Gene find for rare respiratory disease, primary ciliary dyskinesia (PCD)

Scientists have uncovered a gene linked to a rare disease that causes respiratory problems similar to cystic fibrosis.

Primary ciliary dyskinesia (PCD) is an inherited condition affecting cilia, the hair-like projections from some cells, such as those that line the respiratory tract. Cilia form part of the body's defence mechanism against microbes entering the lungs, so people with faulty cilia are prone to serious respiratory infections.

The genetic cause of PCD is unknown in around 40% of cases, even though around 30 genes have been identified for this condition.

'Our research means that we can now give more patients a genetic diagnosis', said Dr Hannah Mitchison of University College London, who led the study and will be presenting the results at the annual conference of the British Society for Genetic Medicine.

'Having a better understanding of the genetics behind PCD means we can begin to identify which mutations cause the most severe problems in patients, and tailor treatment to them.'

PCD affects 1 in every 20,000 people and causes chronic respiratory problems similar to those seen in cystic fibrosis, as well as causing hydrocephalus and infertility. In severe cases, patients may need to receive experimental heart and lung transplants.

The researchers worked with a family where two children had PCD, the genetic cause of which was unknown. After looking at the genes of the affected children and comparing them with the DNA of their healthy family members, they found that a mutation in the CCDC151 gene was to blame.

This type of mutation is a so-called nonsense mutation, which has the potential to be corrected by a novel kind of genetic therapy called read-through therapy. 'Read-through therapy is currently being tested in people with cystic fibrosis and we think it's promising for this type of mutation in PCD patients', said Dr Mitchison.

The researchers hope that their work will improve our understanding of the disease, and plan to investigate how different gene variants affect symptoms and how the disease progresses.

'We're only just beginning to understand the correlations between the type of gene variant a person has, and the severity of their condition. By looking at the genetics behind PCD, we hope to be able to match up the genetic cause with disease progression and predict how the symptoms could affect each patient', she said.

'Having a better understanding of the genes that cause PCD will allow us to think about genetically-targeted therapies going forward', added Dr Mitchison.