Patau syndrome (also known as trisomy 13) is considered the 3 commonest autosomal trisomy.
Patau syndrome along with Down syndrome (trisomy 21) and Edward syndrome (trisomy 18) are the only three trisomies to be compatible with extrauterine life. However, few infants live more than a few days.
The estimated incidence is approximately 1:6,000. There may be an increased incidence with advanced maternal age.
Described features are protean and include
- congenital heart disease: 50-80%
- central nervous system/head and neck abnormalities: 70%
- spinal anomalies
- intrauterine growth restriction (IUGR): tends to be early
- abnormal facies: 90%, strong marker
- skeletal abnormalities
- abdominal wall abnormalities
- genitourinary anomalies
Three forms are known
- free trisomy 13: classical form
- translocation trisomy 13
- mosaic trisomy 13
Many of the individual clinical features listed above may be seen on ultrasound. Other general features include:
- abnormal liquor volumes: either polyhydramnios (more common) or oligohydramnios
- evidence of IUGR: especially early
- increased nuchal thickness
- evidence of hydrops fetalis
- echogenic bowel
- echogenic chorda tendinae
Treatment and prognosis
The syndrome carries a poor prognosis with most individuals not surviving beyond in utero or soon after birth. Management is mainly supportive.
Clinically, individuals with Meckel-Gruber syndrome may carry some features similar to that of trisomy 13.