A trisomy is a term for a genetic condition in which there are three chromosomes instead of the usual pair.
Trisomy 21, more commonly known as Down Syndrome, is a condition caused by an extra copy of chromosome 21. Unfortunately, miscarriage occurs in about 30% of pregnancies with Down Syndrome. Those children born with Down Syndrome will need extra medical care depending on the child’s specific health problems. Most children with Down Syndrome have intellectual disabilities that range from mild to moderate.
Trisomy 18, or Edwards Syndrome, is caused when a baby has three copies of chromosome 18, instead of two. Unfortunately, pregnancies with Edwards Syndrome are at high risk of miscarriage and most babies born with Edwards Syndrome die within the first few weeks of life while less than 10% live beyond one year. Infants with Edwards Syndrome have severe intellectual disabilities and birth defects typically involving the heart, brain, and kidneys, and external abnormalities such as cleft lip/palate, small head, club feet, underdeveloped digits, and small jaw.
Trisomy 13, or Patau Syndrome, is caused when a baby has three copies of chromosome 13, instead of two. Unfortunately, pregnancies diagnosed with Patau Syndrome are at high risk for miscarriage or stillbirth, and most babies born with Patau Syndrome will not survive beyond the first weeks of life. Babies with Patau Syndrome may have heart defects, brain or spinal cord problems, extra fingers and/or toes, cleft lip/cleft palate, and weak muscle tone. Many babies have birth defects of other organs as well.
Trisomy 22 is caused when a baby has three copies of chromosome 22, instead of two. Trisomy 22 is very rare. Unfortunately, pregnancies diagnosed with trisomy 22 are at very high risk of miscarriage or stillbirth.
Trisomy 16 is caused when a baby has three copies of chromosome 16, instead of two. Full trisomy 16 is incompatible with life and unfortunately most women will miscarry in the first trimester.
Trisomy 9 is caused when a baby has three copies of chromosome 9, instead of two. Babies born with trisomy 9 commonly have defects in the heart, kidneys, and musculoskeletal system.
167 B, PCSIR II, Lahore, Pakistan
April 11, 2017