Congenital anomalies

Question 1

Define congenital anomalies.

Answer 1

structural or functional anomalies (e.g. metabolic
disorders) that occur during intrauterine life and can be identified prenatally, at birth or later in
life eg hearing loss

Question 2

Describe the affects of teratogenic agents at different stages of gestation.

Answer 2

• During the first 2 weeks of development, teratogenic agents usually kill the embryo or have no effect.
• During the organogenesis period (3rd – 8th weeks), teratogenic agents disrupt development and may cause major congenital anomalies.
• During the fetal period (9th week – 9th month) teratogens may produce morphological and
  functional abnormalities, particularly of the brain and eyes.

Question 3

Define malformations

Answer 3

morphologic defect of a part of an organ that has resulted from abnormal developmental process eg congenital heart disease, cleft lip and/or cleft palate.

Question 4

Define disruption

Answer 4

results in morphological change of the already formed structure due to exposure to destructive process. e.g.: vascular accidents leading to intestinal atresia, amniotic band disruption.

Question 5

Define deformation.

Answer 5

due to mechanical forces that affect a part of the fetus over a long period. Ex: talipes equinovarus deformity(club-foot)

Question 6

List causes of chromosomal abnormalities.

Answer 6

• late maternal age at the time of pregnancy (leads to chromosomal non-disjunction),-
• radiation (causes chromosome deletions, translocations or breaks)
• viruses as German measles,
• autoimmune diseases,
• some chemical agents as anti-mitotic drugs

Question 7

Explain how radiation may lead to congenital abnormalities.

Answer 7

onizing radiation kills rapidly proliferating cells, producing any type of birth defect
depending upon dose and stage of development. Ex. Atomic bomb on Hiroshima and Nagasaki.
* Exposure of the pregnant woman to a large dose of x- ray can lead to microcephaly, spina bifida or
cleft palate

Question 8

Outline Down syndrome, Edward syndrome and Patau syndrome.

Answer 8

All are aneuploidy
Trisomy
Down syndrome- 21
ES: 18
PS: 13

Question 9

Outline turner syndrome.

Answer 9

female missing an X chromosome
45, X

Question 10

Outline Klinefelter syndrome.

Answer 10

47, XXY male with an extra X

Question 11

Outline environmental factors that contribute to congenital abnormalities.

Answer 11

Infectious agents: a number of viruses
Radiation: Xrays
Chemicals: dangerous drugs
Hormones:

Question 12

What are the non-invasive prenatal diagnosis techniques?

Answer 12

• Maternal serum screen : Alpha feto protein (AFP) - Neural tube defects (NTD)
• Triple test - Down syndrome
• Ultrasound Structural defects in many organs as CNS, heart,kidney, and limbs

Question 13

What are the invasive prenatal diagnosis techniques?

Answer 13

• Amniocentesis Chromosomal and metabolic abnormalities
• Chorionic villus sampling as amniocentesis.

Question 14

Describe a congenital rubella infection.

Answer 14

. It causes cataract, glaucoma, heart defects and deafness

Question 15

Describe a CMV infection.

Answer 15

The infection is often fatal and if not meningoencephalitis produce mental
retardation.

Question 16

What happens in a syphilis infection?

Answer 16

leads to congenital deafness and mental retardation.