PATAU SYNDROME (TRISOMY 13)

Patau syndrome or trisomy 13 is a genetic condition in which cells in the body have 3 copies of chromosome 13 instead of 2. The condition arises when mistakes occur during cell division and fertilization when the egg or the sperm carries an additional copy of chromosome 13 and passes it on to the embryo.

Also called

• Trisomy 13
• Bartholin-Patau syndrome
• Complete trisomy 13 syndrome
• Patau's syndrome
• Trisomy 13 syndrome

Symptoms

Main symptoms include:

• Bilateral cleft lip and palate
• Various eye defects: microophthalmia (small eyes), anophthalmia (missing eye or eyes), coloboma (missing tissue in eye)
• Microcephaly (small head)
• Hexadactyly (sixth finger or toe)
• Ear dysplasia
• Scalp defects
• Omphalocele (abdominal organs develop outside of the body due to a defect in the abdominal wall)
• Heart defects
• Cystic kidneys
• Central nervous system anomalies such as arhinecephaly or holoprosencephaly.
• Impaired psychomotor development

Frequency

The average incidence of Patau syndrome is estimated to be 1:5,000 newborns.

Cause

Patau syndrome is caused by an extra chromosome 13. In 75% of cases, the extra chromosome is in all cells of the body (called free trisomy 13), while mosaic trisomy (extra chromosome in some cells) is seen in 5%, and an unbalanced translocation (part of an extra chromosome in cells) is seen in 20%.

Inheritance

Patau syndrome is not usually inherited.

Screening and diagnosis

Prenatal detection is possible through ultrasound, serum marker screening, and non-invasive prenatal testing (NIPT). NIPT has the highest detection accuracy and can be performed from the 10th week of pregnancy. Prenatal diagnosis is integral in trisomy 13 management, as it reduces postnatal diagnostic delays, and facilitates earlier and better decision-making by parents and physicians. Diagnosis is confirmed by karyotying after birth.

Treatment

Treatment is dependent on the symptoms.

References

Vendola et al. 2010, Am J Med Genet 152A:360 / Wyllie et al. 1994, Arch Dis Child 71:343 / Baty et al. 1994, Am J Med Genet 49:189 / Fujinaga et al. 1990, Teratology 41:233 / Hassold et al. 1987, J Med Genet 24:725

MedlinePlus [Internet]. Bethesda (MD): National Library of Medicine (US); [updated 2020 Jun 24]. Trisomy 13; updated 09 Sept. 2021; Available from: https://medlineplus.gov/genetics/condition/trisomy-13/. Accessed 24 Feb. 2025.