About Primary Ciliary Dyskinesia
The New York Center for Rare Diseases supports the mission and guidelines of the Genetic and Rare Diseases Information Center (GARD). The following information is provided by the NIH.
Summary
Primary ciliary dyskinesia (PCD) is an inherited disorder which affects the movement of tiny hair-like structures on body cells, known as cilia. Cilia are present on many types of cells, and particularly on those in the respiratory tract. In PCD, the cilia are abnormal, and don’t move correctly. People with this disorder cannot clear the mucous and fluid in their lungs and airways. This leads to frequent respiratory infections, and continuous nasal congestion and coughing. In addition, because cilia are involved in how the organs form and develop, many people with PCD may have abnormal placement of the organs in the body, known as situs abnormalities. For example, their heart may be on the right side of their chest instead of the left. Almost all males with PCD are infertile. PCD is caused by genetic changes in one of over 30 different genes involved in the formation of cilia, and is usually inherited in an autosomal recessive pattern in families. It is diagnosed based on the clinical symptoms. Other diagnostic tests may include ciliary analysis and genetic testing.
Causes
What Causes This Disease?
Genetic Mutations: Primary ciliary dyskinesia is caused by genetic mutations, also known as pathogenic variants. Genetic mutations can be hereditary, when parents pass them down to their children, or they may occur randomly when cells are dividing. Genetic mutations may also result from contracted viruses, environmental factors, such as UV radiation from sunlight exposure, or a combination of any of these.
If you suspect you may have this disease, you may want to start collecting your family health history. Information such as other family members who have had similar symptoms, when their/your symptoms first appeared, or exposures to any potential disease-causing environmental factors should be discussed with your medical team.
Known Genetic Mutations: Primary ciliary dyskinesia is caused by genetic mutations in the following known gene(s):
RSPH9, DNAI1, SPEF2, CFAP300, LRRC6, LRRC56, NEK10, RSPH1, DNAH9, CCDC114, RSPH4A, CCDC40, FOXJ1, HYDIN, DNAAF1, DNAI2, C21orf59, ZMYND10, TTC12, PIH1D3, ARMC4, DNAJB13, RSPH3, RPGR, DRC1, DNAAF2, OFD1, DNAH5, TTC25, CFAP221, CCDC103, DYX1C1, SPAG1, GAS8, CCDC39, STK36, MCIDAS, CCDC151, CCDC65, DNAAF3, DNAL1, DNAH1, HEATR2, NME8, CCNO, DNAH11, GAS2L2
Given these known genetic mutation(s), you may want to ask your health care team if genetic testing is right for you. Genetic tests are laboratory tests that use samples of blood, saliva, or other tissues to help identify changes in genes, chromosomes, or proteins. Genetic testing can help confirm or rule out a suspected genetic disease, or can provide other useful information to your health care team.
Can This Disease Be Passed Down From Parent to Child?
Yes. It is possible for a biological parent to pass down genetic mutations that cause or increase the chances of getting this disease to their child. This is known as inheritance. Knowing whether other family members have previously had this disease, also known as family health history, can be very important information for your medical team.
There are multiple ways, or patterns, a disease can be inherited depending on the gene(s) involved. Based on GARD’s current data, this disease can be inherited in the following pattern(s):
Autosomal Dominant: Autosomal means the gene involved is located on one of the numbered chromosomes. Dominant means that a child only needs to inherit one copy of the mutated gene, from either biological parent, to be affected by the disease.
People affected by an autosomal dominant disease have a 50% chance of passing on the mutated gene to their biological child.
Autosomal Recessive: Autosomal means the gene involved is located on one of the numbered chromosomes. Recessive means that a child must inherit two copies of the mutated gene, one from each biological parent, to be affected by the disease. A carrier is a person who only has one copy of the genetic mutation. A carrier usually doesn’t show any symptoms of the disease.
If both biological parents are carriers, there is a 25% chance their child inherits both copies of the mutated gene and is affected by the disease. Additionally, there is a 50% chance their child inherits only one copy of the mutated gene and is a carrier.
X-Linked: X-linked inheritance means the genetic mutation is located on the X chromosome, one of the sex chromosomes. The male sex chromosome pair consists of one X and one Y chromosome (XY). The female sex chromosome pair consists of two X chromosomes (XX). Because males have just one X chromosome, it takes only one copy of the mutated gene to cause the disease. Females that have one copy of the mutated gene may have symptoms similar to those experienced by affected males, but usually have less severe symptoms, or no symptoms at all.
Female parents with one X-linked mutated gene have a 50% chance of passing on the mutation to each of their biological children. Male parents with an X-linked mutated gene will pass on the mutation to all their female children but cannot pass the mutation on to their male children.