Special Needs Children: Trisomy 13 (Patau Syndrome)
Trisomy 13 syndrome, also known as Patau syndrome, is a chromosomal disorder like Down syndrome that occurs in 1 out of 5,000 live births.
Every cell in our body, except for the sex cells, contains 46 chromosomes. We inherit 23 chromosomes from each of our parents. Infants with trisomy syndrome have an extra (third) number 13 chromosome in either all the cells of their body, or in a small number of cells.
Approximately 80 percent of infants with the syndrome will have full trisomy, that is they will have an extra number 13 chromosome in all the cells of their body. These special needs infants often don't reach their first birthday because of multiple abnormalities, including brain defects that cause apnea, seizures, deafness, and eye problems.
The remaining 20 percent of infants with trisomy will get the syndrome from a rearrangement of genetic information or translocation between chromosomes. These infants often have a better chance of surviving infancy.
What Causes Trisomy 13?
The cause of trisomy 13 is largely unknown. But a strong association exists between trisomy 13 and increased maternal age. Also, the risk of trisomy 13 increases with each pregnancy.
Characteristics and Symptoms of Trisomy 13
The characteristics of the trisomy 13 are numerous. The common characteristics, which are present at birth, include the following:
- microcephaly (small head size)
- microphthalmia (small eyes, most likely with defects)
- cleft lip
- cleft palate
- low-set ears
- extra fingers or toes
Other symptoms of trisomy 13 syndrome include:
- mental retardation
- scalp defects
- close set eyes
- skeletal abnormalities
Infants with trisomy 13 will also experience gastroesophageal reflux and feeding problems. About 80 percent of infants affected by trisomy 13 will also have congenital heart abnormalities. While heart abnormalities are not a serious health concern during infancy, irregularities can include:
- Ventricular septal defect: An opening between the lower chambers of the heart, which makes it difficult for the heart to pump blood
- Patent ductus arteriosus: Causes a channel that usually closes near the time of birth to remain open
- Atrial septal defect: An opening between the upper chambers of the heart that slows down the flow of oxygen-rich blood to body tissues
- Dextrocardia: The positioning of the heart on the right side of the chest
Because of the common heart abnormalities present, young children with trisomy 13 require regular cardiac evaluation, as well as vision and hearing tests.
Expectations of Survival
The median age of survival for infants with full trisomy syndrome is 2.5 days. One out of 20 infants survive for longer than 6 months. However, some children do survive into their teens.
Diagnosis and Prevention of Trisomy Syndrome
Trisomy syndrome can be diagnosed during the second trimester of pregnancy with the use of amniocentesis. Amniocentesis tests for chromosomal irregularities in the amniotic fluid.
Parents of infants with partial trisomy, that is trisomy caused by translocation, can use genetic testing and counseling in order to help prevent having trisomy syndrome in future pregnancies.
Because trisomy 13 manifests itself in various symptoms and characteristics, no standard treatment or cure exists. But routine visits to evaluate cardiac, vision, hearing, and cognition in children with trisomy 13 is necessary.
Parents of children with trisomy 13 should also think about joining support groups to connect with other parents who have or had children with trisomy 13, and to learn about the joys and challenges a child with trisomy can bring.
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