Diseases

Question 1

Cystic Fibrosis: Genetic Inheritance

Answer 1

-Genetic Inheritance: Autosomal Recessive

Question 2

Cystic Fibrosis affected protein and pathway function

Answer 2

-Protein & Function: Decrease/Loss of CFTR protein, as a result chloride channels are blocked/inactive and chlorine cannot be excreted (therefore sodium, therefore H20)

Question 3

Cystic Fibrosis Clinical Manifestations

Answer 3

Clinical Manifestations: unable to hydrate mucus leading to blocked ducts/tracts (pancreas, GI, reproductive organs) salty skin, malnutrition, greasy stools

Question 4

Cystic Fibrosis Diagnosis

Answer 4

1. Screening of immunoreactive trypsinogen (IRT) blood levels
2. If positive screening, QPIT sweat test performed
3. For a specific gene/location exon sequencing is the most straightforward method

Question 5

Cystic Fibrosis Treatment (Direct & Indirect)

Answer 5

Direct Treatment of Defect:

• Ivacaftor: facilitates opening of chloride ion transport increasing hydration of cellular secretions
• Lumacaftor-Ivacaftor: improves conformational stability of the deletion F508-CFTR gene, leading to increased amounts of the mature protein on the cell surface

Indirect Treatments:

• Chest physiotherapy
• Bronchodilators
• Mucolytics
• Hypertonic saline

Question 6

t(9,22) name and genetic inheritance

Answer 6

Name: Philadelphia Chromosomal translocation
Genetic Inheritance: Robertsonian translocation (chromosomal translocation involving long arm regions of acrocentric chromosomes)

Question 7

t(9,22) mechanism and affected genes

Answer 7

Robertsonian translocation, long arm from chromosome 9 is translocated to chromosome 22 and the q arms are fused together to create one long chromosome. ABL gene is move from chromosome 9 to chromosome 22 and placed next to BCR gene in the process. ABL codes for tyrosine kinase enzyme which leads to overexpression of hybrid gene BCR-ABL and uncontrollable cell growth and division –> cancer

Question 8

t(9,22) associated disorders

Answer 8

• CHRONIC MYELOGENOUS LEUKEMIA (CML)

- Acute Lymphoblastic Leukemia (ALL)

Question 9

Cri-du-chat syndrome genetic inheritance and symptoms

Answer 9

• Chromosomal deletion of short arm on chromosome 5

- Causes: microcephaly (small head), intellectual disability, high-pitched cry, and cardiac abnormalities

Question 10

William’s Syndrome genetic inheritance and symptoms

Answer 10

• Chromosomal deletion on long arm of chromosome 7

- Symptoms: “elf-like” features, intellectual disability, extreme friendliness

Question 11

Down Syndrome Genetic Inheritance

Answer 11

Trisomy 21 due to meiotic nondisjunction (95% of the time)

Question 12

Edwards Syndrome Genetic Inheritance

Answer 12

Trisomy 18 due to meiotic nondisjunction

Question 13

Patau Syndrome Genetic Inheritance

Answer 13

Trisomy 13, meiotic nondisjunction

Question 14

Clinical Signs: Flat facies, prominent epicanthal folds, single palmar crease, gap between first and second toes

Answer 14

Down Syndrome/Trisomy 21

Question 15

Clinical Signs: micrognathia, prominent occiput, low set ears, clenched hands overlapping fingers, rocker-bottom feet, limited hip adduction

Answer 15

Edwards Syndrome/Trisomy 18

Question 16

Clinical signs: cutis aplasia, microcephaly, holoprosencephaly, cleft lip/palate, polydactyly, rocker-bottom feet

Answer 16

Patau Syndrome/Trisomy 13

Question 17

Chronic Myeloid Leukemia stems from what chromosomal translocation?

Answer 17

t(9,22) Philadelphia Chromosome

Question 18

Chronic Myeloid Leukemia (CML) characterized by what symptoms and what will always be a strong indication of CML?

Answer 18

• ELEVATED BASOPHILS almost always immediately point to Chronic Myeloid Leukemia
• Characterized by neutrophils proliferating uncontrollably in the bone marrow and spilling out into the blood