Congenital and Genetic Diseases

Question 0

Congenital deformations

Answer 0

result from mechanicl forces (small uterus, large fetus, compression of the fetus - oligohydramnios) (i.e., positions of feet)

Question 1

Congenital malformations

Answer 1

result from intrinsically abnormal developmental process (i.e., spina bifida, congenital heart disease, Polydactylyl)

Question 2

Congenital disruptions

Answer 2

result from breakdown of a normal developmental process (limb amputation due to amniotic band)

Question 3

What is a syndrome?

Answer 3

A characteristic association of several anomalies.

Question 4

What is Potter Syndrome?

Answer 4

Combination of both malformations and deformations. Typically abnormal kidney development leading to decreased amniotic fluid and compression of fetus. This can cause pulmonary hypoplasia and death due to respiratory insufficiency.

Question 5

What are teratogens?

Answer 5

Agents that produce congenital malformations.

Question 6

Congenital infections with teratogenic effects include:

Answer 6

Germal measles, cytomegalovirus, varicella zoster (chicken pox)

Question 7

Drugs/chemicals with teratogenic effects include:

Answer 7

Thalidomide/Alcohol

Question 8

Materal disorders that cause teratogenic effects include:

Answer 8

Diabete mellitus

Question 9

Ionizing radiation that cause teratogenic effects include:

Answer 9

Increased incidence of microcephaly and mental retardation.

Question 10

What is the mechanism of congenital rubella (german measles)?

Answer 10

If the mother gets rubella w/I the 1st trimester, fetus will be infected and will inappopriately divide; end result is growth retardation, cataracts, deafness, and congenital heart diesease.

Question 11

Wha is the mechanism of thalidomide?

Answer 11

Used to relief of nausea during pregnancy, it interferes with proper lib growth during the 3rd and 5th week post-conception. End result is phocomelia (seal limbs).

Question 12

What is the effect of alcohol as a teratogen?

Answer 12

Fetal-alcohol syndrome (most common cause of mental retardation in the Western world): Pre/post-natal growth retardation, mental retardation, joint anomalies, heart deficitis, abnormal facscies.

Question 13

Why is diabetes dangerous for fetuses?

Answer 13

Risk for malformation is 6%, can be upto 20%. Insulin-dependent is most dangeorus. Sympoms include: malformations in kidney, heart, and brain.

Question 14

What are the different types of chromosomal disorders?

Answer 14

Numerical, sex, and structural

Question 15

Autosomal chromosome numerical abnormalities

Answer 15

Autosomal include Trisomy 21 and Down Syndrome; More dangerous than sex (abnormal fascies, palmar creases, congenital diseases, duodenal stenosis or atresia, and mental retardation). Significant with advanced maternal age.

Question 16

Sex chromosome numerical abnormalities

Answer 16

Sex include Turner Syndrome (XO) and Klinefelter Syndrome (XXY); result in loss of 2nd sexual characteristics and infertility.

Question 17

Structural chromosomal abnormalities

Answer 17

Deletion of parts of chromosomes; Cri-du-chat (partial deletion of ch5 - causes cat-like cry in infancy, small head and facial abnormalities).

Question 18

Three types of single-gene disorders

Answer 18

Autosomal dominant, autosomal recessive, X-linked recessive

Question 19

Characteristics and examples of autosomal dominant disorders:

Answer 19

(1) at least one parent has the disease, (2) 50% risk to children, and (3) both sexes are equally affected. Example include marfan syndrome and familiar hypercholesterolemia.

Question 20

What is marfan syndrome?

Answer 20

On chromosome 5, error in connective tissue. Long limbs, dislocation of lens and eye and dilation of aorta.

Question 21

What is familiar hypercholesterolemia?

Answer 21

On chromosome 19, very common and leading cause of coronary heart disease. Defect in LDL receptor, thus elevated cholesterol in plasma and deposition of cholesterol in arteries. Fatal in childhood (1/1000000).

Question 22

Characteristics and examples of autosomal recessive disorders:

Answer 22

(1) both parents are normal, but carriers, (2) 25% risk to children, (3) both sexes are equally affected; Diseases include CF and phenylketonuria (PKU).

Question 23

What is CF (cystic fibrosis)?

Answer 23

On ch7, most common auto-rec disease in caucasian children (1/1600); carriers are 1/20 incidence. Respiratory tree mucous is abnormal causing repeated infection, in addition to intestinal inabsorption due to lack of pancreatic secretion..

Question 24

What is phenylketonuria (PKU)?

Answer 24

Disruption in phenylalanine oxidase (phenylalanine to tyrosine); damages developing brain in early childhood and severe mental retardation. Treated with low-phenylalanine diet.

Question 25

Characteristics and examples of X-linked recessive disorders:

Answer 25

(1) mother is a carrier, (2) 50% affected sons, (3) 50% carrier daughters; example is hemophilia A

Question 26

What is hemophilia A?

Answer 26

In chromosome X, absent normal blood clotting factors; prolonged bleeding, especially in joints. Caused by deficiency in coagulaiton factor VII.

Question 27

What are multifactorial disorders?

Answer 27

Due to the effect of multiple genes and interaction between genetic and environmental factors. They run in families.

Question 28

What are some examples of multifactorial disorders?

Answer 28

Cleft plate, congenital heart disease, spina bifida.