Deformations, Disruptions, & Teratogens Flashcards
What is pleiotropy?
In many cases, a single defective gene is sufficient to cause the multiple manifestations of the genetic syndrome, which often involve multiple organ systems. This phenomenon is called pleiotropy.
The SHH gene is involved in…
limb and CNS development
What is Tracher Collins syndrome?
- craniofacial anomalies
- dysplastic ears
- deafness
- autosomal dominant
- causative gene = TCOF1, which codes for a protein called Treacle
good example of pleiotropy
The gene mutation which results in the Smith-Lemli-Opitz syndrome is an example of a
A. continguous gene syndrome
B. fetal deformation
C. fetal disruption
D. malformation sequence
E. pleiotropic gene mutation
E. pleiotropic gene mutation
What is Smith-Lemli-Opitz syndrome?
Genetic defects in the gene for 7-dehydrocholesterol reductase (7-DHCR), which is required for the last step of cholesterol synthesis, result in the Smith-Lemli-Opitz syndrome, which is characterized by multiple congenital anomalies including
* craniofacial anomaly
* syndactyly
* genital hypoplasia
* mental deficiency
* CNS malformation
What is Pierre Robin Sequence?
It is a rare congenital birth defect characterized by an underdeveloped jaw, backward displacement of the tongue and upper airway obstruction. Cleft palate is also commonly present in children with Pierre Robin sequence.
so swallowing so jaw doesn’t develop, tongue thrusted upwards, palate doesn’t close because of tongue
Which of the following is not considered a deformation in an infant born to a mother who has a large uterine fibroid during pregnancy?
A. congenital hip dislocation
B. joint contracture
C. Pierre Robin sequence
D. Renal agenesis
E. Troticollis with facial asymmetry
D. Renal agenesis
Deformation is caused by the mechanical constraint or pressure on the developing fetus, resulting in distortion of a normal developmental process. The most common cause of deformation is due to space constraint within the uterus
Fetal exposure to valproate is most often assocaited with which one of the following birth defects?
A. Dextrocardia
B. Esophageal atresia
C. Intestinal malrotation
D. Neural tube defect
E. Renal anomaly
D. Neural tube defect
Which one of the following teratogenic exposures is most often associated with major limb anomalies in the fetus?
A. Alcohol
B. Hyperthermia
C. Maternal PKU
D. Maternal rubella infection
E. Thalidomide
E. Thalidomide
The most common teratogenic cause of mental retardation in the US is the prenatal exposure of the fetus to:
A. alcohol
B. cytomegalovirus (CMV)
C. rubella
D. valproic acid
E. varicella
A. alcohol
Which one of the following teratogens is most likely to result in an increased likelihood of neural tube defects in the exposed fetus?
A. Cigarette smoking
B. Ciprofloxacin
C. Isotretinoin
D. Thalidomide
E. Valproic acid
E. Valproic acid
Which ones of the following is not a well documented teratogen?
A. Alcohol
B. Aspirin
C. Retinoic acid
D. Reubella
E. Valproate
B. Aspirin
d
Deformations vs disruptions of fetal development
Deformations are due to mechanical/ space constraints
Disruptions are interruptions of normal develpment and can be caused by things like amniotic bands
The risk for which one of the following teratogenic conditions cannot be assessed by blood tests during pregnancy?
A. fetal alcohol effect
B. infant of a diabetic mother
C. maternal PKU effect
A. fetal alcohol effect
infant born with
* bilateral microtia
* micrognathia
* down-slanting palpebral fissures
* lateral labial clefts
A. Angelman syndrome
B. Noonan syndrome
C. Tracher-Collins syndrome
D. Trisomy 13
E. Zellweger syndrome
microtia = small unformed ear
C. Tracher-Collins syndrome
