Patau syndrome or trisomy 13 is a genetic disorder caused by anomalies in the 13th chromosome. It is characterized by severe developmental disabilities, and many fetuses with the condition do not even survive to be born. If a child does make it to birth with the condition, he or she may not live much beyond one year of age. In some cases, however, the syndrome is manageable, in which case the child may go on to live for many years, sometimes even under relatively normal circumstances.
The condition is a form of trisomy, meaning that there are three copies of the 13th chromosome, rather than the normal two. In most cases, the third copy is attached to the 13th chromosome. In other instances, however, a condition called translocation will occur, in which the extra 13th chromosome is actually attached to another chromosome. In less severe forms of Patau syndrome, the defect only expresses itself in some cells of the body, in a condition called mosaicism. These cases have the best prognosis.
The condition was first observed in 1656, when a Danish physician named Thomas Bartholin described it. Bartholin contributed a number of other achievements to science, including a description of the lymphatic system. In 1960, Dr. Klaus Patau linked the syndrome to a chromosomal abnormality, and trisomy 13 was named in his honor.
A surviving infant with trisomy 13 will have severe mental and developmental disabilities. Most infants have birth defects in the head and face, such as cleft palates, ocular damage, and unusually small heads. They may also have seriously compromised organs, such as defective hearts or abnormal genitalia. Extra fingers and toes are not uncommon with Patau syndrome, and the infant usually has poor motor skills.
The condition is not inherited, and is not the fault of either parent; chromosomal defects simply happen sometimes, and although scientists understand how they occur, they do not know why. However, some parents may carry a gene for translocation, in which case their children are at higher risk of chromosomal disorders. The risk also increases with maternal age. A case of Patau syndrome can be identified in prenatal testing, since the chromosomal disorder will be readily apparent. If prenatal testing reveals a chromosomal condition, parents should always retest before making any decision, as false positives do happen.
Treatment of Patau syndrome is focused on the myriad of problems which the infant may have. Surgical correction may be used for various physical defects, and children may also be placed on feeding tubes for nutrition. Respiratory therapy may be required, as many Patau children have trouble breathing. In severe cases where it is clear that the infant will die, analgesia is offered to make the child comfortable.