Quiz 3 part 3

Question 1

What are the lab values of Klinefelter’s related to testosterone?

Answer 1

Hypogonadism is the most consistent finding, the plasma FSH levels are consistently elevated and testosterone levels are reduced

Question 2

The pathology of low testosterone and high FSH levels is related to what?

Answer 2

Reduced spermatogenesis and male infertility. The testicular tubules are totally atrophied, and replaced by pink, hyaline, collagenous shells. Large Leydig cells may contribute to atrophy.

Question 3

What is the classical congenital heart defect with Turners syndrome

Answer 3

Coarctation of the Aorta and Bicuspid aortic valves
- remember, cardiovascular abnormalities are the single most important cause of increased mortality in children with Turners

Question 4

What is a cystic hygroma

Answer 4

Distended lymphatic channels causing a webbing of the neck.

- Seen in Turner Syndrome

Question 5

Genetics of Hungtington’s disease

Answer 5

Autosomal dominant disorder

• HD gene is located in chromosome 4
• gene codes for production of an altered protein Huntingtin, that is expressed in body and nervous system by both neurons and glial tissue

Question 6

What is one of the purest examples of a true autosomal completely dominant disorder

Answer 6

Huntingtons disease

Question 7

Genetics of Marfan’s syndrome

Answer 7

Autosomal dominant disorder

Dysfunction of gene on chromosome 15 that codes for Fibrillin

Question 8

The disorder of CT see in Marfan’s syndrome is manifested by changes where?

Answer 8

Skeletal system
Eyes
Cardiovascular system

Question 9

Explain changes of skeletal system in Marfan’s syndrome

Answer 9

Slender and tall, elongated head, prominent frontal bossellation, arachnodactyly, frequent luxations and spinal deformities

Question 10

Explain changes of CV system in Marfan’s syndrome

Answer 10

Dilatation of aorta, fraying of tissues, floppy valves, valves malfunction, mitral valve prolapse and regurgitation leading to heart failure and death

Question 11

Explain changes of eyes in Marfan’s syndrome

Answer 11

Displaced lens, cataracts, retinal detachments, blindness

Question 12

Genetics involved with Cystic Fibrosis

Answer 12

Defect in gene that normally codes for protein forming Chloride Transport channel in the cell membrane causing Cl transport defect across cell membrane leading to lack of NaCl in glandular secretions of all exocrine glands
- This leads to secretions with less water and are viscid leading to obstruction of lumens of organs.

• Most common autosomal recessive disease
• Almost only seen in Caucasians

Question 13

Most common autosomal recessive disease?

Answer 13

Cystic fibrosis

Question 14

What are the 3 most important glands affected by cystic fibrosis

Answer 14

Pancreas - malabsorption, malnutrition, etc.
Intestines - infant; stool with undigested food, bulky, stinky
Bronchi - pneumonia, lung abscesses, bronchitis
- Most important complication is hyperviscosity of bronchial mucous making viscous plugs to prevent respiration

Question 15

What is a sweat test and what disease do you use it for?

Answer 15

Measures the chloride concentration that is excreted in sweat.
Used to screen for Cystic Fibrosis

• Due to defect Chloride channels, elevated levels of chloride will be seen in a person with CF

Question 16

What is Osteogenesis Imperfecta?

Answer 16

A group of heritable disorders of connective tissue, caused by mutations in the gene for type 1 collagen
- Autosomal dominant

Question 17

Where are the genes that cause OI located?

Answer 17

These genes are located on Chromosome 17 and chromosomal 7, respectively (COL1A1 and COL1A2)

Question 18

Mutations of what gene in OI are seen in all types of OI?

Answer 18

Mutations of COL1A1 are seen in all types of OI, and affects about 3/4 of the Type I collagen molecule
- Mutations of COL1A2 affects about half of the synthesized collagen molcule

Question 19

How many types of OI?

Answer 19

4 types, each with a different genetic structural abnormality and clinical features

Question 20

What is the layman term for OI?

Answer 20

Brittle bone disease

Question 21

What teeth malformations are seen in OI?

Answer 21

Because of the hypoplasia of the dentine and pulp, the teeth are misshapen and bluish - yellow in color

Question 22

What two disorders having to do with hyaline membrane disease of the newborn has to do with charged oxygen radicals?

Answer 22

1. Retrolental fibroplasias
   
   • long-term, high concentrations of O2 can produce O2 radicals that can lead to toxicity in the eyes of newborn
2. Bronchopulmonary Dysplasia
   
   • Complication of high O2 concentration and toxicity due to O2 radicals
   • Fibrosing condition of peribronchial and interstitial tissue leading to wall thickening

Question 23

Which congenital heart defect is associated with hyaline membrane disease because of prematurity?

Answer 23

Patent Ductus Ateriosus (PDA) due to prematurity

• Mortality rate is about 50% in infants weighing around 1000 grams
• 24-28 weeks gestation, 20-30% in infants over 30 weeks

Question 24

What is Fragile X Syndrome

Answer 24

The most common form of inherited mental retardation due to a defect on the long arm of the X Chromosome
- Second only to Trisomy 21 as an identifiable cause of mental retardation

Question 25

What is a fragile site?

Answer 25

a specific site is a specific site or locus on a chromosome that breaks easily. there may be as many as fifty fragile sites on autosomes and sex chromosomes

Question 26

What locus is associated with mental retardation?

Answer 26

Xq27

Due to a repeat of an amino acid sequence (CGG)

Question 27

Although male newborns with fragile X syndrome appear normal, what characteristics begin to appear during childhood

Answer 27

1. Increased head circumference
2. Facial coarsening
3. Joint hyperextensibility
4. Enlarged Testes
5. Abnormalities of the cardiac valves
   6 Mental retardation is profound

Question 28

What % of Fragile X syndrome males who exhibit the fragile site are mentally retarded?

Answer 28

80%

The other 20% are clinically normal, but can transmit the trait

Question 29

T or F, Of the females who are known to bear the fragile X chromosome, 1/3 are intellectually normal, and the other 2/3 are mentally retarded

Answer 29

False, 2/3 normal, 1/3 retarded

Question 30

What is Duchenne Muscular Dystrophy?

Answer 30

A severe X-linked (only males affected) recessive disorder of muscle caused by a mutation of the gene DMD

Question 31

What is the pathogenesis of DMD

Answer 31

DMD codes for the protein Dystrophin, an important structural component within muscle tissue
- The pathogenesis relates to Dystrophin-deficient muscle fibers that lack the normal interaction between the sarcolemma and the extracellular matrix

Question 32

DMD is characterized by what?

Answer 32

Progressive degeneration of muscles, particularly those of the pelvic and shoulder girdles

Question 33

What is the most common non-inflammatory myopathy in children

Answer 33

DMD

Question 34

What is Gowers sign and what is the protein that is deficient in Duchenne Muscular Dystrophy?

Answer 34

Gower sign: a positive Gower sign is represented when a child helps himself to get up with his upper extremities: first by rising to stand on his arms and knees, and then “walking” his hands up his legs to stand upright
- Protein is Dystrophin