Trisomy 18 Affects Santorum Daughter, Many Others

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News that the three-year-old daughter of Rick and Karen Santorum was admitted to Children’s Hospital of Philadelphia has significance beyond the fact that her father is a candidate for president of the United States. Isabella Maria Santorum, born in 2008, has trisomy 18, a serious genetic condition that is fatal for 90 percent of babies before they reach their first birthday.

Trisomy 18 is also known as Edwards syndrome

One out of every 3,000 live births in the United States involves a child who has trisomy 18, a condition that is caused by a chromosomal defect in which the child has an extra number 18 chromosome (either a partial or full chromosome); that is, three instead of the normal two. About half of the babies with trisomy 18 are stillborn.

Other conditions caused by chromosomal defects include Down syndrome, which is the most common condition in this category (affecting 1 in 800 babies), Patau syndrome, which affects about one in 10,000 births, and Turner syndrome, which affects only girls (one in 2,500 births), according to the March of Dimes.

Unlike Down syndrome, in which life expectancy has improved to where about 50 percent of people with the condition live to 50 and beyond, trisomy 18 is associated with medical complications that are potentially life-threatening during the early months and years of life.

According to the Trisomy 18 Foundation, although less than 10 percent of babies born with trisomy 18 live to celebrate their first birthdays, some children do survive for many years, while a small percentage (usually females) reach adulthood. Children who do survive typically face a number of physical and mental challenges, however, and require supervised care.

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Types of trisomy 18
Of the three types of trisomy 18, the most common is full trisomy 18, which occurs in about 95 percent of cases. Children with full trisomy have an extra chromosome 18 in every cell of their body. Because the condition is not hereditary, parents do not pass the disease along to their children and the condition cannot be passed on.

A much rarer form is called partial trisomy 18, and this type may have hereditary components. Individuals with partial trisomy 18 have two copies of chromosome 18 plus a partial piece of excess material from chromosome 18.

Mosaic trisomy 18 is also rare and occurs when only some of the cells have an extra chromosome 18. This form of trisomy 18 also is not inherited.

Signs and symptoms of trisomy 18
The severity of signs and symptoms associated with trisomy 18 can range from mild to severe. Some of those signs and symptoms include

  • Heart defects, which may include a hole between the lower chambers (ventricular septal defect) or upper champbers (atrial septal defect), or a narrowing of the aorta (coarctation of the aorta)
  • Delayed growth
  • Small or strawberry-shaped head
  • Small jaw
  • Kidney problems
  • Digestive tract defects, including an esophagus that does not connect to the stomach (esophageal artesia) or presence of part of the intestinal tract outside the stomach (omphalocele)
  • Severe developmental delays
  • Clenched hands
  • Rocker bottom feet

Having a child with trisomy 18 is a physical, emotional, and financial challenge for parents. According to a recent article in the Philadelphia Inquirer, Rick Santorum was quoted as saying that “While Bella’s life may not be long, and though she requires our constant care, she is worth every tear.” The Trisomy 18 Foundation provides information about how parents can find support.

SOURCES:
March of Dimes
Philadelphia Inquirer
Trisomy 18 Foundation

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