Syndronue: Case Study and Review

Karyotyping by invasive prenatal testing such as amniocentesis or chorionic villi sampling is the only definitive method of determining Down syndrome. However, both methods are associated with procedure-related risks. The combination of two noninvasive tools, the maternal serum triple screen and the ultra-sound examination, provides a way of identi-fying fetuses at higher risk for Down syn-drome. Ultrasound markers are sonographic findings that may exist as structural malfor-mations or normal variants that are more prevalent in Down syndrome. Depending on the particular marker, either a single marker or a cluster may indicate an increased risk of an affected fetus. Sonographic markers include duodenal atresia, cardiac detects, brachycephaly, mild ventriculomegaly, flat-tened facial profile, thickened nuchal skin fold, fetal hydrops, hyperechoic bowel, chor-oid plexus cysts, pyelectasis, shortened ex-tremities, echogenic intracardiac foci, greater iliac wing angle, and specific findings in the fetal hand and foot. Key words: Down syndrome, prenatal diag-nosis, trisomy 21, ultrasound Trisomy 21 or Down syndrome is the most fre-quently occurring chromosomal abnormality found at birth, with the overall incidence of 1 in 660 live births. ’ Statistically, the risk of having an affected child increases with maternal age. The in-cidence of Down syndrome at maternal age 30 years is 1 in 1000, whereas at maternal age 40 years, the risk is 9 in 1000.2 However, because most births occur in younger women, 80 % of neonates with Down syndrome are born to women younger than 35 years of age. Clinical features of Down syndrome include both physical and mental developmental delays, with a mean IQ of approximately 50.3 Characteris-tic physical findings include flattened occiput and brachycephaly, along with a flattened bridge of the nose. The hands are short and wide with a single palmar crease. There may be hypoplasia of the mid-phalanx of the fifth digit with clinodactyly. The fee