Patau syndrome is the least common and most severe of the viable autosomal trisomies. It is a genetic disorder in which a person has three copies of genetic material from chromosome 13, instead of the usual two copies.
Trisomy 13 occurs in about 1 out of every 10,000 newborns. Most cases are not inherited. Instead, the events that lead to Trisomy 13 occur in either the sperm or the egg that forms the fetus.
A significant number of cases that are trisomic for chromosome 13 end in spontaneous abortion, foetal demise, or stillbirth. More than 80% of children with trisomy 13 die in the first month. Only one in 20 children survive longer than 6 months.
- Extra fingers or toes (polydactyly). Clenched hands with outer fingers on top of the inner fingers.
- Deformed feet, known as rocker-bottom feet
- Severe mental deficiency. Small head, failure of the brain to divide into halves during gestation.
- Facial defects such as small eyes, absent or malformed nose, cleft lip and/or cleft palate
- Heart defects in 80% of individuals.
- Kidney defects
- Hernias: umbilical hernia, inguinal hernia.
- Undescended testicle.