Nursing 209

N209: Reproductive Health Study Guide

Most severe NTD

Anencephaly •

• Neural tube does not close completely; missing major parts of brain, skull, and scalp • Usually only live for a few hours after birth • Occurs in 1:4859 births in the U.S. • Affects girls three times more than boys Chromosomal defect involving an extra chromosome 21 • Can be either a whole extra chromosome (in 95% of cases) or a translocation onto another chromosome • The most common genetic abnormality in the U.S. affecting 1:700 babies/year • Risks: Maternal age over 35 (although majority are born to women below age 35 because of the number of births in that group) • Screening tests: o Nuchal translucency via ultrasound o NIPT: To evaluate circulating DNA in maternal blood o Diagnostic tests: Evaluates actual chromosomal changes o Chorionic villus sampling (CVS) o Amniocentesis o Percutaneous umbilical sampling (PUBS) • Health problems: o Heart defects (50%) o Eye problems (up to 60%, usually congenital cataracts and glaucoma) o Ear infections (50-70%) o Hearing loss (up to 75%) o Sleep apnea/obstructive (50-75%) o Prone to Hirschsprung disease and endocrine disorders (hypothyroidism and diabetes) • Types o Trisomy 21: 95% of cases; three copies of chromosome 21 instead of two o Translocation Down Syndrome: 3% of cases; extra chromosome 21 attached to a different chromosome o Mosaic Down Syndrome: 2% of Down Syndrome; some cells have three copies of chromosome 21, but others cells are normal (often have fewer features of Down Syndrome due to presence of normal cells)

6.6 Chromosomal Defects Down Syndrome •

©2018

Achieve

Page 91

of 109