Human birth defects

Question 1

Malformation

Answer 1

A morphological defect of an organ, part of an organ, or larger region of the body that results from an intrinsically abnormal developmental process that is abnormal from the beginning (ie, chromosomal abnormality)

Question 2

Disruption

Answer 2

A morphological defect that results from the breakdown of, or interference with an originally normal developmental process (ie, teratogens)

Question 3

Deformation

Answer 3

an abnormality that results from mechanical forces that mold a part of the fetus over a prolonged period (ie. oligohydramnios)

Question 4

syndrome

Answer 4

a group of anomalies that have a specific common cause

Question 5

Causes of human birth defects

Answer 5

Most are unknown (50-60%), genetic factors, teratogens, multifactorial factors

Question 6

Susceptibility to teratogens depends on

Answer 6

genotype of the conceptus, developmental stage at time of exposure, and dose and duration of exposure

Question 7

when is the most sensitive period of embryonic development?

Answer 7

3rd to 8th week

Question 8

Rubella

Answer 8

can cause congenital rubella syndrome in the fetus of an infected pregnant woman. Causes a triad of malformations: cataracts, cardiac defect (PDA), and deafness

Question 9

Cytomegalovirus

Answer 9

Most commonly transmitted virus to fetuses during pregnancy and can cause hearing loss, vision loss, and mental retardation

Question 10

Toxoplasma gondii-protozoan (toxoplasmosis)

Answer 10

Causes microcephaly, microphthalmia, hydrocephaly

Question 11

Congenital zika syndrome

Answer 11

severe microcephaly with partially collapsed skull, decreased brain tissue, damage to the back of the eye, joints with limited range of motion (club foot), too much muscle tone

Question 12

Tranquilizers (lithium, diazepam, and thalidomide)

Answer 12

limb deformities

Question 13

Ethanol

Answer 13

abnormal facial features, congenital heart defects, and mental retardation

Question 14

Facial features seen in FASD

Answer 14

short palpebral fissures, flat midface, short nose, indistinct philtrum, thin upper lip, epicanthal folds, low nasal bridge, minor ear anomalies, micrognathia

Question 15

Cigarette smoke

Answer 15

IUGR due to restricted uterine blood vessels via nicotine, low birth weight, increased risk for preterm delivery, impaired growth of cerebral cortex neuron, associated with ADHD and learning disabilities

Question 16

Retinoic acid (vit A)

Answer 16

high risk for spontaneous abortion, birth defects

Question 17

anticoagulants (warfarin)

Answer 17

chondrodysplasia, microcephaly

Question 18

Heroin, methadone

Answer 18

central nervous dysfunction and low birth weight

Question 19

chemotherapeutic agents

Answer 19

highly teratogenic because they inhibit mitosis in rapidly dividing cells. Use of anti-tumor chemicals results in intrauterine death of most embryos and severe malformations in those that survive

Question 20

anticonvulsants (valporic acid, diphenylhydantoin, trimethadione)

Answer 20

facial defects, cleft palate, heart defects, neural tube defects, urogenital and skeletal abnormalities

Question 21

Hormones

Answer 21

cause masculinization of female external genitalia

Question 22

cocaine

Answer 22

spontaneous abortion, prematurity, microcephaly, and neurobehavioral disturbances

Question 23

hyperthermia

Answer 23

maternal heatstroke damages proteins

Question 24

ionizing radiation

Answer 24

strong mutagen which causes chromosomal structural damage leading to cell death. CNS, palate, and skeletal system are especially sensitive