Development and Teratogenesis Flashcards
Teratogens
Come from the outside
4 classes of teratogens and examples
Maternal illness (PKU, diabetes) INfectious agents (TORCH) Physical agents (radiation or heat exposure) Drugs (thalidomide, antiepileptic drugs)
Response ot teratogens
Highly individual and could have to do with a lot of different things such as route, timing, dose
All or nothing theory
In enough cells die, spontaneous abortion
If only a few cells die, others can compensate
Significant exposure to teratogens during days ________ post-conception may result in cell death
10-14
Day 27
Closure of neural tube
Day 30
Appearance of limb buds
Weeks 4 and 5
Branchial arches, clefts, piuches, and optic vesicle
Week 5 to 7
HEart and kidneys
Week 8
Mature limb architecture
Weeks 7 to 10
Internal and external genitalia
Week 10
Rotation into abdominal cavity
Teratogenesis occurs _______
After fertilization
Toxic mutagenesis
Exposure prior to conception causing mutations
Toxic mutagenesis females vs. males
Females - DNA replication occurs during oogenesis years before ovulation
Males - continous spermatogensis makes males more susceptible
Infectious agents mechanisms
Usually direct invasion of fetal tissues…lead to inflammation and cell death
Infectious teratogenic agents
TORCH, varicella, and parvovirus B19
TORCH infection
Toxoplasmosis, rubella, cytomegalovirus, herpes, and syphilis
Maternal illnesses mech
Diffusion of teratogenic metabolite or antibody across the placenta
Insulin-dependent diabetes mellitus birth defect
2-3 fold increase…hyperglycema can cause diabetic embryopathy resulting in major birth defects and spon abortions…glucose acts as teratogen
PKU (in short)
Inability ot make tyrosin from Phe…microceph, intellectual, cong heart disease
Causes phenylalanine embryopathy
Treat using low Phe diet
Androgen-producing tumors effect
In adrenals or ovaries…can lead to viriliation of female fetuses
MG can lead to
Transient neonatal myasthenia
Maternal illness antibody diseases
Transient neonatal myasthenia and systemic lupus erythematosus
Maternal antibodies can
Cross placenta into the fetus
Systemic lupus erythematosus can lead to
Fetal heart block
Elevation in maternal core temperature can lead to
Neural tube defects
ACE inhibitors can cause
Miscarriage
Oligohydramnios
Renal failure
Hypotension
Antiepileptics can cause
Cardiovascular
Orofacial clefts
Neural tube malformations
GU defects
Teratogenic meds
Thalidomide Retinoic Acid Statins ACE inhibitors Antiepileptics
FASD includes
FAS, pFAS, Neurobehavrioal disorder with prenatal alcohol exposure (ND-PAE)
Alcohol can affect
CNS abnormalities, growth retardation, facial dysmorphism and abnormalities
First trimester alcohol
Facial anomalies/structural anomalies/including brain size
Second trimester alcohol
Increased spontaneous abortion
Third trimester - alcohol
Predominantly effects weight, length, and brain growth
How are FAS and pFAS different than ND-PAE
No facial dysmorphology or growth retardation
Clinical features at birth - alcohol
Facial dysmorphism
Facial dysmorphism of FAS
Short palpebral fissure
Thin vermillion border
Smooth philtrum
Structural CNS impairment - alcohol
Decreased head size
Neurologic CNS impairment - alcohol
Hard - reflexes, tone, cranial nerve defects
Soft - poor coordination or balance
FAS diagnosis
3 facial dysmorphology, growth retardation AND CNS involvement…does NOT require prenatal alc exposure confirmation
pFAS diagnosis
Confirmation of alc exposure…2/3 facial dysmorphologies, growth retardation, OR CNS involvement
NDPAE diagnosis
Requires confirmation
Imapaired cog function, self-regulation, and adaptive function
