Triploidy in Focus: Understanding the Genetic Disorder

Triploidy is a rare condition that affects between 1 and 3 percent of all pregnancies. Triploidy is a chromosomal abnormality. Normally you get two sets of chromosomes from your mother and father, each containing 23. Added together this gives your cells a total of 46 chromosomes per cell. With triploidy all cells have a third set of chromones, making the total amount of chromosomes per cell 69. There are no added risk factors for your baby to have triploidy. If you have one child with triploidy it does not raise the risk of subsequent pregnancies to be affected. It is not a hereditary condition.

Most babies that have triploidy do not make it to birth. It is common for pregnancies to end in miscarriage. If the baby does make it to term and is born, they usually do not live for more than a few days. Triploidy is caused by a few different things. It can happen from two sperm fertilizing one egg. A sperm with extra chromosomes fertilizing an egg. Or it can be caused by an egg with extra chromosomes being fertilized by a normal sperm.

Common defects that can occur from triploidy are slow growth, heart defects, or neural tube defects. Other symptoms can include abnormal brain development, cystic kidney disease, growth abnormalities of the intestines, spinal cord, liver, or gallbladder, fused fingers and toes, short stature, wide spaced eyes, cleft lip, seizures, or intellectual disability. Triploidy can also cause symptoms in the mother. Triploidy can raise the risk of a mother suffering from preeclampsia. Which can cause high blood pressure. Symptoms of high blood pressure include headaches, dizziness, irritability, nausea, vomiting, upper belly pain, blurry vision, and sensitivity to light. Other symptoms that can affect the mother with triploidy are a placenta full of cysts, swelling, and excess albumin in urine.

Triploidy can be suspected at a routine ultrasound. Routine ultrasounds happen to make sure that a baby is growing on track for how old they are. A routine ultrasound can show if there are unusual body parts, low amniotic fluid, or less growth of the baby. If your doctor suspects there to be an issue they may request you do further testing. You can do an amniocentesis which is when a sample of the amniotic fluid is taken with a needle. Another way your doctor can diagnose triploidy is with chorionic villus sampling. Which is where they take a sample of your placenta. After birth your doctor can do genetic testing on your baby to check for chromosomal defects. A microarray test where a blood sample is taken cannot help to diagnose triploidy.

There is no cure for this condition. Pregnancies usually end in miscarriage, or early infant death. Treatment can support care for the parents, family members, and caregivers. If the baby is born treatment can be done to reduce the baby’s life threatening symptoms. This could include surgeries, or medications. Supportive care can also be done for the baby after birth to make them comfortable for their lifetime.

Mosaicism is a type of triploidy. This type of triploidy causes only a few cells to have more chromosomes and the other cells have normal amounts of chromosomes. This can reduce the severity and the number of growth abnormalities. Babies with mosaicism may last a few years. Trisomy is similar to triploidy but not a different type. Trisomy is when only certain pairs of chromosomes get extra chromosomes in every cell. Examples of conditions caused by trisomy are Patau syndrome, Edwards syndrome, and Down syndrome.

There is no way to prevent your baby from developing triploidy. No one is at a higher risk than others. Triploidy causes there to be three sets of chromosomes on every cell, causing there to be 69 chromosomes per cell instead of the normal 46. Any number of chromosomes that are more or less than the normal 46 lead to a chromosomal condition. This rare condition is life threatening, usually ending in a miscarriage or early infant death. Having one pregnancy affected by triploidy does not raise your risk of having another pregnancy with the same outcome.