genetic counseling Flashcards
dysmorphology/morphogenesis
abnormal physical dev.
teratology`
study of environmental causes of congenital anomalies
what can malformation be due to?
chromosome abnormalities, single gene disorders, teratogens, multifactorial, pregnancies complications, unknown
the cause of ____ of congenital defects is unknown or multifactorial
2/3
a known genetic component of congenital defects is in about _____% of cases
30%
environmental causes for congenital anomalies are _______
infrequent
malformation?
primary defect of an organ or body part from an abnormal developmental process
malformation examples
spina bifida, polydactyly, cleft lip
dysplasia?
primary defect involving abnormal organization of cells into tissues
dysplasia examples?
port wein stains, hip dysplasia, pointy teeth
sequence
primary defect with secondary structural changes; basically one thing goes wrong which causes a cascade of other events to occur
sequence example
potter sequence
what is potter sequence
less amniotic fluid got to the fetus from renal disease/obstruction which caused clubbed feet, pulmonary hypoplasia, and cranial anomalies
syndrome?
pattern of multiple primary malformations with a single gene causing it; malformation are UNRELATED!!
syndrome example
down syndrome
deformation?
changes in the form, shape, or position of a normally formed body part from mechanical forces; this is a secondary alteration
deformation example
plagiocephaly, clubfoot
disruption?
defect of an organ, part of an organ, or larger region of the body because something interfered with development
disruption example
amniotic band
most important question to ask when evaluating a child with a congenital malformation
is the defect isolated or part of a syndrome
teratogens?
agents that cause birth defects when present in the environment of a developing fetus
these act directly and transiently on developing embryonic tissue
teratogens
are individual thresholds for teratogen effects predictible
NO
organs and parts of an embryo are most sensitive to teratogenic agents during periods of __________
rapid differentiation
3 principles to consider when there is a teratogenic exposure
critical period, dosage of drug/chemical, genotype of embryo
critical period?
when cell division, differentiation, and morphogenesis is at its peak