Which are the causes of Edwards syndrome?

TL;DR: Edwards syndrome, also known as Trisomy 18, is caused by the presence of an extra copy of chromosome 18 in the body’s cells, which disrupts normal development. This chromosomal abnormality is almost always a random event during the formation of reproductive cells and is not caused by anything the parents did or did not do.

What causes Edwards syndrome at the genetic level?

At the most fundamental level, Edwards syndrome is a chromosomal condition. Humans typically have 46 chromosomes in each cell, arranged in 23 pairs. In individuals with Edwards syndrome, there is a third copy of chromosome 18 instead of the usual pair. This "extra" genetic material acts like an instructional manual that has been printed twice; the cells receive too many instructions, which leads to the complex developmental challenges associated with the condition. There are three primary ways this can occur:

• Full Trisomy 18: The most common form, where every cell in the body contains an extra chromosome 18. This accounts for approximately 95% of cases.


• Translocation: A piece of chromosome 18 attaches to another chromosome during the formation of reproductive cells or very early in fetal development.


• Mosaic Trisomy 18: Only some of the body’s cells have the extra chromosome, while others have the typical pair. This often results in a milder presentation of the syndrome.

Is Edwards syndrome an inherited condition?

It is important to clarify that Edwards syndrome is rarely inherited. In the vast majority of cases, the error occurs randomly as a "nondisjunction" event—a biological accident where chromosomes fail to separate correctly during the production of egg or sperm cells. Because this is a stochastic (random) event, parents who have had a child with Edwards syndrome are not generally at a higher risk of having another child with the condition, though a clinical geneticist should always review individual family history.

Are there known environmental triggers or risk factors?

There are no known environmental, dietary, or behavioral factors that cause Edwards syndrome. It is not caused by anything the parents did before or during pregnancy. The only statistically significant risk factor identified in clinical literature is advanced maternal age. As a woman ages, the likelihood of errors occurring during the division of egg cells increases, which slightly raises the probability of conceiving a child with a chromosomal trisomy, including Edwards syndrome. However, it is vital to emphasize that this is a biological trend, not a reflection of parental actions.

What is current research revealing about the etiology?

While the chromosomal cause of Edwards syndrome is well-understood, medical researchers are currently focusing on "genotype-phenotype correlation." This means scientists are studying exactly how specific genes located on chromosome 18 contribute to the wide range of physical and developmental symptoms observed in the 108 members of the DiseaseMaps.org community and others worldwide. By mapping which regions of the extra chromosome are responsible for specific heart, kidney, or growth issues, researchers hope to improve personalized care and early intervention strategies for families facing a diagnosis of Edwards syndrome.

Next steps

• Consult with a board-certified clinical geneticist to review specific karyotype results.


• Connect with the DiseaseMaps.org community to share experiences and find support from others navigating this diagnosis.


• Speak with a genetic counselor to understand the implications for future family planning.


• Reach out to specialized pediatric centers that offer multidisciplinary care for infants with complex chromosomal conditions.

Medical disclaimer: This content is for informational purposes only and does not constitute medical advice, diagnosis, or treatment; always seek the advice of your physician or other qualified health provider with any questions regarding a medical condition.

References

• NIH Genetic and Rare Diseases (GARD) Information Center: Trisomy 18.


• Orphanet: Edwards syndrome (ORPHA:885).


• Online Mendelian Inheritance in Man (OMIM): Trisomy 18; #176600.


• The Trisomy 18 Foundation: Educational resources and family support.