Patau syndrome, also known as trisomy 13 and trisomy D, is a chromosomal abnormality, a syndrome in which a patient has an additional chromosome 13 due to a nondisjunction of chromosomes during meiosis.
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.
Patau syndrome is the least common and most severe of the viable autosomal trisomies.
Trisomy 13 occurs in about 1 out of every 10,000 newborns.
Median survival is fewer than 3 days, with only one in 20 children surviving longer than 6 months.
The sex ratio at birth is slightly skewed toward females, presumably because of decreased survival among males.
Newborns with Patau syndrome typically present in the neonatal period with low Apgar scores and may have the following conditions:
- Cleft lip
- Cleft palate
- Polydactyly (postaxial)
- Rocker-bottom feet