic disorder, meaning the gene for it must be inherited from both parents for the condition to be present, and even if both parents are carriers, there’s only a one in four chance that a child of theirs will have the condition. It is primarily is disease of the respiratory system, though there are also effects on the reproductive organs—the fallopian tubes in women and sperm in men, affecting the fertility of people with the condition.
An odd feature of Kartagener is what is known as situs inversus. The layout of organs in the human body is a fairly consistent thing; where the heart is, the lungs, all the other organs. Sometimes, however, the organs are reversed, with the heart on the right side and the layout of the organs mirror-reversed. By itself, situs inversus has no effect on health, but about a quarter of people with it have Kartagener disease. One of the effects of the disease is that, through the same mechanism by which it affects the respiratory and reproductive systems, it causes problems with the placement of the organs in prenatal development, leading to the reversal.
Other effects of Kartagener include trouble getting mucous out of the lungs, chronic recurring sinus inflammation, frequent bouts of bronchitis, recurrent pneumonia, and frequent inner ear infections. Progressive lung disease, which gets more or less steadily worse as time goes on if left unchecked, is also common, generally starting in childhood. Hearing loss or a poor sense of smell is also common.
There is no cure, but infections can be treated as they occur. The condition is too rare to be well-studied or commonly planned for, but the usual practice, as with anyone known to be especially prone to breathing difficulties and infections is to keep a close eye on respiratory health in order to quickly notice and deal with anything that comes up. In extreme cases, a lung transplant may be necessary, though the odd anatomical effects can make this complicated. Kartagener patients can generally expect to live a normal lifespan.