|Frequently Asked Questions|
The information contained on this site does not constitute medical advice and the PCDF cannot respond to questions from patients about individual therapies. The goal of presenting these FAQs and information of a possible treatment picture is not to suggest that this what every PCD patient should be doing, but to make you aware of options for treatment which may or may not be appropriate for you at this time. PCD is rare disorder that is still being investigated. No one has all the answers about the best or most effective way to treat PCD right now. These FAQs are an effort to address some of the most common questions about PCD that affect the patient population as a whole with the most up-to-date information currently available. No single treatment plan or therapy is right for everyone with PCD and it is important to consult your physician.
PCD stands for primary ciliary dyskinesia, an inherited disorder of motile (moving) cilia. PCD is also sometimes referred to as Kartagener syndrome (PCD with situs inversus) or immotile cilia syndrome.
Effective activity of motile cilia is required to keep the lungs, sinuses and ears free of organisms and debris that can cause infection and disease. Motile cilia also are important in helping determine organ placement in the developing embryo and in moving the cells of reproduction into place (egg cells through the ciliated fallopian tube in females and sperm via sperm tails that closely resemble cilia in the male). Motile cilia are also found in the ventricles of the brain.
A person with PCD experiences chronic, recurrent infections in the lungsears and sinuses due to the loss of ciliary activity in those areas. Faulty determination of organ placement (aka ‘situs’) may result in reversed organs or in other organ placement/development abnormalities. Reduced spermmotility means that most males with PCD are infertile (not sterile—the sperm are still viable, they just can’t get where they need to be) and women with PCD may experience subfertility or increased risk for miscarriage or ectopic pregnancy. Some women with PCD are able to conceive with no problems. In very rare instances, PCD may be associated with hydrocephalus, a condition in which excess fluid in the ventricles of the brain causes them to be enlarged.
For more information, read this paper published by the University of North Carolina, Chapel Hill PCD research team: http://www.ncbi.nlm.nih.gov/books/NBK1122/
PCD is a genetic disorder, meaning it is inherited from one’s parents and cannot be acquired from the environment. PCD is most often passed in what is called an ‘autosomal recessive’ pattern of inheritance, in which the disease is only expressed when a child inherits two copies of a mutated gene—one from each parent. The parents are considered ‘carriers’ because they ‘carry’ the mutation, but are not sick themselves because they only have one copy of the mutated gene. When two carriers produce children, however, they have a 1 in 4 (25%) chance of having a child who will inherit both of their mutations, which will result in the disease being expressed.
One common misconception with PCD is that since it is inherited, it should be seen in other family members. Recessive diseases simply don’t appear in that way. Carrier status can be unknowingly passed in a family for decades, possibly even centuries, before a carrier meets another carrier by random chance and they produce an affected child. Because there is a 1 in 4 chance (with each pregnancy, not with the total number of children produced) of passing a recessive disease, it is not uncommon to see family groups with multiple affected siblings. It is not common, however, for PCD to pass fromparent to child to aunt to cousin, etc. This form of inheritance suggests thatsomething other than a recessive trait is at work.
Because we don’t know everything about PCD genetics at this point, suspicion of PCD requires diligent workup from PCD experts to make sure that the diagnosis has not been made in error.
For more information:
Diagnosis by clinical symptoms alone is not a valid way to confirm PCD because the symptoms of PCD overlap with a number of other disorders. Sometimes it is not possible to confirm the diagnosis of PCD using currently available methods so PCD is simply assumed to be the underlying disorder.This can be useful for directing treatment, but its important to note that a clinical diagnosis alone does not constitute a confirmed diagnosis. Insurance companies often now ask for proof of the diagnosis either by biopsy or genetic testing. Clinical diagnosis alone may also make it difficult to participate in research projects, since accurate data collection requires that the diagnosis be verified.
Getting a confirmed diagnosis of PCD is fraught with all sorts of challenges right now, resulting in a huge problem with misdiagnosis—either people with PCD not being diagnosed or people with some other underlying condition being mistaken for PCD. This is frustrating for families, researchers and treating physicians alike and underscores the need for comprehensive genetic testing rather than biopsy as the gold standard.
There are currently only two officially recognized ways to make the diagnosis of PCD: A biopsy that evaluates the ultrastructure (internal components) of a cilium and genetic testing. Ultimately, genetic testing will be the best, most reliable method for making the diagnosis, but currently available genetic testing does not pick up all known mutations for PCD. For this reason ciliary biopsy performed at a center trained to collect, process and analyze cilia for PCD is still the ‘gold standard’ for diagnosis.
Nasal Nitric Oxide
Nasal nitric oxide (NO—‘nitric’ not ‘nitrous’ oxide) measurement is a good screening test for children over the age of five, but it is not diagnostic. People with PCD have unusually low levels of nasal NO for as yet unknown reasons. However, other conditions can also result in low nasal NO, including cystic fibrosis and some forms of severe sinusitis. For this reason, nasal NO tends to be better at ruling PCD out, then at ruling it in. If a person over the age of five has a normal nasal NO level, it is less likely that PCD is the cause of their symptoms.Back to top
Our bodies need oxygen to survive. The best way to get oxygen from the outside atmosphere is to breathe in large amounts of air through the nose and mouth into the lungs where it is absorbed into the blood stream and pumped by the heart throughout the body. Unfortunately, outside air also contains things we don’t want in our lungs, like pollutants, germs and dust.
These unwanted particles are breathed in, as well. Sometimes these particles can be dangerous or cause disease, so the body has developed an elegant system for removing unwanted particles called mucociliary clearance. Mucociliary clearance consists of cilia in the right quantity and of the right length beating vigorously in a set pattern in a fluid layer in the airways. This fluid layer is topped by mucus of a very specific stickiness and amount that traps debris and pathogens. The ciliary activity underneath this sticky mucus moves the mucus toward the mouth where it can be coughed out or swallowed. Together, properly functioning cilia, mucus of the right stickiness and quantity and a vigorous cough provide an important line of defense for the lungs.
When any of these three components is impaired, the lungs are not able to effectively remove inhaled particles. Sensing the presence of unwanted elements, the lungs step up production of mucus to flush them out. If the mucus cannot be moved because it is too sticky (as in cystic fibrosis), the cilia aren’t beating (as in PCD) or cough is impaired (as in a number of neuromuscular disorders), a vicious cycle of mucus over-production, inflammation and infection occurs. In time, repeated and chronic infections actually damage the airways, a condition known as bronchiectasis, and the cycle continues to get more severe.
In PCD and CF, the mucociliary clearance system is profoundly damaged from birth. In PCD, cough is generally spared, which may explain why lung damage in PCD usually progresses more slowly than in CF. In CF, extremely sticky mucus makes cough ineffective, as well, so all components of primary lung defense are impaired. In both disorders, bronchiectasis is nearly universal and as it progresses, more serious infections with difficult to treat bugs become common.
There is no cure for PCD, but aggressive treatment to slow the progression of bronchiectasis in the lungs and to address other PCD-related problems with ears, sinuses and other related issues can do much to promote a relatively healthy life. Research is the key to better treatments and ultimately a cure. Supporting research efforts in PCD is the most important thing you can do to improve the quality of life for those with PCD.
Because we have no formal way of collecting this data right now (like a registry, which we are working on through our Path to Clinical Trials program), we cannot say for sure. Most papers say life expectancy in PCD is ‘near normal,’ but that is based on experience with a limited number of patients. The PCDF’s informal data collection indicates that there is a wide range of life expectancy in the PCD population. In addition to the focus on age at death, it is equally important for us to assess age at disability from lung disease because that certainly interferes with ‘normal’ life.
PCD is a rare disorder and like any rare disorder, the best care comes from centers familiar with the disease. We currently have seven expert centers in the US and two in Canada, which can be found here:
If it is not possible to get to one of the PCD expert sites, the next best thing is to be seen at a cystic fibrosis clinic where doctors are familiar with mucociliary clearance disorders, bronchiectasis and most importantly, the need to treat preventatively, rather than just as symptoms arise.
If none of these options work for you please contact the PCD Foundation and we will try to help you find someone in your area.
The genetic mutations that cause PCD are found in every cell of the body and the only ‘cure’ for PCD is repairing these mutations. A lung transplant means your lungs will no longer be affected with PCD, but it does not cure PCD and you will still have ear and sinus problems related to the disorder. Additionally, many people are unaware that the cilia in transplanted lungs do not work for many months after transplant, so while the transplanted lungs don’t have PCD they do have ciliary impairment until function is restored. Lung transplant is a major procedure involving life-altering changes. It is a last resort for treating PCD lung disease when all other options have failed, rather than an alternative treatment option.
Gene therapy is not currently available for treating PCD. There are promising advances in potential treatments related to genetic mutations being investigated in the lab right now, but it will be some time before true gene therapy is an option in PCD.
To understand clinical trials (clinical research), it is important to understand what research is. ‘Research’ is a broad term that encompasses many different aspects of scientific discovery. In medicine, research is a systematic way to evaluate effects that are observed under controlled conditions. The goal of this controlled observation and analysis is to reach validated (credible) conclusions about the nature of a disorder, the safety or effectiveness of a particular treatment, the best course of treatment, or to collect data that will direct future research efforts.
The notion of ‘validation’, or establishing that the conclusions reached can be supported by data and evidence, is the most crucial aspect of research. It is not enough that research be done. It must be done using standards agreed up on by the scientific community in order to achieve broad acceptance. Without the acceptance of the scientific community, it is very unlikely that a treatment or prevention would become standard of care or that insurance providers would cover it.
Generally, achieving validity requires the involvement of large numbers of clearly identified individuals.
These requirements are particularly difficult for rare and difficult-to-diagnose disorders like PCD to meet. Nevertheless, we are making progress in meeting these basic requirements and are finally at the point where we can anticipate participation in clinical trials.
In broad terms, clinical trials are those done on human subjects with the goal of understanding the natural history of a disease, validating diagnostic tools, or evaluating a treatment or intervention. Basic science research generally refers to studies done attempt to answer more fundamental, but equally important, questions that may be used as the foundation for further research. For affected individuals, the importance of clinical research is obvious, but it would be a mistake to discount the importance of basic science research.
In PCD for example, the genetic mutations that cause the human disease were discovered in large part by basic science research done on a single celled organism called Chlamydomonas. These discoveries were then translated (“translational research” is another term you may have heard) for use in human genetic testing. Ideally, both targeted basic science research and clinical research are employed in understanding a disease.
We would all be skeptical if a friend with no medical background offered to do brain surgery on us, right? The reason for this is that we understand that there is a significant foundation of knowledge and skill that must be achieved before attempting anything as complex as brain surgery. Learning about cells and frequently biology allows a student to move on to basic anatomy and physiology, which in turn allows more in-depth study into brain anatomy and physiology, and so forth.
We would not have much faith in a practitioner who skipped any of these crucial steps. The same is true in research. For the results to be valid, a solid foundation of fundamental knowledge needs to be built first. In PCD, we are well into the process of building that foundation through NIH-sponsored GDMCC studies that clarify the natural history and progression of disease in PCD.
We must have evidence of what can be expected to happen in PCD for trials of therapies or preventive measures to have any meaning. Building this foundation is expensive and time-consuming, but it is essential. The support of the PCD community in facilitating these trials is critical to advancing future research efforts.
There are no PCD-specific programs to help pay for drugs and care and, unfortunately, many of the drug manufacturer programs are available only to people with a diagnosis of CF. However, there are assistance programs available in many states for children with chronic illnesses. Many of these programs have more generous income guidelines than traditional Medicaid programs and provide help with medical and drug costs. Children and adults with PCD might also be eligible for Medicare or SSD/SSI depending on income and current health status. Social workers affiliated with your clinic or hospital should be to help you determine which plan might be right for you.
There is a great deal of work to do in PCD research, education andawareness and every member of the PCD community has a valuable contribution to make. We need a strong patient advocacy group to lead the charge and dedicated volunteers in the community to spread the message. There are many ways you can help.
Here are some ideas: