Developmental Diseases

Question 1

What are the two main categories of factors that contribute to developmental diseases

Answer 1

-Genetic factors
-Environmental factors
-Can be combo of the two

Question 2

What factor is the most likely cause of congenital developmental disease

Answer 2

Genetic

Question 3

3 major categories of genetic factors

Answer 3

-Chromosomal abnormalities
-Single gene abnormalities
-Multifactor abnormalities

Question 4

Chromosomal abnormalities

Answer 4

Most common one associated with severe morphological defects. Usually due to changes in number or structures of chromosomes

Question 5

Monosomy

Answer 5

One less chromosome

Question 6

Trisomy

Answer 6

Extra chromosome

Question 7

Result of chromosome abnormalities

Answer 7

Often cause embryonic death, abortion, or still births

Question 8

Single gene abnormalities

Answer 8

Changes in single protein. Depending on that protein can have little or no effect or sever effects

Question 9

Major categories of genes affected in single gene abnormalities

Answer 9

-Structural proteins
-Receptor proteins
-Enzymes
-Regulatory proteins

Question 10

Inheritance of single gene abnormalities

Answer 10

-Autosomal
-Sex linked

Question 11

Multifactorial

Answer 11

Disease due to two or more gene abnormalities

Question 12

Syndactyly

Answer 12

Fusion of two functional digits “mulefoot” Can happen in humans. Common in bovines (autosomal recessive in holsteins)

Question 13

Where is the bovine syndactyly defect found

Answer 13

On bovine chromosome 15 containing Lrp4 gene. 2 aa subsitution

Question 14

LRP4 gene

Answer 14

Negative regulator of the Wnt-B-catenin pathway causing abnormal limb development and sometimes craniofacial anomalies and other mutations

Question 15

Cenani-Lenz syndrome

Answer 15

Human syndactyly because of LRP4 mutation

Question 16

Environmental factors that affect embryogenesis

Answer 16

-Infection (especially viruses)
-Chemicals
-Nutrition
-Age fetus exposed is critical to nature of the defect

Question 17

Common viruses that causes developmental abnormalities

Answer 17

-Bovine diarrhea virus
-Feline panleukopenia virus
-Bluetongue virus

Question 18

Exposure to BVD before 100 days

Answer 18

Fetal death

Question 19

Exposure to BVD 100-170

Answer 19

Cerebellar, cerebral and ocular lesions

Question 20

Exposure to BVD after 170

Answer 20

Persistent infection and lymphoid atrophy

Question 21

Fetal infection with bluetongue virus in sheep

Answer 21

Damages developing neurons and get hydranencephaly earlier in gestation. Later in gestation get porencephaly

Question 22

Chemicals that cause develpomental problems

Answer 22

Time of infection is very important. Generally comes from plants

Question 23

Veratrum californicum in sheep

Answer 23

At 14 days gestation: cyclopia and severe craniofacial defects
29 days: metacarpal and metatarsal shortening
31 days: tracheal and larungeal stenosis

Question 24

Cyclopia in sheep

Answer 24

Severe manifestation of holoprosencephaly

Question 25

Holoprosencephaly

Answer 25

Disorder from failure of the embryonic forebrain to subdivide properly can be likd or severe

Question 26

What is veratrum californicum

Answer 26

Corn lily has cholesterol-like alkaloids

Question 27

What is the function of cholesterol

Answer 27

-Structural components of cell membranes. High ratios means low permeability and high stability -Precursor of steroid hormones and bile acids

Question 28

Shh gene/ hedgehog genes

Answer 28

Codes for protein needed for normal nervous system development during embryogenesis. It is a transcriptional regulatory protein. Must be cleaved by cholesterol to become active

Question 29

HH genes

Answer 29

Regulate cell proliferation and growth factors post-natally

Question 30

Shh mechanism of action

Answer 30

Shh binds to patched after activation to allow smoothened to function. When bound to patched is bound to Shh it senses cholesterol and regulates the amount in the cell and smoothened induces transcription and allows cholesterol trafficking and cell differentiation

Question 31

Veratrum and Shh

Answer 31

Binds to Shh but won't activate so this inhibits it leading to reduction in cholesterol activities and cell differentiation

Question 32

Nutrition on embryogenesis

Answer 32

Without proper nutrition you can get abnormal fetal development, whether it is from the mother not getting proper nutrition or uterine or placental abnormalities that prevent proper nutrition

Question 33

Vitamin A on embryogenesis

Answer 33

Involved in signal transduction pathways associated with development. Need to develop eyes, CVS, hindbrain, lungs, and skeleton

Question 34

Hypovitaminosis A

Answer 34

Brain and musculoskeletal abnormalities

Question 35

Hypervitaminosis A

Answer 35

CNS, craniofacial anomalies, cardiac, musculoskeletal and thymic malformation