Congenital anomalies Flashcards
Define a congenital malformation.
A structural defect present at birth
What are the factors that lead to congenital malformations?
Hereditary (genetic/chromosomal factors)
Environmental
(Interaction of genetic and environmental factors
Heart defects, Cataracts, Glaucoma (blindness due to pressure in eyeballs), and Deafness are characteristic abnormalities of which environmental agent?
Rubella virus/German measles
What possible abnormalities can be brought about by exposure of developing embryo/fetus to HIV?
Microcephaly (small head)
Growth retardation
How do infectious agents cause malformations?
Many of them are pyrogenic (they cause fever/hyperthermia); the hyperthermia causes malformations
Give 3 examples of numerical chromosomal abnormalities.
Down’s Syndrome/Trisomy 21
Turner syndrome/Missing one X chromosome in females
Klinefelter syndrome/Having 2 X chromosomes in males
Give 3 examples of structural chromosomal abnormalities.
Cri-du-chat syndrome/ Deletion of genetic material on Chromosome 5
Angelman syndrome/ Deletion/Absence of UBE3A gene on maternal chromosome
Prader-Willi syndrome/Deletion of a gene on paternal chromosome
What are the phenotypes of Down’s syndrome?
Only 1 palmar transverse crease Lazy eyes Bent pinky finger Thick skin on palms, soles, and back of neck Intellectual disability
State the symptoms of Angelman’s syndrome.
Abnormally small head Widely spaced teeth, mouth, and nose Frequent laughter and smiling Hyperactive Crossed eyes
How does Turner syndrome present?
Lack of menstruation Late development Short stature/height Obesity Wide-spaced nipples Congenital heart defects Recurrent ear infections Webbed neck
What is the phenotype of Cri-Du-Chat syndrome?
Cat-like cry when infant
High pitched voice
Severe mental retardation
What proportion of conceptions end in spontaneous abortion?
50%
What is a major cause that accounts for 50% of the spontaneous abortions?
Major chromosomal abnormalities
A pregnant patient comes with severe hemorrhaging in the second month. She may have experienced _________.
an ectopic/extrauterine pregancy
What is a primary ovarian pregnancy?
Development of blastocyst in ovary wall
Where in the abdominal cavity does the embryo normally attach?
Douglas’s pouch/ Peritoneal Lining of Retouterine cavity
Define abortion
The premature exit of the products of conception (the fetus, fetal membranes, and placenta) from the uterus
Define anencephaly
Congenital defect in which part of the brain and the bones around it do not form; caused by neural tube failing to close at the cranial neuropore around day 24
Define microcephaly
A smaller head than usual caused by incomplete development of the brain
What are the causes of microcephaly?
Malnutrition
Lack of oxygen to brain
Chromosomal abnormalities ex: Down’s syndrome, Angelman’s syndrome
What are increased levels of AFP (alpha-fetoprotein) related to?
Neural tube defects
Gut abnormalities
When can AFP (alpha-fetoprotein) maternal screening test be done?
When embryo is around 14 days old
What classification does an abnormality fall into if it occurs during organogenesis?
Malformation
Differentiate malformation, deformation, and disruption.
Malformation - occurs in embryonic phase during formation of structures
Deformation - occurs in late fetal phases, a result of mechanical force applied to normally developing or already developed structures
Disruption - can occur at any time, a result of destructive force (ex; virus or mechanical force) on an already-formed and developing structure that is normal
