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Trisomy 13

(Patau Syndrome; Trisomy D)

By

Nina N. Powell-Hamilton

, MD, Sidney Kimmel Medical College at Thomas Jefferson University

Reviewed/Revised Dec 2021 | Modified Sep 2022
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Topic Resources

Trisomy 13 is caused by an extra chromosome 13 and causes abnormal forebrain, midface, and eye development; severe intellectual disability; heart defects; and small birth size. Diagnosis is with cytogenetic testing. Treatment is supportive.

Trisomy 13 occurs in about 1/10,000 live births; about 80% of cases are complete trisomy 13. Advanced maternal age increases the likelihood, and the extra chromosome is usually maternally derived.

Infants tend to be small for gestational age Small-for-Gestational-Age (SGA) Infant Infants whose weight is < the 10th percentile for gestational age are classified as small for gestational age. Complications include perinatal asphyxia, meconium aspiration, polycythemia... read more . Midline anomalies are common and include holoprosencephaly Holoprosencephaly Cerebral hemispheres may be large, small, or asymmetric; the gyri may be absent, unusually large, or multiple and small. In addition to the grossly visible malformations, microscopic sections... read more Holoprosencephaly (failure of the forebrain to divide properly), facial anomalies such as cleft lip and cleft palate Cleft Lip and Cleft Palate An oral-facial cleft is a birth defect in which the lip, the roof of the mouth, or both do not close in the midline and remain open, creating a cleft lip and/or cleft palate. These defects are... read more Cleft Lip and Cleft Palate , microphthalmia Microphthalmia Eyes can be absent, deformed, or incompletely developed at birth, often in conjunction with other congenital abnormalities and syndromes. (See also Introduction to Congenital Craniofacial and... read more Microphthalmia , colobomas Coloboma Eyes can be absent, deformed, or incompletely developed at birth, often in conjunction with other congenital abnormalities and syndromes. (See also Introduction to Congenital Craniofacial and... read more Coloboma (fissures) of the iris, and retinal dysplasia. Supraorbital ridges are shallow, and palpebral fissures usually are slanted. The ears are abnormally shaped and usually low-set. Hearing loss is common. Scalp defects and dermal sinuses are also common. Loose folds of skin often are present over the back of the neck.

Diagnosis of Trisomy 13

  • Cytogenetic testing by karyotyping, fluorescent in situ hybridization (FISH) analysis, and/or chromosomal microarray analysis

Confirmatory testing is offered in cases suspected based on NIPS. Management decisions, including termination of pregnancy, should not be made based on NIPS testing alone. See also The American College of Obstetricians and Gynecologists Committee on Practice Bulletins–Obstetrics, Committee of Genetics, and the Society for Maternal–Fetal Medicine 2020 practice bulletin regarding cell-free fetal DNA testing.

Treatment of Trisomy 13

  • Supportive care

Most patients (80%) are so severely affected that they die before age 1 month; < 10% survive longer than 1 year. Support for the family is critical.

More Information

The following is an English-language resource that may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

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