Alternate Names: Patau syndrome

Causes and Risks: Trisomy 13 (which occurs in about 1 out of every 20,000 live births) is seen at about half the rate of trisomy 18. It is a syndrome with multiple abnormalities, many of which are not compatible with more than a few months of life. Almost half of the affected infants do not survive beyond the first month and about three quarters die within six months.

Trisomy 13 is associated with multiple abnormalities, including severe mental defects and defects of the brain that lead to seizures (hypsarrhythmia), apnea, deafness and ocular abnormalities. The eyes are small with defects in the iris (coloboma). Most infants have a cleft lip and cleft palate and low-set ears. Congenital heart disease is present in approximately 80% of affected infants. Hernias and genital abnormalities are common.

Prevention: Trisomy 13 can be diagnosed prenatally by amniocentesis with chromosome studies of the amniotic cells. Trisomy 13 mosaicism and partial trisomy 13 also occur. Parents of infants with translocation type trisomy 13 should also have translocation studies.

Symptoms:

• mental retardation, severe
• seizures
• small head (microcephaly)
• scalp defects (absent skin)
• small eyes (microphthalmia)
• cleft lip
• cleft palate
• eyes close set (hypotelorism); eyes may actually fuse together into one
• iris defects (coloboma)
• pinna abnormalities and low set ears
• Simian crease
• extra digits (polydactyly)
• hernias: umbilical hernia, inguinal hernia
• cryptorchidism, male
• hypotonia
• micrognathia
• motormental retardation
• skeletal (limb) abnormalities

Signs and Tests: The infant may have a single umbilical artery at birth. There are often signs of congenital heart disease:

• ventricular septal defect (VSD)
• atrial septal defect (ASD)
• patent ductus arteriosus (PDA)
• abnormal placement of the heart (dextroversion--the heart is placed toward the right side of the chest instead of the left)

Treatment: Because of the severity of congenital defects, life-sustaining procedures are generally not attempted.

Prognosis: Extremely short survival time is expected.

Complications: Complications begin almost immediately. They include breathing difficulty or lack of breathing (apnea), deafness, vision problems, feeding problems, seizures, heart failure, and others.

Call for an appointment with your health care provider if you have had a child with Trisomy 13 and you plan to have another child.