
 
 What Is Trisomy 18? Trisomy 18, also known as Edwards syndrome, is a condition which is caused by a error in cell division, known as meiotic disjunction. Trisomy 18 occurs in about 1 out of every 2500 pregnancies in the United States, about 1 in 6000 live births. The numbers of total births increase significantly when stillbirths are factored in that occur in the 2nd and 3rd trimesters of pregnancy. Unlike Down syndrome, which also is caused by a chromosomal defect, the developmental issues caused by Trisomy 18 are associated with medical complications that are more potentially life-threatening in the early months and years of life. 50% of babies who are carried to term will be stillborn, with baby boys having higher stillbirth rate than baby girls. At birth, intensive care admissions in Neonatal units are most common for infants with Trisomy 18. Again, baby boys will experience higher mortality rates in this neonatal period than baby girls, although those with higher birth weights do better across all categories. Some children will be able to be discharged from the hospital with home nursing support for their families. And although less than 10 percent survive to their first birthdays, some children with Trisomy 18 can enjoy many years of life with their families, reaching milestones and being involved with their community. A small number of adults (usually girls) with Trisomy 18 have and are living into their twenties and thirties, although with significant developmental delays that do not allow them to live independantly without assisted caregiving. Frequently Asked Questions What causes Trisomy 18? Are there different types of Trisomy 18? What are the characteristics of Trisomy 18? What causes Trisomy 18? 
 
 At conception, 23 chromosomes from the father and 23 chromosomes from the mother combine to create a baby with a set of 46 chromosomes in each cell. A trisomy occurs when a baby has three #18 chromosomes instead of the normal two. This is something that happens at conception. And although many parents worry about this, it is important to know that parents have done nothing before or during pregnancy to cause this disorder in their child. Back to top of page 
 
 Are there different types of Trisomy conditions? 
 
 The most common trisomy is Trisomy 21, also known as Down syndrome, where a baby has three of the twenty-first chromosome. Trisomy 18 is the second most common trisomy and occurs when a baby has three of the eighteenth chromosome. This results in 47 chromosomes instead of the normal 46 in the affected cells. It is this extra genetic material that causes the problems associated with Trisomy 18. The third most common is Trisomy 13, also known as Patau syndrome. 
 
 
 
 While there are different types of Trisomy 18, this does not mean one is better for a child than another. With each type, there is a range of possibilities. Some children are medically fragile while others thrive; some children walk while others are confined to wheelchairs. It is hard to say how the extra chromosome will impact an individual child from the genetic diagnosis alone. Types of Trisomy 18: Full Trisomy 18: The most common type of Trisomy 18 (occurring in about 95% of all cases) is full Trisomy. With full Trisomy, the extra chromosome occurs in every cell in the baby's body. This type of trisomy is not hereditary. It is not due to anything the parents did or did not do—either before or during pregnancy. 
 
 
 
 
 
 The most common type of Trisomy 18 (occurring in about 95% of all cases) is full Trisomy. With full Trisomy, the extra chromosome occurs in every cell in the baby's body. This type of trisomy is not hereditary. It is not due to anything the parents did or did not do—either before or during pregnancy. Partial Trisomy 18: Partial trisomies are very rare. They occur when only part of an extra chromosome is present. Some partial Trisomy 18 syndromes may be caused by hereditary factors. Very rarely, a piece of chromosome 18 becomes attached to another chromosome before or after conception. Affected people have two copies of chromosome 18, plus a "partial" piece of extra material from chromosome 18. 
 
 
 
 
 
 Partial trisomies are very rare. They occur when only part of an extra chromosome is present. Some partial Trisomy 18 syndromes may be caused by hereditary factors. Very rarely, a piece of chromosome 18 becomes attached to another chromosome before or after conception. Affected people have two copies of chromosome 18, plus a "partial" piece of extra material from chromosome 18. Mosaic Trisomy 18: Mosaic trisomy is also very rare. It occurs when the extra chromosome is present in some (but not all) of the cells of the body. Like full Trisomy 18, mosaic Trisomy is not inherited and is a random occurrence that takes place during cell division. 
 
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 What are the characteristics of Trisomy 18? 
 
 The genetic material from the extra eighteenth chromosome can cause a variety of problems with varying severity. Just as children with Down syndrome can range from mildly to severely affected, the same is true for children with Trisomy 18. This means that there is no hard and fast rule about what Trisomy 18 will mean for your child. However, statistics show that there is a high mortality rate for children with Trisomy 18 before or shortly after birth. Typical characteristics of Trisomy 18 include: Heart defects: 
 
 VSD (Ventricular Septal Defect): a hole between the lower chambers 
 
 
 
 ASD (Atrial Septal Defect): a hole between the upper chambers 
 
 
 
 Coarctation of the aorta: a narrowing of the exit vessel from the heart 
 
 Kidney problems 
 
 Part of the intestinal tract is outside the stomach (omphalocele) 
 
 The esophagus doesn’t connect to the stomach (esophageal artesia) 
 
 Excess amniotic fluid (polyhydramnios) 
 
 Clenched hands 
 
 Pocket of fluid on the brain (choroid plexus cysts) 
 
 Rocker bottom feet 
 
 Delayed growth 
 
 Small jaw (mycrognathia) 
 
 Small head (microcephaly) 
 
 Low-set ears 
 
 Strawberry-shaped head 
 
 Severe developmental delays 
 
 Umbilical or inguinal hernia 
 
 
 
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 ||||| The three-year-old daughter of Republican presidential hopeful Rick Santorum has been admitted to Children's Hospital of Philadelphia and the candidate has cancelled his Sunday morning campaign events to be at her side. 
 
 Santorum campaign spokesman Hogan Gidley said Saturday night that the former Pennsylvania senator and his wife, Karen, were with Bella at CHOP. Gidley said Santorum planned to return to campaigning as soon as possible in Florida, where the Republican primary is Tuesday. 
 
 Bella Santorum has Trisomy 18, a genetic condition in which a child has a third copy of material from chromosome 18, instead of the usual two, causing a wide array of physical and mental problems. 
 
 Bella was not expected to survive until her first birthday - half of infants with Trisomy 18 do not survive their first week, according the National Institutes of Health. Some children have lived to their teenage years, but with significant medical and developmental issues. 
 
 The Santorums have been frequent visitors to CHOP with their daughter, and concerns over Isabella's health have canceled previous Santorum campaign events. 
 
 During his campaign, Santorum and his wife have spoken openly about the challenges and rewards of raising a child with such a condition. 
 
 The Santorums have six other children; they lost a baby boy, Gabriel, shortly after his birth in 1996. Bella was born in 2008; two years later, Santorum wrote about her in an Inquirer column. 
 
 "All children are a gift that comes with no guarantees," he wrote. "While Bella's life may not be long, and though she requires our constant care, she is worth every tear." 
 
 Bella, whose full name is Isabella Maria Santorum, has become a symbol of his pro-life stance, as he claimed that most infants diagnosed in the womb with Trisomy 18 are aborted. 
 
 "I have a little girl who's 3 1/2 years old," he told Christian conservatives in Iowa before winning that lead-off contest. 
 
 "I don't know whether her life is going to be measured - it's always been measured - in days and weeks. Yet here I am. . .because I feel like I wouldn't be a good dad if I wasn't out here fighting for a country that would see the dignity in her and every other child." 
 
 When voters ask him about her, he calls the decision to campaign "gut-retching" but says he goes forward for all special needs families. 
 
 "You think she's fine, and then one cold and she's this close to dying," he told The Washington Post last year in an interview. 
 
 In October, he missed one of Bella's surgeries to participate in a debate, and told the audience that he planned to take an all-night flight home from Las Vegas to be with her. 
 
 "I look at the simplicity and love she emits," Santorum said in a web video his campaign released after his scheduling drew questions, "and it's clear to me we're the disabled ones." 
 
 Santorum largely has kept his daughter off the campaign schedules, preferring her to stay home with her mother. But Bella did join 
 
 Santorum for a few days around Iowa's straw poll in August, and she joined her family in Charleston, S.C., the day of its primary. She didn't join her six siblings for the public speech. She stayed backstage. 
 
 Santorum had been scheduled to appear on NBC's "Meet the Press" and to attend church in Miami. He was in the Philadelphia area as recently as Friday night to attend a campaign fundraiser in Chester County. 
 
 This article includes information from the Associated Press.
– Rick Santorum's 3-year-old daughter, Isabella, who suffers from the genetic condition Trisomy 18, was hospitalized yesterday, causing Santorum to cancel his campaign events this morning to travel to Philadelphia and be by her side, reports the Philadelphia Inquirer. Half of babies with Trisomy 18, a chromosomal defect, are stillborn, and fewer than 10% make it to their first birthday. "All children are a gift that comes with no guarantees," Santorum wrote in a newspaper column in 2010. "While Bella's life may not be long, and though she requires our constant care, she is worth every tear." Isabella's condition has caused frequent visits to the Children's Hospital of Philadelphia. "I look at the simplicity and love she emits," Santorum said in a recent web video, "and it's clear to me we're the disabled ones." Santorum's campaign say they expect him to return to Florida later today.