Trisomy 21, better known as Down syndrome, is the most common chromosomal abnormality in humans, affecting almost 1 in 800 babies.¹² Down syndrome occurs when the baby inherits an extra genetic material from one parent, causing the physical features and developmental delays that characterize the disorder. It is not known why Down syndrome happens, and there is no way to prevent it. One known risk factor is maternal age—women who conceive over the age of 35 are at substantially increased risk. Women over the age of 40 are at even greater risk.

It is a common enough problem that the American College of Obstetrics and Gynecology recently recommended that all women should be offered screening for Down syndrome, regardless of maternal age. These special needs children may have serious health problems, e.g. congenital heart problems, in addition to developmental delays, so parents-to-be must know what lies ahead to prepare and make decisions that are right for them.

Screening for Down syndrome is performed using maternal serum to measure alpha-fetoprotein, estriol and human chorionic gonadotropin. Ultrasound, including nuchal translucency measurement is also used to look for physical characteristics of the fetus that are associated with the disorder. These tests are usually done between weeks 15 and 20 of gestation. Findings of these tests, combined with maternal age, are used to calculate risk before a definitive diagnosis is made. Current screening strategies for Down syndrome are limited by sensitivity (detection) and high false-positive rates.

To gain a definitive diagnosis of Down syndrome, invasive testing procedures such as amniocentesis, chorionic villus sampling or percutaneous umbilical blood sampling is required. While these procedures provide the opportunity for more sensitive and specific tests, women undergoing them should be at sufficient risk of having an affected pregnancy to warrant the possible adverse outcomes, the most significant of which is miscarriage.

ProteoGenix envisions improving screening and subsequent diagnosis of Down syndrome through an improved non-invasive, multi-analyte maternal serum screening test. The company has identified novel protein biomarkers in maternal serum that may provide the basis for new tests for improved Down syndrome screening. The significance of this discovery has been acknowledged by the Society for Maternal-Fetal Medicine at the 2005 annual meeting with the presentation of the Society’s Best Research Award.

ProteoGenix has been awarded Phase-I and Phase-II SBIR grants by the National Institutes of Health to investigate its approach to Down syndrome screening. With approximately 2.6 million commercial tests annually in the United States, the potential market for a more accurate diagnostic methodology is well established.

Amniocentesis - a surgical procedure is performed to collect amniotic fluid using a needle inserted into the uterus through the abdominal wall

Chorionic villus sampling - removal of a small piece of placental tissue early in pregnancy for genetic testing

Percutaneous umbilical cord blood sampling - a surgical procedure to collect blood from the umbilical cord for testing