Term
|
Definition
Any agent that can produce a malformation or raise the population incidence of a malformation
Acts directly and transiently on developing embryonic tissue
|
|
|
Term
|
Definition
a pattern of multiple primary malformations or defects with a single underlying cause / etiologic agent causes multiple abnormalities in parallel
|
|
|
Term
Smith-Lemli-Opitz Syndrome |
|
Definition
•Example of overlap between a metabolic and developmental pathway (SHH signal transduction pathway)
•Cholesterol is involved in cleavage of sonic hedgehog (SHH), a secreted ligand, to N-SHH and potentially to the interaction of SHH with its receptor, Patched
|
|
|
Term
|
Definition
|
A group of abnormalities of unknown etiology and pathogenesis that is seen together more often than would be expected by chance.
ex. •VATERR Association
|
|
|
Term
|
Definition
•V – vertebral defects
•A – anal atresia +/- fistula
•T-E fistula with esophageal atresia
•R – radial dysplasia:
•thumb or radial hypoplasia
•preaxial polydactyly
•syndactyly
•R – renal anomaly
Cardiac defects, single umbilical artery, and prenatal growth deficiency are also nonrandom features
|
|
|
Term
|
Definition
|
localized anomaly that causes multiple pleitropic defects as secondary effects of the primary anomaly - a cascade of subsequent defects
ex •Robin sequence
–Heterogeneous
–Restricted mandibular growth causes posterior displacement of the tongue and interferes with palatal closure
–Results in U-shaped cleft palate
|
|
|
Term
|
Definition
•the genetic, biochemical, cellular, and physiological processes whereby a one-cell embryo gives rise to an entire organism
–Differentiation: process whereby one or more cells acquire a specific pattern of gene and protein expression characteristic of a particular cell type or tissue.
–Morphogenesis: process whereby changes in cell shape, adhesion, movement, proliferation, and/or death give rise to a three-dimensional structure.
–
|
|
|
Term
|
Definition
-between days 7-12 after fertilization
|
|
|
Term
|
Definition
- three primary germ layers arise from the epiblast
•Mosaic development –fate of a particular cell is specified independently of its environment (embryo can no longer easily compensate for damaged or lost cells)
•Organogenesis begins after gastrulation
(wks 4-8)
|
|
|
Term
Four major families of signaling molecules
|
|
Definition
Fibroblast Growth Factors (FGF)
- about 2 dozen exist and function in angiogenesis, mesoderm formation, axon extension
Hedgehog Proteins
– three homologs ; sonic, desert, indian – induce particular cell types and create boundaries between tissues
Wingless (Wnt) Family Proteins
-family of 15 cysteine-rich glycoproteins – functions: dorsal cells of somites to become muscle, polarity of limbs, GU system
Transforming Growth Factor B (TGF-B)
30 members – regulate formation of extracellular matrix between cells and cell division
|
|
|
Term
|
Definition
–Encode a class of transcription factors
–Determine regional identity along anterior-posterior axis
-Regional identity along axis of developing limb
|
|
|
Term
|
Definition
•9 human genes in the PAX family of transcription factors
•PAX3 - expressed in CNS during neural tube closure and later in the somites
•Neural crest cells –
–migrate throughout the embryo
–differentiate into many cell types – melanocytes, enteric and peripheral ganglia, Schwann cells …, and populate tissues including the facial bones and the cardiac outflow tracks
|
|
|
Term
Waardenberg syndrome Type I |
|
Definition
•Mutation of PAX3
–Heterozygosity for PAX3 loss-of-function mut results in a reduction of neural crest derivatives such as melanocytes in hair, eyes, and inner ear
•White forelock
•Pale colored eyes/ heterochromatic irides
•Sensorineural deafness
–Dystopia canthorum –
•outward displacement of the inner canthus
–Upper extremity defect –
•occasional
|
|
|
