Primary Ciliary Dyskinesia (PCD)
Description
Primary Ciliary Dyskinesia (PCD) is a rare genetic disorder that affects the cilia, tiny hair-like structures found on the surface of cells. These cilia play crucial roles in various bodily functions, including clearing mucus from the lungs, transporting eggs in the fallopian tubes, and regulating fluid flow in the brain. When cilia are defective due to PCD, it can lead to a range of health issues.
Genes Involved
Genes Involved:
PCD is caused by mutations in genes responsible for building and functioning cilia. Over 40 genes have been linked to PCD, including:
- DNAI1
- DNAH5
- DNAH11
- RSPH1
- CCDC39
- CCDC40
- CCDC151
- DNALI1
- DRC1
- TTC21B
- TMEM216
- WDR34
- LRRC50
- RSPH9
- RSPH14
- TTC26
Recognizing the Signs and Symptoms
Recognizing the Signs and Symptoms:
- Chronic Respiratory Issues: Frequent respiratory infections (bronchitis, pneumonia), persistent cough, difficulty clearing mucus, and sinus problems are common.
- Male Infertility: Defective cilia in the sperm can impair motility and fertilization.
- Situs Inversus: A rare condition where the organs are mirrored on the opposite side of the body (e.g., heart on the right side).
- Chronic Ear Infections (Otitis Media): Cilia in the middle ear help drain fluid, so PCD can lead to recurring ear infections.
- Reduced Fertility in Females: Cilia in the fallopian tubes help transport eggs, so PCD can affect fertility.
- Hydrocephalus: Rarely, PCD can cause fluid buildup in the brain (hydrocephalus) due to defective cilia in the cerebrospinal fluid system.
Causes
Causes:
PCD is an inherited genetic disorder, meaning it‘s passed down from parents to their children. In most cases, the mutations occur spontaneously in the sperm or egg cell, but they can also be inherited from a parent carrying the gene mutation.
Inheritance/recurrence risk
Inheritance or Recurrence Risk:
- Autosomal Recessive Inheritance: PCD is usually inherited in an autosomal recessive pattern. This means both parents must carry the gene mutation for their child to have PCD.
- Recurrence Risk: If both parents carry the mutation, there‘s a 25% chance with each pregnancy that the child will inherit PCD.
- De Novo Mutations: In some cases, the mutation can occur spontaneously during the formation of the sperm or egg cell, even if neither parent carries the mutation. This is called a ‘de novo‘ mutation.
