Trisomy 2 mosaicism
- Mosaic trisomy 2
Your QuestionOur daughter was recently diagnosed with mosaic trisomy 2. Since birth she has always had an undiagnosed syndrome. We felt relieved that we finally knew what she was born with but we have not been able to find any information about it. What can you provide us?
We have identified the following information that we hope you find helpful. If you still have questions, please contact us.
Questions on this page
- What are chromosomes?
- What is a karyotype?
- What is a chromosome anomaly?
- What is a chromosome trisomy? What is mosaicism?
What is trisomy 2 mosaicism?
- Have cases of live born infants with trisomy 2 mosaicism been reported in the medical literature?
- How can I learn about the features and outcomes that have been associated with specific cases of trisomy 2 mosaicism?
- How can I learn about research involving trisomy 2 mosaicism?
Note: This information is meant for individuals with trisomy 2 mosaicism and their families. Trisomy 2 mosaicism may also be encountered during pregnancy as a finding following chorionic villus sampling. In these situations the trisomic cells are most often confined to the placenta and the pregnancy results in a healthy infant. Further investigation is warranted however, because in a small percentage of cases this finding can be associated increased pregnancy risks. Questions regarding trisomy 2 mosaicism should be discussed with a genetic professional. Click here to visit GeneTests to search for a genetics professional near you.
More information on chromosomes is available from Genetics Home Reference.
Today additional chromosome test are available, such as FISH (fluorescence in situ hybridization) and comparative genomic hybridization arrays. Click on the links above to learn more about these genetic tests.
You can find additional information on chromosome anomalies in general at the following Web sites.
The National Human Genome Research Institute, part of the National Institutes of Health (NIH), has developed a fact sheet on chromosome abnormalities, which may be helpful to you. To read this information, visit the link below.
MEDLINEplus, the National Library of Medicine Web site designed to direct you to information and resources that help you research your health questions, provides further information about chromosomes at the following link:
When a trisomy affects only a subset of cells, this is called 'mosaicism.' In mosaic trisomies the percentage of affected body cells and location of affected cells vary from person to person. Because of this it is difficult to compare people with the same mosaic trisomy as they tend to be be very differently affected.
More information on chromosome mosaicism can be found by visiting the Centre for Genetics Education Web page on this topic at the following link:
When trisomy 2 mosaicism is detected during early pregnancy with chorionic villus sampling (CVS), the affected cells may be confined only to the placenta, and not present in the fetus. Amniocentesis is typically recommended to confirm this, and monitoring is still warranted due to an increased risk for intrauterine growth restriction, low amniotic fluid level (oligohydramnios), or other complications including stillbirth.
Intrauterine growth retardation
Underdevelopment of the corpus callosum
Neural tube defects
Minor differences in facial appearance (e.g., downturned corners of the mouth, epicanthal folds, wide spaced eyes)
Atrial and ventricular septal defect
Short hands and feet with prominent palmar pads
Hypopigmented patches of skin
Wide placed nipples
Feet with a rounded bottom (rocker bottom feet)
Additionally, you can find relevant articles on trisomy 2 mosaicism through PubMed, a searchable database of biomedical journal articles. Although not all of the articles are available for free online, most articles listed in PubMed have a summary available. To obtain the full article, contact a medical/university library or your local library for interlibrary loan. You can also order articles online through the publisher’s Web site. Using "trisomy 2 mosaicism" or "mosaic trisomy 2" as your search term should help you locate articles. View our sample PubMed search for this condition here.
The National Library of Medicine (NLM) Web site has a page for locating libraries in your area that can provide direct access to these journals (print or online). The Web page also describes how you can get these articles through interlibrary loan and Loansome Doc (an NLM document-ordering service). You can access this page at the following link: http://nnlm.gov/members/. You can also contact the NLM toll-free at 888-346-3656 to locate libraries in your area.
The National Human Genome Research Institute (NHGRI) has completed an evaluation of patients with unresolved chromosome abnormalities. Further information about this study can be accessed through ClinicalTrials.gov, a database developed by the U.S. National Institutes of Health, through the National Library of Medicine to provide patients, family members, and members of the public with current information on clinical research studies. To read about this study, visit the hyperlink below. After you click on the study, review its information to determine if it provides you with useful information. Use the study’s contact information to learn more.
To locate information resulting from the completed study entitled, 'Evaluation of Patients with Unresolved Chromosome Abnormalities' (study ID numbers 970045, 97-HG-0045; NLM Identifier NCT00001639), you can either e-mail or call the National Library of Medicine (NLM) Customer Service. Include the title of the study, the study ID number, and the NLM Identifier, and a librarian at NLM can assist you in searching the medical literature for published results on the completed clinical trial.
National Library of Medicine Customer Service
Oftentimes parents ask us how they can find a researcher who is interested in studing their child's rare chromosome anomaly. We recognize that it can be a challenge to find a researcher who is available and has the funds needed to research a specific condition. Still, we have identified the following resources which may be helpful.
The Genetic Alliance, an international coalition composed of more than 750 advocacy organizations, has created online tools that discuss how to get researchers interested in a disease. To review the information, visit the following link and scroll down to the research section:
ResearchMatch is a free national research registry designed to bring together patients, healthy volunteers and researchers. Anyone from the United States can register with ResearchMatch, and a parent, legal guardian, or caretaker may register on behalf of a volunteer. Researchers from participating institutions use the ResearchMatch database to search for patients or healthy volunteers who meet the study criteria. Many studies are looking for healthy people of all ages, while some are looking for people with specific illnesses. ResearchMatch was developed by major academic institutions across the country and is funded by the National Center for Research Resources (NCRR), a center of the National Institutes of Health (NIH), the primary Federal agency for conducting and supporting medical research.
- Gupta S et al. Trisomy 2 mosaicism in hypomelanosis of Ito. Am J Med Genet Part A. 2007;
- McKinlay Gardner RJ, Southerland GR. Chromosome Abnormalities and Genetic Counseling. New York, NY: Oxford University Press, Inc; 2004;
- Chen CP, et. al. Prenatal diagnosis of mosaic trisomy 2 associated with abnormal maternal serum screening, oligohydramnios, intrauterine growth restriction, ventricular septal defect, preaxial polydactyly, and facial dysmorphism. Taiwan J Obstet Gynecol. September, 2013; 52(3):395-400.
- Schinzel A., . Catalogue of Unbalanced Chromosome Aberrations in Man, 2nd ed. Walter de Gruyter GmbH & Co; 2001;
- Mihci E et al.,. Clinical Dysmorphology. The phenotypic spectrum of trisomy 2: Report of two new cases. 2009;
- Seller MJ et al.,. A trisomy 2 fetus with severe neural tube defects and other abnormalities. Clinical dysmorphology. 2004;
- Sifakis S, Staboulidou I, Maiz N, Velissariou V, Nicolaides KH. Outcome of pregnancies with trisomy 2 cells in chorionic villi.. Prenat Diagn. 2010 Apr;