BACK TOTOP Browse A-ZSearchBrowse A-ZABCDEFGHIJKLMNOPQRSTUVWXYZ0-9 E-mail FormEmail ResultsName:Email address:Recipients Name:Recipients address:Message: Print-FriendlyBookmarksbookmarks-menuTrisomy 18Edwards syndromeTrisomy 18 is a genetic disorder in which a person has a third copy of material from chromosome 18, instead of the usual 2 copies. Rarely, the extra material may be attached to another chromosome (translocation). Most cases are not passed down through families. Instead, the problems that lead to this condition occur in either the sperm or the egg that forms the fetus.ChromosomeChromosomes are structures found in the center (nucleus) of cells that carry long pieces of DNA. DNA is the material that holds genes. It is the bu...ImageRead Article Now Book Mark Article Causes Trisomy 18 occurs in 1 in 6000 live births. It is 3 times more common in girls than boys. The syndrome occurs when there is extra material from chromosome 18. The extra material affects normal development.Trisomy 18: the presence of an extra (third) chromosome 18 in all of the cells. Mosaic trisomy 18: the presence of an extra chromosome 18 in some of the cells. Partial trisomy 18: the presence of a part of an extra chromosome 18 in the cells.Most cases of Trisomy 18 are not passed down through families (inherited). Instead, the events that lead to trisomy 18 occur in either the sperm or the egg that forms the fetus. Symptoms Symptoms may include:Clenched hands Crossed legs Feet with a rounded bottom (rocker-bottom feet) Low birth weight Low birth weightSmall for gestational age means that a fetus or an infant is smaller or less developed than normal for the baby's sex and gestational age. Gestation...Read Article Now Book Mark Article Low-set ears Mental delay Poorly developed fingernails Small head (microcephaly) MicrocephalyMicrocephaly is a condition in which a person's head size is much smaller than that of others of the same age and sex. Head size is measured as the ...ImageRead Article Now Book Mark Article Small jaw (micrognathia) MicrognathiaMicrognathia is a term for a lower jaw that is smaller than normal.ImageRead Article Now Book Mark Article Undescended testicle Undescended testicleUndescended testicle occurs when one or both testicles fail to move into the scrotum before birth.ImageRead Article Now Book Mark Article Unusual shaped chest (pectus carinatum) Pectus carinatumPectus carinatum is present when the chest protrudes over the sternum. It is often described as giving the person a bird-like appearance.ImageRead Article Now Book Mark Article Exams and Tests An exam during pregnancy may show an unusually large uterus and extra amniotic fluid. There may be an unusually small placenta when the baby is born. A physical exam of the infant may show unusual facial features and fingerprint patterns. X-rays may show a short breast bone.Amniotic fluidAmniotic fluid is a clear, slightly yellowish liquid that surrounds the unborn baby (fetus) during pregnancy. It is contained in the amniotic sac....ImageRead Article Now Book Mark Article Chromosome studies will show trisomy 18. The chromosome abnormality may be present in every cell or present in only a certain percentage of the cells (called mosaicism). Studies may also show part of the chromosome in some cells. Rarely, part of the chromosome 18 becomes attached to another chromosome. This is called translocation.Chromosome studiesKaryotyping is a test to examine chromosomes in a sample of cells. This test can help identify genetic problems as the cause of a disorder or diseas...ImageRead Article Now Book Mark Article TranslocationTranslocation means a change in location. It often refers to genetics, when part of a chromosome is transferred to another chromosome. Chromosomes ...ImageRead Article Now Book Mark Article Other signs include:Hole, split, or cleft in the iris of the eye (coloboma) ColobomaColoboma of the iris is a hole or defect of the iris of the eye. Most colobomas are present since birth (congenital).ImageRead Article Now Book Mark Article Separation between the left and right side of the abdominal muscle (diastasis recti) Diastasis rectiDiastasis recti is a separation between the left and right side of the rectus abdominis muscle. This muscle covers the front surface of the belly ar...ImageRead Article Now Book Mark Article Umbilical hernia or inguinal herniaUmbilical herniaAn umbilical hernia is an outward bulge in the area around the belly button. It occurs when internal organs or the abdominal lining bulges through t...ImageRead Article Now Book Mark Article Inguinal herniaA hernia is a sac formed by the lining of the abdominal cavity (peritoneum). The sac comes through a hole or weak area in the strong layer of the be...ImageRead Article Now Book Mark Article There are often signs of congenital heart disease, such as:Congenital heart diseaseCongenital heart disease (CHD) is a problem with the heart's structure and function that is present at birth.ImageRead Article Now Book Mark Article Atrial septal defect (ASD) Atrial septal defectAtrial septal defect (ASD) is a heart defect that is present at birth (congenital). As a baby develops in the womb, a wall (septum) forms that divide...ImageRead Article Now Book Mark Article Patent ductus arteriosus (PDA) Patent ductus arteriosusPatent ductus arteriosus (PDA) is a condition in which the ductus arteriosus does not close. The word "patent" means open. The ductus arteriosus is ...ImageRead Article Now Book Mark Article Ventricular septal defect (VSD) Ventricular septal defectVentricular septal defect is a hole in the wall that separates the right and left ventricles of the heart. Ventricular septal defect is one of the m...ImageRead Article Now Book Mark Article Tests may also show kidney problems, including:Horseshoe kidney Hydronephrosis HydronephrosisHydronephrosis is swelling of one kidney due to a backup of urine. This problem may occur in one kidney.ImageRead Article Now Book Mark Article Polycystic kidneyPolycystic kidneyPolycystic kidney disease (PKD) is a kidney disorder passed down through families. In this disease, many cysts form in the kidneys, causing them to ...ImageRead Article Now Book Mark Article Treatment There are no specific treatments for trisomy 18. Which treatments are used depend on the person's individual condition. Support Groups Support groups include:Support Organization for Trisomy 18, 13 and Related Disorders (SOFT): trisomy.org Trisomy 18 Foundation: www.trisomy18.org Hope for Trisomy 13 and 18: www.hopefortrisomy13and18.org Outlook (Prognosis) One half of infants with this condition do not survive beyond the first week of life. Nine out of ten children will die by 1 year of age. Some children have survived to the teenage years, but with serious medical and developmental problems. Possible Complications Complications depend on the specific defects and symptoms.Complications may include:Breathing difficulty or lack of breathing (apnea) Deafness Feeding problems Heart failure Seizures Vision problems When to Contact a Medical Professional Genetic counseling can help families understand the condition, the risks of inheriting it, and how to care for the person. Prevention Tests can be done during pregnancy to find out if the child has this syndrome.Genetic counseling is recommended for parents who have a child with this syndrome and who want to have more children.Open ReferencesReferencesBacino CA, Lee B. Cytogenetics. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 98.Madan-Khetarpal S, Arnold G. Genetic disorders and dysmorphic conditions. In: Zitelli BJ, McIntire SC, Nowalk AJ, eds. Zitelli and Davis' Atlas of Pediatric Physical Diagnosis. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 1.AllVideoImagesTogSyndactyly - illustration Fingers or toes (digits) may be fused together (syndactyly) or the webbing between them (inter-digital webbing) may extend far up the digits. Syndactyly is seen commonly between the second and third toes, and may sometimes be associated with a syndrome.SyndactylyillustrationSyndactyly - illustration Fingers or toes (digits) may be fused together (syndactyly) or the webbing between them (inter-digital webbing) may extend far up the digits. Syndactyly is seen commonly between the second and third toes, and may sometimes be associated with a syndrome.SyndactylyillustrationRelated Information Chromosome(Special Topic) Review Date: 7/30/2021 Reviewed By: Anna C. Edens Hurst, MD, MS, Associate Professor in Medical Genetics, The University of Alabama at Birmingham, Birmingham, AL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- © 1997- All rights reserved. A.D.A.M. content is best viewed in IE9 or above, Firefox and Google Chrome browser.Content is best viewed in IE9 or above, Firefox and Google Chrome browser.