Chromosomal Abnormalities

Question 1

Down’s - Inheritance

Answer 1

Chromosomal Number

Question 2

Down’s - Karyotype

Answer 2

Trisomy 21: 47, XX/XY, +21

Question 3

Down’s - Mechanism

Answer 3

95% in every cell
Due to nondisjunction in maternal meiosis I

3% Robertsonian Translocation
Extra 21 fused with chromosome 14 (46 chromosomes)
46, XX, der(14;21)(q10;q10)+21

2% Mosaic Down’s
47, XX +21/46XX

Question 4

Down’s - Clinical Presentation

Answer 4

Congenital heart disease (50%)
endocardial cushion defect, atrioventricular canal

GI tract defects (10-15$)
esophageal or duodenal atresias (no swallowing)

Ophthalmologic
Endocrine, orthopedic, hematologic, psychiatric

mid face hypoplasia (small features mid face)
hypotonia
brachecephaly (short skull)

Question 5

Edwards Syndrome - Inheritance

Answer 5

Chromosomal number

Question 6

Edwards Syndrome - Karyotype

Answer 6

Trisomy 18: 47, XX/XY, +18

Question 7

Edwards Syndrome - Mechanism

Answer 7

Translocation: der(14, 18)

Question 8

Edwards Syndrome - Clinical presentation

Answer 8

low survival rate
congenital malformations
heart disease, CND maldevelopment, diagraphmatic hernias, renal defects, seizures

hypertonicity (clenched hands, narrow hips)
rocker bottom feet

Question 9

Patau Syndrome - Inheritance

Answer 9

Chromosomal Number

Question 10

Patau Syndrome - Karyotype

Answer 10

Trisomy 13

Question 11

Patau syndrome - Mechanism

Answer 11

20% translocation derived
majority robertsonian translocation
familial and de novo

Question 12

Patau syndrome - Clinical presentation

Answer 12

most severe
sever intellectual disability
congenital malformations
fusion of brain loves, polydactyly, renal problems

Question 13

22q11.2 syndrome - Inheritance

Answer 13

Chromosomal number

Question 14

22q11.2 syndrome - Associated Gene

Answer 14

TBX-1

Question 15

22q11.2 syndrome - Mechanism

Answer 15

Disturbance of migration of neural crest cells into pharyngeal arches/pouches

Question 16

22q11.2 syndrome - Clinical presentation

Answer 16

Cleft lip/palate
heart defects
thymus defects : T cell dysfunction
parathyroid defects: hypocalcemia

Question 17

APMLeukemia - Inheritance

Answer 17

translocation 15 & 17

Question 18

APMLeukemia - Associated genes

Answer 18

PML

RARalpha

Question 19

APMLeukemia - Karyotype

Answer 19

t(15;17)(q22;q21)

Question 20

APM Leukemia - Mechanism

Answer 20

prevents differentiation

Question 21

APM Leukemia - Treatment

Answer 21

vitamin A - remission; changes conformation of protein

Question 22

Chronic Myeloid Leukemia (CML) - Inheritance

Answer 22

Translocation chr. 22 & 9

Question 23

CML - Associated genes

Answer 23

ABL1

BCR

Question 24

CML - karyotype

Answer 24

T(9;22)(q34;q11)

Question 25

CML - Mechanism

Answer 25

Portion of 22 goes on 9, leads to progression gain of aditional 8, 22, etc.

Type of AML

Question 26

CML - Clinical presentation

Answer 26

Splenomegaly
Night sweats
Fatigue
Weight loss
Increased susceptibility to infections
Thrombocytopenia, bruising

Question 27

CML - treatment

Answer 27

with Gleevec (tyr kinase inhibitor)