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DICER1 syndrome is an inherited disorder that increases the risk of a variety of cancerous and noncancerous tumors, most commonly certain types of tumors that occur in the lungs, kidneys, ovaries, and thyroid (a butterfly-shaped gland in the lower neck). Affected individuals can develop one or more types of tumors; even members of the same family can have different types. However, the risk of tumor formation in individuals with DICER1 syndrome is only moderately increased compared with tumor risk in the general population; most individuals with genetic changes associated with this condition never develop tumors.
People with DICER1 syndrome most commonly develop pleuropulmonary blastoma, which is characterized by tumors that grow in lung tissue or in the outer covering of the lungs (the pleura). These tumors occur in infants and young children. Pleuropulmonary blastoma is classified into three types based on characteristics of the tumors: in type I, the growths are composed of air-filled pockets called cysts; in type II, the growths contain both cysts and solid tumors (or nodules); and in type III, the growths are composed solely of nodules. Types II and III are considered cancerous and can spread (metastasize), often to the brain, liver, or bones. Individuals with pleuropulmonary blastoma may develop an abnormal accumulation of air in the chest cavity that can lead to the collapse of a lung (pneumothorax).
Cystic nephroma, which involves multiple noncancerous (benign) fluid-filled cysts in the kidneys, can also occur in people with DICER1 syndrome. When associated with DICER1 syndrome, the cysts develop early in childhood and usually do not cause any health problems.
DICER1 syndrome is also associated with tumors in the ovaries known as Sertoli-Leydig tumors, which typically develop in affected women in their teens or twenties. Some Sertoli-Leydig cell tumors release the male sex hormone testosterone; in these cases, affected women may develop facial hair, a deep voice, and other male characteristics. Sertoli-Leydig tumors usually do not metastasize.
People with DICER1 syndrome are also at risk of multinodular goiter, which is enlargement of the thyroid gland caused by the growth of multiple fluid-filled or solid tumors. The tumors are generally slow-growing and benign. Despite the growths, the thyroid's function is normal. Multinodular goiter usually begins in adulthood.
DICER1 syndrome is a rare condition; its prevalence is unknown.
DICER1 syndrome is caused by mutations in the DICER1 gene. This gene provides instructions for making a protein that is involved in the production of molecules called microRNA (miRNA). MicroRNA is a type of RNA, a chemical cousin of DNA, that attaches to a protein's blueprint (a molecule called messenger RNA) and blocks the production of proteins from it. Through this role in regulating the activity (expression) of genes, the Dicer protein is involved in many processes, including cell growth and division (proliferation) and the maturation of cells to take on specialized functions (differentiation).
Most of the gene mutations involved in DICER1 syndrome lead to an abnormally short Dicer protein that is likely unable to produce miRNA. Without regulation by miRNA, genes are expressed abnormally, which could cause cells to grow and divide uncontrollably and lead to tumor formation.
Changes in this gene are associated with DICER1 syndrome.
DICER1 syndrome is inherited in an autosomal dominant pattern, which means one copy of the altered gene is sufficient to cause the disorder. It is important to note that people inherit an increased risk of tumors; most people who have mutations in the DICER1 gene do not develop abnormal growths.
These resources address the diagnosis or management of DICER1 syndrome and may include treatment providers.
You might also find information on the diagnosis or management of DICER1 syndrome in Educational resources (http://www.ghr.nlm.nih.gov/condition/dicer1-syndrome/show/Educational+resources) and Patient support (http://www.ghr.nlm.nih.gov/condition/dicer1-syndrome/show/Patient+support).
General information about the diagnosis (http://ghr.nlm.nih.gov/handbook/consult/diagnosis) and management (http://ghr.nlm.nih.gov/handbook/consult/treatment) of genetic conditions is available in the Handbook. Read more about genetic testing (http://ghr.nlm.nih.gov/handbook/testing), particularly the difference between clinical tests and research tests (http://ghr.nlm.nih.gov/handbook/testing/researchtesting).
To locate a healthcare provider, see How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.
You may find the following resources about DICER1 syndrome helpful. These materials are written for the general public.
You may also be interested in these resources, which are designed for healthcare professionals and researchers.
For more information about naming genetic conditions, see the Genetics Home Reference Condition Naming Guidelines (http://ghr.nlm.nih.gov/ConditionNameGuide) and How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.
Ask the Genetic and Rare Diseases Information Center (http://rarediseases.info.nih.gov/gard).
autosomal ; autosomal dominant ; benign ; cancer ; cell ; cysts ; differentiation ; DNA ; dysplasia ; expressed ; familial ; gene ; goiter ; hormone ; inherit ; inherited ; messenger RNA ; metastasize ; molecule ; nephroma ; pleura ; pneumothorax ; population ; predisposition ; prevalence ; proliferation ; protein ; RNA ; sex hormone ; susceptibility ; syndrome ; testosterone ; thyroid ; tissue ; tumor
You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://www.ghr.nlm.nih.gov/glossary).
The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.