What is retinoblastoma?
The following text is taken from the Genetics Home Reference (update pending):
Retinoblastoma is a rare type of eye cancer that usually develops in early childhood, typically before the age of 5. This form of cancer develops in the retina, which is the specialized light-sensitive tissue at the back of the eye that detects light and color.
In children with retinoblastoma, the disease often affects only one eye. However, one out of three children with retinoblastoma develops cancer in both eyes. The most common first sign of retinoblastoma is a visible whiteness in the pupil called "cat's eye reflex" or leukocoria. This unusual whiteness is particularly noticeable in dim light or in photographs taken with a flash. Other signs and symptoms of retinoblastoma include crossed eyes or eyes that do not point in the same direction (strabismus), which can cause squinting; a change in the color of the colored part of the eye (iris); redness, soreness, or swelling of the eyelids; and blindness or poor vision in the affected eye or eyes.
Retinoblastoma is often curable when it is diagnosed early. However, if it is not treated promptly, this cancer can spread beyond the eye to other parts of the body. This advanced form of retinoblastoma can be life-threatening.
When retinoblastoma is associated with a genetic change (mutation) that occurs in all of the body's cells, it is known as hereditary (or germinal) retinoblastoma. People with this form of retinoblastoma typically develop cancer in both eyes and also have an increased risk of developing several other cancers outside the eye. Specifically, they are more likely to develop a cancer of the pineal gland in the brain (pineoblastoma), a type of bone cancer known as osteosarcoma, cancers of soft tissues (such as muscle) called soft tissue sarcomas, and an aggressive form of skin cancer called melanoma.
Frequency Retinoblastoma is diagnosed in 250 to 350 children per year in the United States. It accounts for about 4 percent of all cancers in children younger than 15 years.
Mutations in the RB1 gene are responsible for most cases of retinoblastoma. RB1 is a tumor suppressor gene, which means that it normally regulates cell growth and stops cells from dividing too rapidly or in an uncontrolled way. Most mutations in the RB1 gene prevent it from making any functional protein, so cells are unable to regulate cell division effectively. As a result, certain cells in the retina can divide uncontrollably to form a cancerous tumor. Some studies suggest that additional genetic changes can influence the development of retinoblastoma; these changes may help explain variations in the development and growth of retinoblastoma and other types of tumors in different people.
A small percentage of retinoblastomas are caused by deletions in the region of chromosome 13 that contains the RB1 gene. Because these chromosomal changes involve several genes in addition to RB1, affected children usually also have intellectual disability, slow growth, and distinctive facial features (such as prominent eyebrows, a short nose with a broad nasal bridge, and ear abnormalities).
We are compiling a list of websites to help you understand genetics and genetic test results. If you would like to suggest other resources for this section, please feel free to connollyj1 [at] chop.edu (send us an email)!
INFORMATION ABOUT GENETICS AND GENETIC TESTING:
Genetics Home Reference
Consumer-friendly information about the effects of genetic variations on human health. Federally-supported resources, include reviews of more than 800 genetic diseases and more than 1000 genes.
Learning Resources from the NHGRI
Lots of very good resources from the NHGRI, including major sections about The Human Genome Project, Facts Sheets, and educational resources for teachers and students.
Find a Genetic Counselor
The National Society of Genetic Counselors have a searchable database of genetic counselors. Their website also includes some education materials for patients and healthcare professionals.
NHGRI Talking Glossary
Talking glossary of genetic terms developed by the National Human Genome Research Institute. A huge range of definitions is provided by researchers from around the world.
Help Me Understand Genetics
Help Me Understand Genetics is a handbook from the National Institutes of Health that contain useful information about genetics in clear language and provides links to even more online resources. The entire handbook can also be downloaded as a pdf.
Genetic and Rare Diseases Information Center (GARD)
A joint project from The Office of Rare Diseases Research (ORDR) and the National Human Genome Research Institute (NHGRI) that provides searchable information about genetic conditions and rare diseases. It also includes a list of FDA-Approved drugs and other medical products for treating rare disease.
National Organization for Rare Disorders - Resources for Parents/Families
The National Organization for Rare Disorders (NORD) is a volunteer organization dedicated to empowering the rare disease community. Again, they have some very nice web resources.
Ethical, Legal and Social Implications Research Program
The ELSI Research Program supports examinations and investigations of the ethical, legal and social implications of genetics research.
Genetic Information Nondiscrimination Act of 2008
The Genetic Information Nondiscrimination Act of 2008, also referred to as GINA, is a new federal law that protects Americans from being treated unfairly because of differences in their DNA that may affect their health.
Learn.Genetics, University of Utah
Excellent resources, especially for those involved in education. Includes a catalog of animations, videos, interactive features, and virtual labs.
Dolan DNA Leaning Center
The DNALC provides genetics learning resources for teachers and students.
INFORMATION FOR RESEARCHERS:
ClinVar: ACMG Recommendations for Reporting of Incidental Findings in Clinical Exome and Genome Sequencing
Clinvar's dedicated ACMG page - a useful jumping-off point to the Genetic Testing Registry, OMIM, MedGen, and local ClinVar pages for each gene.
Gene Reviews (updated September, 2018)
What is the purpose of this information?
Our aim is to provide information about why we do genetic testing. We try to answer some common questions and offer guidance on some personal and practical issues. This information is for anybody with questions about genetic testing for any of the diseases and drugs listed in this site.
Are there geographical differences in testing, service or treatment?
Different centers have different policies in terms of how tests are administered and results shared. However, the results discussed in this document should be relevant to most individuals tested for risk of developing genetic disease.
How is this paid for?
If you received this test as part of the eMERGE research study, neither you nor your insurance company will have to pay anything toward this test
When was this content last updated?
October 10, 2018.