Trisomy 16

Trisomy 16 is a chromosomal condition in which cells carry three copies of chromosome 16 instead of two. Complete trisomy 16 is generally incompatible with survival to birth, while mosaic forms can survive.

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Nondisjunction: Nondisjunction is the failure of chromosomes or chromatids to separate properly during cell division. It can create an egg, sperm, or early embryonic cell with an extra chromosome 16.
Complete trisomy 16: Complete trisomy 16 is the presence of three copies of chromosome 16 in essentially all cells. This form is generally incompatible with survival to birth.
Prenatal diagnosis: Prenatal diagnosis identifies genetic or structural conditions in a fetus before birth. Trisomy 16 findings can arise during screening or diagnostic testing in pregnancy.
Spontaneous abortion: Spontaneous abortion is the loss of a pregnancy before the fetus can survive outside the uterus. Complete trisomy 16 is a common chromosomal finding in early pregnancy losses.
Mosaicism: Mosaicism is the presence of genetically distinct cell populations within one individual. A mixture of trisomic and non-trisomic cells distinguishes many surviving cases from complete trisomy 16.
Mosaic trisomy 16: Mosaic trisomy 16 is the presence of both trisomic and non-trisomic cell lines involving chromosome 16. Survival is possible, with outcomes varying according to tissue distribution and other factors.
Noninvasive prenatal testing: Noninvasive prenatal testing analyzes cell-free DNA in a pregnant person's blood to screen for fetal chromosome conditions. Its chromosome signals largely originate in the placenta, so trisomy 16 may not represent fetal cells.
Placental insufficiency: Placental insufficiency occurs when the placenta cannot adequately support fetal oxygen or nutrient needs. Trisomic placental cells can compromise placental function and fetal growth.
Trisomy rescue: Trisomy rescue is the loss of one chromosome from a trisomic cell during early development. It can produce a cell line with two copies after conception began with three.
Placental trisomy 16: Placental trisomy 16 is the presence of cells with an extra chromosome 16 in placental tissue. Placental involvement can affect pregnancy even when fetal testing finds no trisomic cells.