Prenatal Genetic Screening Tests

Abdominal wall defects called gastroschisis and omphalocele affect about 1 in 5,000 births in the U.S. Affected babies have intestines that protrude outside the body through an opening in the abdominal wall or through a hernia in the umbilical area. Surgery can help correct these defects.

Cystic fibrosis (CF) is a genetic disease. About 30,000 children and adults in the United States have the disorder. Cystic fibrosis severely affects breathing and digestion. It is caused by an abnormal gene that makes the body produce thick mucus in the lungs. CF is an autosomal recessive disorder, meaning that both parents must be carriers for a child to be at risk. If you are found to be a carrier, then your partner will also be offered carrier testing.

About 1 in 800 babies in the U.S. is born with Down syndrome, which is caused by an extra copy of chromosome 21. Affected children have varying degrees of mental intellectual disabilities, characteristic facial features and, oftentimes, have heart defects in addition to other physical problems.

Fragile X syndrome is the most common inherited cause of autism and intellectual disability. Symptoms are variable from mild to severe. Females usually have milder symptoms than males. Approximately 1 in every 3,600 boys and 1 in every 6,000 girls is born with Fragile X. Fragile X is an X-linked disorder; the gene is on the X chromosome.

In the U.S., 1 in 200 babies is born with a congenital heart defect. The effects can range from mild to life-threatening. Many babies require surgery to help correct the defect.

Open neural tube defects, often called spina bifida, affects the backbone and sometimes the spinal cord. Children with spina bifida may have varying degrees of leg paralysis and bladder and bowel control problems. Anencephaly is a severe form of neural tube defect and is a fatal condition in which a baby is born with a severely underdeveloped brain and skull.

Spinal muscular atrophy or SMA is the most common inherited cause of infant death. It affects a child’s ability to control their muscles, including those involved in breathing, eating, crawling and walking. One in every 6,000 to 10,000 babies born in the U.S. has SMA. Spinal muscular atrophy is an autosomal recessive disorder, meaning that both parents must be carriers for a child to be at risk. If you are found to be a carrier, then your partner will also be offered carrier testing.

About 1 in 8,000 babies in the U.S. is born with Trisomy 13, which is caused by an extra copy of chromosome 13. Affected babies have severe mental intellectual disabilities, heart development delays and other birth defects. Most babies with Trisomy 13 will die within the first year of life, if not before delivery.

About 1 in 6,000 babies in the U.S. is born with Trisomy 18, which is caused by an extra copy of chromosome 18. Affected babies have severe mental intellectual disabilities, heart defects and other birth defects. Most babies with Trisomy 18 will die within the first year of life, if not before delivery.