Repro/GU First Aid

Question 1

Important genes in embryogenesis

Answer 1

Sonic hedgehog gene- produced at base of limbs in zone of polarizing activity, involved in patterning along anterior-posterior axis, involved in CNS development, mutation can cause holoprosencephaly
Wnt-7 gene- produced at apical ectodermal ridge, necessary for proper organization along dorsal-ventral axis
FGF- produced at apical ectodermal ridge, stimulates mitosis of underlying mesoderm, providing for lengthening of limbs
Homeobox- involved in segmental organization of embryo in a craniocaudal direction, a mutation produces appendages in wrong locations

Question 2

Teratogens

Answer 2

ACEI- renal damage
Alkylating agents- absence of digits, other anomalies
Aminogylcosides- CN VIII toxicity
Carbamazepine- neural tube defects, craniofacial defects, fingernail hypoplasia, developmental delay, IUGR
Diethylstilbestrol- vaginal clear cell adenocarcinoma, congenital Mullerian anomalies
Folate antagonists- neural tube defects
Lithium- Ebstein anomaly (atrialized right ventricle)
Methimazole- aplasia cutis congenita
Phenytoin- fetal hydrantoin snydrome: microcephaly, dysmorphic craniofacial features, hypoplastic nails and distal phalanges, cardiac defects, IUGR, ID
Tetracyclines- discolored teeth
Thalidomide- limb defects
Valproate- inhibition of maternal folate absorption leading to NTD
Warfarin- bone deformities, fetal hemorrhage, abortion, ophthalmologic abnormalities