The aim of such testing is to reveal an early state of genetic disorders such as trisomy 21 (Down syndrome), trisomy 18 (Edward syndrome), trisomy 13
(Patau syndrome), and monosomy X (Turner syndrome).
The condition, also known as Trisomy 13
, doesn't run in families in most cases.
The positive predictive value in this cohort was 95.2% for trisomy 21, 93.5% for trisomy 18, 77.9% for trisomy 13
, and 86.7% for monosomy X.
They were offered CVS (Chorionic Villus Sampling) to check if their child had either Trisomy 13
, Trisomy 18 or Trisomy 21.
A 28 year old, G5P2AB2 woman was admitted to our clinic (Shahidan Mobini Hospital, Sabzevar University of Medical Sciences, Sabzevar, Khorasan Razavi, Iran) for perinatologist counseling at 15 weeks of gestation due to remarkable decrease of her first trimester double biochemical markers and therefore in the high-risk range for trisomy 13
And it has been found more frequently in infants with Patau syndrome (trisomy 13
with a Robertsonian translocation) (Aziz, 1980) and Edward syndrome (trisomy 18) at autopsy (Bersu & Ramirez-Castro, 1977).
(3) An unbalanced chromosome of the gamete, which has the chromosome with the 13/15 translocation plus the normal 13; this would cause the fertilized embryo to present a trisomy 13
. (4) The unbalanced chromosomal complement with normal 13 and absence of a 15.
The rare condition often affects the brain, making the survival of these animals with mutations difficult. The deformity can either develop from toxins and environmental pollution or due to Trisomy 13
, which is associated with harsh intellectual disability and certain physical aberrations in parts of the body.
While chromosomal abnormalities are identified in 24%-45% of HPE cases, trisomy 13
is most frequently reported (2, 3).
For example, a sample positive for trisomy 13
might have a Z-score of 8 for chromosome 13, but the Z-scores for chromosome 21 and 18 would be between -3.0 and 2.99.