Patterns of Fetal Anomaly (lesson 29) Flashcards
What is an analyte?
Any substance measured in a laboratory
What is Aneuploidy?
An abnormal number of chromosomes
What is a Haploid?
Normal number of chromosomes in a cell
What is Mitosis?
Division of a cell resulting in the normal haploid number
What is Meiosis?
Division of a cell in which there is a reudction, by half, in the normal haploid number of chromosomes
What is pre-eclampsia?
Triad of: HYPERTENSION, FLUID RETENTION (EDEMA), AND PROTEINURIA after 20 wks of gestation
What is a quadruple screen?
Testing for maternal levels of AFP, unconjugated estriol (uE3), hCG, and inhibin A
What does a triple screen test for?
Maternal levels of AFP, uE4, and hCG
What is a syndrome?
A pattern of multiple anomalies seen in numerous individuals that is not related to a single factor or pathology
What is an association?
A pattern of multiple anomalies seen in numerous individuals that is not related to a single factor or pathology
What is a sequence?
A pattern of multiple anomalies that results from an initial single anomaly.
What can be the result of a malformation, deformation, or disruption? (sequence, association, or syndrome)
A sequence
What are the 4 categories of anomalies? MDDD
Malformation, deformation, disruption, dysplasia
What is heteroploidy?
Changes of number of chromosomes present in the cells - numeric anomalies
What is Euploidy?
The condition in which there are integral multiples of the haploid number (23) of chromosomes (ex; Triploidy)
What is Aneuploidy?
A departure from the euploid number of chromosomes (having an extra chromosome in a set, triploidy, or missing a chromosome of a set, monosomy)
When does the chromosomal nondisjunction occur during?
Meiosis
What is more common: structural abnormalities of the chromosomes or numerical abnormalities?
Numerical abnormalities
What can cause breakage of a chromosome?
Drugs, radiation, viruses, or chemical agents
DRVC
What are two examples of environmental teratogens?
Fetal rubella syndrome and fetal alcohol syndrome
What are the risk factors for chromosomal abnormalities? (4)
Maternal age, previous pregnancy with chromosomal abnormality, history of pregnancy loss, advanced paternal age
In the first trimester, what are the 3 measurements done for screening for Trisomy 21?
Increase in hCG
Decrease in PAPP-A
Increased NT
What are the 4 biochemical markers used for prenatal screening in the second trimester?
MSAFP, hCG, unconjugated estriol (uE3), and inhibin A
What is one of the two syncytiotrophoblastic hormones used in prenatal screening?
uE3
What organs synthesize uE3?
Adrenal gland and liver
What deconjugates uE3?
Placenta
In Trisomy 21, a quadruple screen will have which values elevated and which values low?
Inhibin A (elevated)
hCG (elevated)
AFP (low)
uE3 (low)
What is the classic sonographic feature in Beckwith-Weidemann Syndrome?
Macroglossia
What is a Triploidy?
The presence of a complete extra set of chromosomes
In first trimester, what lab values are affected in Triploidy?
Elevated MSAFP and hCG, low PAPP-A
In second trimester, what lab values are affected in Triploidy?
hCG low, low uE3, low (or normal) AFP
90% of triplodies are due to… ?
two sperms fertilizing one egg or from an extra chromosome set from the mother
What is diandry?
Two sperms fertilizing one egg
What is digyny?
An extra chromosome set from the mother
In Triploidy, what happens if the mother contributes the extra chromosomes?
A fetus with asymmetric IUGR and a small placenta
In Triploidy, what happens if the father contributes the extra chromosomes?
A fetus with symmetric IUGR and a large (hydropic) placenta
What is a mosaic trisomy 13?
A person with the extra chromosome in some of their cells
