Short answer · Medically reviewed summary · Last updated: 2026-05-08
Trisomy 13 Syndrome, also known as Patau syndrome, is a rare chromosomal disorder where an individual has three copies of chromosome 13 instead of the usual two, leading to severe physical and intellectual disabilities. This condition affects multiple organ systems and is typically identified shortly after birth due to distinct clinical features. What causes Trisomy 13 Syndrome? The underlying mechanism of Trisomy 13 Syndrome involves a chromosomal error during the formation of reproductive cells or early embryonic development.
What is Trisomy 13 Syndrome / Patau Syndrome
What is Trisomy 13 Syndrome / Patau Syndrome? Plain-language, medically reviewed definition plus the lived reality told by patients.
Trisomy 13 Syndrome, also known as Patau syndrome, is a rare chromosomal disorder where an individual has three copies of chromosome 13 instead of the usual two, leading to severe physical and intellectual disabilities. This condition affects multiple organ systems and is typically identified shortly after birth due to distinct clinical features.
What causes Trisomy 13 Syndrome?
The underlying mechanism of Trisomy 13 Syndrome involves a chromosomal error during the formation of reproductive cells or early embryonic development. In most cases, it is not an inherited condition but rather a random event during cell division. The presence of this extra genetic material disrupts normal fetal development, resulting in the complex medical challenges associated with Patau syndrome.
How does Patau syndrome affect the body?
Because chromosome 13 contains a vast amount of genetic information, Trisomy 13 Syndrome impacts almost every organ system. Common clinical presentations include:
- Severe intellectual disability and developmental delays.
- Structural heart defects, such as ventricular septal defects.
- Brain and spinal cord abnormalities, often including holoprosencephaly.
- Physical features such as cleft lip or palate, extra fingers or toes (polydactyly), and microcephaly.
- Weak muscle tone (hypotonia) and vision or hearing impairments.
How common is Trisomy 13 Syndrome?
Patau syndrome is estimated to occur in approximately 1 in 10,000 to 1 in 16,000 live births. While it can affect any infant, the incidence rate increases with maternal age. Because the condition is often associated with high rates of pregnancy loss or stillbirth, the true prevalence in the general population is difficult to determine. Currently, 31 individuals and families affected by Trisomy 13 Syndrome have joined the DiseaseMaps.org community to share their experiences and resources.
How is this condition different from other trisomies?
While Trisomy 13 Syndrome shares some features with other chromosomal disorders like Down syndrome (Trisomy 21) or Edwards syndrome (Trisomy 18), it is clinically distinct due to the specific combination of midline facial defects and profound neurological involvement. Unlike some other genetic conditions, the prognosis for Patau syndrome is generally more guarded, and management focuses on supportive care for the specific symptoms presented.
Next steps
- Consult with a clinical geneticist to discuss diagnostic testing and recurrence risks.
- Connect with the 31 members on DiseaseMaps.org to find peer support and shared experiences.
- Work with a multidisciplinary medical team, including cardiologists and neurologists, to create a personalized care plan.
Medical disclaimer: This information is for educational purposes only and should not replace professional medical advice, diagnosis, or treatment.
References
- NIH Genetic and Rare Diseases Information Center (GARD): Patau Syndrome.
- Orphanet: Trisomy 13.
- Online Mendelian Inheritance in Man (OMIM): Trisomy 13.
- Support Organization for Trisomy 18, 13, and Related Disorders (SOFT).
