Trisomy13 (a.k.a. Patau Syndrome)


  • results from having three copies of genetic material from chromosome 13 versus the usual two copies in each cell

  • Only a percentage of cells may be affected
  • Discovered by Klaus Patau in 1960
  • Occurs in 1 in 16,000 newborns


  • most cases are not inherited (result from random errors during the formation of egg and sperm in healthy parents)
  • Some cases are inherited due to balanced translocations


  • Aminocentesis-chromosomal studies of amniotic cells


  • cleft lip/palate
  • close-set eyes--eyes may actually fuse into one
  • extra fingers/toes
  • hole,split, or cleft in the iris
  • severe mental retardation
  • small eyes, head, lower jaw
  • congential heart disease
Newborn affected by extra toes and fingers, close-set eyes, and a smaller head.
Newborn affected with cleft palate and lip


  • chromosomal studies


  • varies from child to child and depends on specific symptoms


  • more than 80% of children die within the first year

Support Organization for Trisomy 13 and Related Disorders

Some newborns do survive.

1. Who discovered Trisomy 13?
2. What primarily causes some cases to be inherited?
3. What prenatal-test can determine whether or not the child has this disorder?
4. Name three characteristics of this disorder.
5. What is the prognosis?