What does Sage screen for
Autosomal aneuploidies
Trisomies occur when three, instead of the usual two, copies of a chromosome are present in each cell. When the number of chromosomes differs from the usual two this is referred to as an aneuploidy. The Sage™ prenatal screen test estimates the risk of a fetus having Down’s syndrome (Trisomy 21), Edwards’ syndrome (Trisomy 18) and Patau’s syndrome (Trisomy 13). Edwards’ and Patau’s syndrome are much rarer than Down’s but are very serious and many affected babies are not born alive or do not survive for long after birth. Upon request, the Sage™ prenatal screen may also estimate the risk of other autosomal trisomies. The detection rate for Trisomy 21, 18 and 13 is greater than 99%
Sex chromosome aneuploidies
In addition to the autosomal trisomies, the Sage™ prenatal screen may also report on sex chromosomal aneuploidies. Everyone also has a set of sex chromosomes in each of their cells. Women have two ‘X’ chromosomes (XX) while men have one ‘X’ and one ‘Y’ chromosome (XY). The impact of sex chromosome aneuploidy is generally much milder than aneuploidy of chromosomes 13, 18, and 21. The following aneuploidies can be screened for
Monosomy X – Turner syndrome
XXX – Triple X syndrome
XXY – Kleinfelter syndrome
XYY – Jacob’s syndrome
Microdeletions
Upon request, testing for select microdeletion syndromes is available. A microdeletion syndrome is caused by the absence of a small portion of genetic material in the chromosome. They vary greatly in severity, with the symptoms of microdeletions ranging from minimal developmental delays to severe anomalies e.g. cardiac defects, neurological malformations, etc
Fetal sex determination
Upon request, and in regions where fetal sex determination is permitted, the fetal sex can be determined with 99.9% accuracy