Babies with trisomy 13 have three copies of chromosome 13 and have severe intellectual disabilities. They often have birth defects involving the heart, brain, and kidneys. Visible abnormalities include extra fingers and/or toes or an opening in the lip, with or without an opening in the palate. Given the severe disabilities, most pregnancies affected by trisomy 13 will miscarry. If born alive, most affected babies with trisomy 13 will pass away within the first few weeks of life. About 10 percent survive to their first birthday. Trisomy 13 occurs in approximately 1 in 5,000 live births.