Patau syndrome facts for kids

Patau Syndrome, also called Trisomy 13 or Trisomy D, is a rare chromosome problem. It happens when a baby has an extra copy of chromosome 13. Usually, humans have two copies of each chromosome. But with Patau Syndrome, there are three copies of chromosome 13 instead of two.

This extra chromosome usually happens by chance during the creation of a baby's cells. It can also happen because of a special change in chromosomes called Robertsonian translocation. The chance of this syndrome happening is a bit higher for mothers who have babies later in life. On average, this happens when mothers are around 31 years old.

Patau Syndrome is the rarest of three common chromosome conditions. The other two, Down syndrome and Edwards syndrome, happen more often. Patau Syndrome affects about 1 in 25,000 babies born alive.

What Are Chromosomes?

Chromosomes are tiny, thread-like structures inside our cells. They carry all the instructions that tell our bodies how to grow and work. These instructions are called genes. Humans normally have 46 chromosomes, arranged in 23 pairs. One pair determines if you are a boy or a girl. The other 22 pairs are numbered.

How Does an Extra Chromosome Happen?

Most of the time, Patau Syndrome happens because of a mistake during meiosis. Meiosis is the special process where our bodies make sperm and egg cells. Normally, when these cells are made, each one gets just one copy of each chromosome. But sometimes, a mistake happens, and an egg or sperm cell ends up with an extra chromosome 13. When this cell joins with a normal cell, the baby will have three copies of chromosome 13.

Robertsonian Translocation

Less often, Patau Syndrome can be caused by something called Robertsonian translocation. This is when a piece of chromosome 13 breaks off and attaches to another chromosome. The person might have the right amount of genetic material, but if they pass on this rearranged chromosome, their child could end up with an extra full copy of chromosome 13.

How Common Is Patau Syndrome?

Patau Syndrome is not very common. It affects about 1 in every 25,000 babies born alive. This makes it rarer than Down syndrome and Edwards syndrome, which are also conditions caused by extra chromosomes.

Images for kids

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  Chromosome 13, the affected chromosome in this disease.

See also

In Spanish: Síndrome de Patau para niños