Aneuploid: Causes, Types, Symptoms, Risks, Treatment and Mutations in Pregnancy

It is an individual that has a mutation in its chromosomal number, either due to the absence or the extra of one of the copies.

In general, all the people who have their correct chromosome endowment are called or known as euploid, while the individuals who present a variation are indicated that they suffer from an aneuploidy.

Aneuploidy is nothing more than the chromosomal mutation that an individual can present at birth.

The most palpable and common case to explain this condition is Down syndrome . Where a trisomy occurs right on chromosome number 21, that is, there are three copies of the same chromosome.

Aneuploidy can also occur in cancer cells.

Causes of Aneuploid Mutation

There are several factors that can influence the chromosomal malformation just in the period of its formation when the unborn is in the process of gestation.

However, the two main factors that cause or are attributed to this chromosomal mutation are the following:

  • When there is a delay in the meiosis of the chromosome, thus generating that it is not found during anaphase, which consists of the chromosome separation stage.
  • The second factor, and it is usually the more common of the two, is when adequate meiotic segregation does not occur during mitosis. That is, there is no normal chromosome disjunction in the body and therefore the chromosome mutation or loss occurs.


For the complete development of the human being, there must be a composition of 46 chromosomal pairs created, formed and perfectly organized.

When this process is generated correctly and the pairs are created properly it is said that an eida cell was created.

But when the process was not formed in the correct way and the opposite occurs, that is, when the 46 chromosomal pairs were not formed or there are more than necessary, it is when it is called an Aneuploid cell.

Then according to the chromosome type that was seen or is affected, it is called, for example, as follows:

  • Autosomal aneuploidy.
  • Aneuploidy of the sex chromosomes.

When the mutation comes from the lack of one or a chromosomal pair and the extra chromosome, aneuploidy is called as follows:

  • Monosomy: it is when a single non-sexual chromosome is needed in the composition of the 46 pairs.
  • Nulisomy: occurs when only one pair of homologous chromosomes is missing.
  • Disomy: This mutation occurs when two extra chromosomes are generated.
  • Trisomy: it is one of the most common cases and occurs when there is a single extra chromosome, that is, 47 of the total chromosome are total.
  • Tetrasomy: this case occurs when two more chromosomes develop in the chain, giving a total of 48.
  • Pentasomy: occurs when the woman has three X chromosomes in her chain.

Symptoms and risks of Aneuploidy

Some studies have hypothesized that the risks of generating a genetic mutation in the composition of chromosomes occurs when the woman is at an advanced and risky age to begin the process of gestation with an unborn child.

When the woman is between 45 years of age and older, she is more prone to the unborn having abnormalities in her development.

This is due to the increase or decrease of the chromosomes found in the egg cells because they are older and more likely to lose their qualities or composition.

Therefore, the first risk factor for the fetus is to develop a genetic disease that puts its life at risk or, failing that, to be born with certain physical or mental deficiencies.

In the case of embryos that fail to complete or develop their sex chromosomes correctly, they tend to die before the completion of the gestation cycle or at birth.

On the other hand, trisomies type aneuploidy, the extra chromosomal copy allows them to survive in the development process but will be born with physical or mental defects or abnormalities.

Treatment for Aneploid Mutation

Depending on the genetic mutation, if the case requires it, a treatment will be indicated.

They are generally based on giving a better quality of life to patients who suffer from a congenital defect or disease product of the type of aneploid they suffer.

Aneuploid in pregnancy

Thanks to technological and scientific advances, genetic mutations can be detected in the first weeks of pregnancy through DNA studies in maternal blood.

If the study were positive in a case of trisomy, education and psychological support are essential for the family nucleus of the future baby at birth, to know the behavior and life patterns that they must assume to give them a quality of life.