Rare Triploidy: A Serious Chromosomal Abnormality in Pregnancy
Triploidy, a rare chromosomal abnormality, affects 1-3% of conceptions. It occurs when a fetus has an extra set of chromosomes, totaling 69 instead of the usual 46. This condition has no increased prevalence in older mothers or hereditary cases.
Triploidy can be caused by abnormal fertilization, such as two sperm fertilizing one egg or a diploid sperm fertilizing a normal egg. This can lead to two types: digynic, where the mother provides the extra chromosomes, often resulting in late-term pregnancies; and diandric, where the father provides the extra chromosomes, typically leading to early miscarriages.
Pregnant women carrying fetuses with triploidy may experience preeclampsia, characterized by albuminuria, edema, and hypertension. Unfortunately, fetuses with triploidy rarely survive to birth and have multiple severe birth defects if they do. Infants born with full triploidy usually do not survive more than a few days. However, children born with mosaic triploidy, where some cells have the extra set and others do not, often survive for many years.
Unlike triploidy, trisomy affects specific pairs of chromosomes (13, 18, and 21).
Triploidy is a serious condition with significant implications for both the fetus and the mother. While it is not hereditary or more common in older mothers, it can lead to severe complications and often does not result in live births. Further research is needed to understand and address the challenges posed by this chromosomal abnormality.
