The PPB Genetic Research Study has been underway since 2005. Many patients and families have participated.
Where do things stand? What have we learned?
In April, 2009, Dr. Ashley Hill released the initial results of this research. We also sent an informative letter to all families and patients who had participated.
The results were as follows: in eleven families in which there were PPB and certain other related medical conditions, we found an alteration (mutation) in the DNA sequence of a gene called DICER1. We believe this mutation may be associated with a risk for developing PPB.
The results were based on a particular group of patients and families: eleven families in which there were cases of PPB and lung cysts, cystic nephroma of the kidney and/or a childhood cancer called rhabdomyosarcoma. These families were selected for the earliest detailed evaluation because they were large families in which the disease pattern was especially characteristic and because we had excellent participation from many individuals.
A mutation is an error in the information code of a gene. Genes are the instructions for making proteins. The DICER1 gene and the dicer protein are involved with important processes controlling how cells function. In a few studies in animals, if the dicer gene is impaired, lungs may not develop properly. So it is possible that a human DICER1 gene mutation could contribute to PPB occurring in children.
Although we believe this is an important development, our research is still in early stages. There is much more to be learned. For example, we need to study many more patients and many more families to determine whether this mutation is present most PPB patients or perhaps only in large families. We know that some individuals have the DICER1 mutation but have not had any medical problems. We need to learn what factors other than a DICER1 mutation might also contribute to causing PPB.
This DICER1 mutation finding is the first step toward a better understanding of how and why some PPBs occur. We have many DNA samples still to be analyzed so that we can learn how broadly this DNA abnormality (mutation) affects children with PPB.
We request the continued participation of families in which there is PPB. We need to learn if any new medical circumstances occur in individuals who have already participated. Contact us if you want more information on the results announced in April 2009.
New Partipants Needed
In the first years of our work, we focused on families in which there were PPB and other related conditions. Based on our early findings, we must extend this work. We especially need to learn whether single, isolated, so-called “sporadic”, cases of PPB are associated with abnormalities of DICER1. Thus, we respectfully ask for the participation of every child who has PPB and of their parents.