Week 1 - Genetics

Question 1

Epigenetics definition:

Answer 1

1. Epigenetics definition: Epigenetics is the study of how genes are expressed or regulated. Epigenetics are contained in the histone proteins that package human’s DNA. Environmental and psychosocial factors during a person’s lifetime or their parent’s lifetime may influences how one’s epigenetics changes a gene expression. A person’s genetic sequence does not change, while the epigenetics that encloses the DNA can change
   
   1. Multiple locations on gene that can cause disease
   2. External factors that can cause mutations in genes (sun light, diet, chemicals, environmental, behavioral)

Question 2

Prader-Willi Syndrome

Answer 2

1. Prader-Willi Syndrome: from father, chromosome 15
   
   1. Deletions of 4 million base (Mb) pairs
   2. Short stature, hypotonia, small hands and feet, obesity, mild-to-moderate mental retardation, hypogonadism, wide nipples
   3. “Willi” = father of 15

Question 3

Angelman Syndrome:

Answer 3

1. Angelman Syndrome: from Mother, chromosome 15
   
   1. 4-Mb deletions
   2. Laugh a lot, problems with complex cognitive problems (severe mental retardation), seizures, ataxic gait
   3. “Angel” = mother of 15

Question 4

Beckwith-Wiedemann Syndrome

Answer 4

1. Beckwith-Wiedemann Syndrome
   
   1. 20-30% genetic. 2 copies of a chromosome from father & none from mother
      
      1. Uniparental disomy on chromosome 11
   2. Overgrowth condition accompanied by an increased predisposition to cancer
      
      1. Wilms tumor or hepatoblastoma > regular screenings
   3. Identifiable at birth
      
      1. Large for gestational age; neonatal hypoglycemia; large tongue; creases on the ear lob; omphalocele; and, hemihyperplasia

Question 5

Heterozygous

Answer 5

One dominate and one recessive gene Aa

Question 6

Homozygous

Answer 6

AA (homozygous Dominate) or aa (homozygous recessive)

Question 7

Phenotype

Answer 7

express of trait

Question 8

Down Syndrome - memorize

Answer 8

1. Down Syndrome (Trisomy 21) memorize
   
   1. XXX
   2. 80% reach age 60, 1 in 800 births
   3. Could be related to b12 as we age there is decrease levels of vitamins. Take prenatal 2-3 months prior to getting pregnant
   4. Ultrasound measure head and spine ratios (not always accurate). Amniocentesis is the only way to determine if baby has down syndrome
   5. Non-disjunction – 95% (does not pull apart during metaphase)
   6. Translocation – one chromosome from 14 mores to chromosome 21
   7. Singl crease in palms of hand, small haed with flat flacial features, slanted eyes
   8. Heart defects, leukemia (ALL), Dementia - 25% over 35 yo
   9. May have decrease IQ and speech difficulities
   10. amniocentesi & karyotype test

Question 9

Turner Syndrome

Answer 9

1. Turner Syndrome XO = 45X
   
   1. One X – do not produce estrogen
   2. 1 in 2500 births
   3. Women because there is no Y (no testoterson production)
   4. Webbed neck, infertility
   5. No breast development, widely spaced nipples
   6. Chromosomal testing
   7. Hormone Therapy – Growth Hormone and estrogen at puberty

Question 10

Klinefelter Syndrome

Answer 10

1. _Mr Kline_felter Syndrome XXY = 47X
   
   1. Still releases testosterone > considered a male with female characteristics
   2. The extra X cause extra estrogen to be released during puberty (no female reproduction system)
   3. Both maile and femail Sexual characteristics
   4. gynecomastic, reduced body hair, decreased testosterone
   5. Infertility (95-99%, low spern count, small testes
   6. impaired language
   7. Chromosomal testing and GH

Question 11

Huntington’s Disease

Answer 11

1. Huntington’s Disease
   
   1. chromosome 4, Autosomal dominant (Aa or AA)
      
      1. Aa – pass on to kid (50% chance) if spouse is aa. If AA – 100% chance to pass onto kids
   2. Chromosome 4 – CAG repeats
      
      1. <=36 could have HD
   3. Progressive degeneration of nerve cells; loss of GABA neurons (inhibitory) within the basal ganglia
   4. Chorea
   5. MRI/CT

Question 12

1. Dwarfism

Answer 12

1. Dwarfism
   
   1. Adult height of less of 4 feet 10 inces or less
   2. Achondroplasia (a – w/o, chondro – cartilage)
   3. 2 Types
      
      1. Achondroplasia – torso normal and extremities short
         
         1. autosomal dominant (AD1/8) and spontanteous 7/8
      2. Primordial – proportionally small
   4. Hip deformities, clubfoot,

Question 13

Sickle Cell Anemia

Answer 13

1. Sickle Cell Anemia
   
   1. Autosomal recessive
   2. Won’t get malaria
   3. Know pathophysiology of sickle Cells
      
      1. The gene changed from Glutamate (HbA) to Valine (HbS)
      2. Test smear see sickle cell shape
      3. Sickling of cells abdominal and bone pain, ulcerations, thrombi, infarcts
      4. Hemolytic crisis - jaundc and hematuria
      5. Splenic sequestration crisis > prone to infections > hypovolemic > death
      6. Aplastic crisis: RBCs live 10-20 dyas, infect by parvovirus
      7. HbF – when women are pregnant
      8. Treatment for sickle cell –
         
         1. give HbF
         2. Hydroxyurea stimulates Hb F
         3. antibiotics
      9. Splenomegaly because HgS turn over in 10-20 days instead of 120 days. B pain from producing more HbS. The liver is taxed from breaking down hem in RBCs.
      10. Increased reticulocyte count (baby blood cells)