Tetraploidy
92,XXXX
Also known as: 92 XXXX, tetraploid
92,XXXX is tetraploidy: four complete chromosome sets instead of two, most often from a failed first division of the zygote. It is rarely compatible with ongoing pregnancy and is mainly seen in early pregnancy loss; in a report it must also be distinguished from a tetraploid artifact of cell culture.
Open in the interactive visualizer →
What the notation means
92- total chromosome count (normal is 46)
XXXX- sex chromosomes: four X
Clinical notes
Trisomy 21, Down syndrome
The most common autosomal trisomy compatible with life (~1/700 births). Three copies of chromosome 21. Features: characteristic facies, hypotonia, intellectual disability, ~50% congenital heart disease (AV canal), ↑ risk of AML/ALL and early Alzheimer disease. ~95% free trisomy (nondisjunction, ↑ with maternal age), ~4% Robertsonian translocation, ~1% mosaic.
Trisomy 18, Edwards syndrome
Three copies of chromosome 18. Clenched fists with overlapping fingers, rocker-bottom feet, micrognathia, congenital heart disease; most die in the first year.
Trisomy 13, Patau syndrome
Three copies of chromosome 13. Holoprosencephaly, cleft lip/palate, polydactyly, cutis aplasia; high early mortality.