What is Trisomy 13 Syndrome?

wiseGEEK Writer

Patau or trisomy 13 syndrome was first identified in the 17th century and is a relatively rare but extremely serious chromosomal disorder. In this condition, the growing fetus develops with three copies of the 13th chromosome instead of having just two, which is the normal arrangement. This creates a variety of serious defects and problems and in many cases the condition is so serious that a child does not survive to birth or does not survive the first year of life. The majority of children with trisomy 13 syndrome do not live, but some can and may survive to later adulthood.

Trisomy 13 is believed to be similar to Down syndrome in that aging can create problems with chromosomes.
Trisomy 13 is believed to be similar to Down syndrome in that aging can create problems with chromosomes.

It may be important to understand that trisomy 13 syndrome is not usually an inherited condition. It’s linked to chromosomal errors in the reproductive cells (sperm and egg). These may be more common with aging, particularly in women. There are other disorders like Down syndrome where aging creates problems with chromosomes, and it appears that Patau is like this. If a reproductive cell contains an additional 13th chromosome, then this may become part of the fetus.

Patau's syndrome results from an extra copy of chromosome 13.
Patau's syndrome results from an extra copy of chromosome 13.

Sometimes the 13th chromosome isn’t expressed in every cell of the growing fetus’ body. This is called mosaicism. It may result in somewhat milder expression of trisomy 13 syndrome and a slightly improved prognosis.

In addition to risk for early mortality, those with this condition may have a number of congenital defects or health problems. In particular, heart defects are common and may require surgery in early life in order to sustain life. Other possible expressions of this syndrome are cleft palate, defects of the hands, malformations of the eyes, reduced head and jaw size, and, in males, testicles that have not descended. Babies with trisomy 13 syndrome may be severely mentally retarded, have poor muscle control and tone, have significant issues with feeding, and may possibly have seizures.

Not all symptoms are present in all children with trisomy 13 syndrome, which means treatment of this condition very much depends on individual cases. Treatment could include surgery to address life-threatening defects, support for feeding with possibly feeding tubes, treatment of seizures and other measures. A treatment plan should include finding support for parents, as this condition can be an extremely difficult one and parents may need anything from instruction on how to care for a high need infant at home to grief counseling.

In a natural conception, there is no way to prevent trisomy 13 syndrome. The condition can be identified through testing like amniocentesis, giving people the option to terminate a pregnancy if a fetus has this chromosomal abnormality. As difficult as it is, some parents also make the choice to not intervene medically if a child is born with this condition. These are weighty decisions best made with the help of counselors and other support, and people who have lost a child with Patau through any means may be best helped by seeking grief counseling and therapy.

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