What is confined placental mosaicism?

Confined placental mosaicism (CPM) is defined as the presence of a chromosomal abnormality in the placenta but not in the fetus.

What is trisomy 13 mosaicism?

Trisomy 13 mosaicism occurs when two cell lines, one with a normal complement of chromosomes and the other with an additional chromosome 13, are present in the same individual. We present two children with trisomy 13 mosaicism and summarize the literature in 47 published cases.

How does confined placental mosaicism occur?

Confined placental mosaicism occurs when the tissue of the placenta has an abnormal number of chromosomes, but the fetus itself has a normal number of chromosomes. In a majority of cases, confined placental mosaicism does not cause any health complications for either the pregnancy or the baby.

Can NIPT detect placental mosaicism?

Non-invasive prenatal testing (NIPT) has been widely used to screen for common aneuploidies since 2011. While NIPT is highly sensitive and specific, false positive results can occur. One important cause of false positive results is confined placental mosaicism (CPM).

Does trisomy 13 come from Mom or Dad?

Most cases of trisomy 13 are not inherited and result from random events during the formation of eggs and sperm in healthy parents. An error in cell division called nondisjunction results in an egg or sperm cell with an abnormal number of chromosomes .

How common is true fetal mosaicism?

With early fetal sampling made possible by chorionic villus sampling, it has become apparent that chromosomal mosaicism affecting the placenta occurs more frequently than previously considered (around 1–2% of samples).

When are trisomic cells only found in the placenta?

Confined placental mosaicism. CPM is diagnosed when some trisomic cells are detected on chorionic villus sampling and only normal cells are found on a subsequent prenatal test, such as amniocentesis or fetal blood sampling. In theory, CPM is when the trisomic cells are found only in the placenta.

Which is meiotic origin of trisomy in confined placental mosaicism?

“Meiotic origin of trisomy in confined placental mosaicism is correlated with presence of fetal uniparental disomy, high levels of trisomy in trophoblast, and increased risk of fetal intrauterine growth restriction”.

What are the three types of confined placental mosaicism?

There are three types of confined placental mosaicism depending on the cells involved at the time of the error: Type 1 CPM– The error occurs in a trophoblast cell, and thus only trophoblast cells are affected. This type of mosaicism is most often associated with normal pregnancy outcome.

Can a somatic error lead to confined trisomy?

Currently, there is no evidence that somatic errors, which lead to confined placental trisomy, are of any clinical consequence. Errors of meiotic origin are correlated with higher levels of trisomy in placental tissues and may be associated with adverse pregnancy outcome.

What is confined placental mosaicism? Confined placental mosaicism (CPM) is defined as the presence of a chromosomal abnormality in the placenta but not in the fetus. What is trisomy 13 mosaicism? Trisomy 13 mosaicism occurs when two cell lines, one with a normal complement of chromosomes and the other with an additional chromosome 13, are…