III: Birth Defects Flashcards
_____ approach: study cellular interactions and differentiation over time
system
______: similar defects resulting from predominantly genetic mutations or predominantly environmental exposures
phenocopies
Define VACTERL defects.
Vertebral, anal atresia, cardiac, tracheoesophageal atresia, renal, limb
Describe the screening results in Down Syndrome.
low MSaFP, low uE3, high hCG, high InhA, low PAPP-A
Describe the screening results in Trisomy 13/Patau Syndrome.
low PAPP-A
Describe the screening results in Trisomy 18/Edwards Syndrome?
low MSaFP, low uE3, low hCG, low PAPP-A.
Describe the testing for CF.
CFTR DNA test for mother, then partner, then invasive fetal testing
Describe the testing for hemoglobinopathies.
Hemoglobin electrophoresis (Beta chain), DNA testing (Alpha chain)
Developmental fields may involve the following four parameters.
Time, location, gene expression, interacting processes
How is gestational age determined during the first trimester?
Crown-rump length
How is gestational age estimated during the second and third trimesters?
Biparietal diameter, Abdominal circumference, femur length
Name 4 major classifications of birth defects
Malformation, Disruption, Dysplasia, Deformation
Name 5 indications for invasive diagnostic testing
Maternal age over 35, previous affected child, positive aneuploidy, parental chromosome rearrangements, abnormal ultrasound findings
Name two means of invasive prenatal diagnosis.
Chorionic villus sampling, Amniocentesis
Name two phenocopies for abnormal truncus arteriosus development.
22q11 deletion/DiGeorge Syndrome, isoretinoin
Name two theories regarding the development of birth defects.
Hierarchical pathways, Developmental fields
What produces alpha-fetoprotein?
Fetal liver
What screening result may be suggestive of a neural tube defect?
high MSaFP
When can free fetal DNA be obtained from maternal serum?
10 weeks gestation
When is amniocentesis performed?
14-20 weeks
When is chorionic villus sampling performed?
9.5-12.5 weeks
When is estimation of gestational age most accurate?
Early in the pregnancy
Which defects can be screened for with the Nuchal Translucency Test?
Down Syndrome, Trisomy 18/Edwards
Which diagnosis? 50% of children die in the first month of life
Trisomy 13/Patau Syndrome
Which diagnosis? Holoprosencephaly, cleft lip/palate, polydactyly, cardiac defects
Trisomy 13/Patau Syndrome
Which diagnosis? Low-set ears, micrognathia, rocker-bottom feet
Trisomy 18/Edwards Syndrome
Which diagnosis? Mean survivial of months
Trisomy 18/Edwards Syndrome
Which diagnosis? Microcephaly, overlapping fingers, shield chest
Trisomy 18/Edwards Syndrome
Which invasive diagnostic method carries a greater risk of fetal loss?
Chorionic villus sampling
Which parameter best differentiates Trisomy 18 and Trisomy 21?
hCG (high in Trisomy 21/low in Trisomy 18)
Which population should be screened for Tay Sachs disease?
Ashkenazi Jew
