Patau syndrome
Overview
Patau syndrome or Trisomy 13 is a rare and very severe chromosome disorder leading to mental retardation and physical defects. It is so severe that many babies die soon after birth.
Trisomy 13 occurs when extra DNA from chromosome 13 appears in some or all of the body's cells.
Symptoms
- Cleft palate
- Omphalocele
- Patent ductus arteriosus
- Dextrocardia
- Malnutrition
Causes
Trisomy 13 occurs when extra DNA from chromosome 13 appears in some or all of the body's cells.
- Trisomy 13 -- the presence of an extra (third) chromosome 13 in all of the cells.
- Trisomy 13 mosaicism -- the presence of an extra chromosome 13 in some of the cells.
- Partial trisomy -- the presence of a part of an extra chromosome 13 in the cells.
The extra material interferes with normal development.
Trisomy 13 occurs in about 1 out of every 10,000 newborns. Most cases are not passed down through families (inherited). Instead, the events that lead to trisomy 13 occur in either the sperm or the egg that forms the fetus.
Diagnosis
The infant may have a single umbilical artery at birth. There are often signs of congenital heart disease, such as:
- Abnormal placement of the heart toward the right side of the chest instead of the left
- Atrial septal defect
- Patent ductus arteriosus
- Ventricular septal defect
Gastrointestinal x-rays or ultrasound may show rotation of the internal organs.
MRI or CT scans of the head may reveal a problem with the structure of the brain. The problem is called holoprosencephaly. It is the joining together of the two sides of the brain.
Chromosome studies show trisomy 13, trisomy 13 mosaicism, or partial trisomy.
Prognosis
Prognosis of Patau syndrome: Poor. Low survival rates and mental retardation in those that do.