Genetic Disorders

Question 1

One dominant allele is enough to produce phenotype

Answer 1

Autosomal dominant

Question 2

Variable expression:

proportion of those who inherit the gene and express its phenotype

Answer 2

Penetrance

Question 3

Variable expression:

Variability in phenotypic expression among those who inherit the gene

Answer 3

Expressivity

Question 4

Gene defect in Marfans

Answer 4

Fibrillin-1 gene

Question 5

Loss of support in microfibril rich connective tissue

Tall, arachnodactyly, hyperextensible joints, ectopia lentis, mitral valve prolapse

Answer 5

Marfan syndrome

Question 6

Defect in fibrillar collagen

Structural proteins or enzymes

Answer 6

Ehlers-Danlos syndrome

Question 7

Autosomal recessive type of Ehlers-Danlos

Answer 7

Kyphoscoliosis Type 6
- lysyl hydroxylase
Dermatosparaxis Type 7c
- procollagen n- peptidase

Question 8

Diaphragmatic hernia is seen in this type of EDS

Answer 8

Classic EDS

Question 9

Hyperextensible skin
Hypermobile joints
Retinal detachment

Answer 9

Ehlers-Danlos

Question 10

Two recessive alleles produce the phenotype

25% chance of having the trait

Answer 10

Autosomal recessive

Question 11

Defect in a subunit of hexosaminidase A

Answer 11

Tay Sachs

Question 12

Accumulation if GM2 ganglioside in neurons and retina

Cherry red spot in retina
Whorled onion skin appearance cytoplasmic inclusions

Answer 12

Tay Sachs

Question 13

Defect in sphingomyelinase– accumulation of sphingomyelin

Answer 13

Niemann Pick

Question 14

Hepatosplenomegaly
Cherry red spot in macula
With neurologic damage
Infantile

Answer 14

Niemann Pick A

Question 15

Most common lysosomal storage disease

Answer 15

Gaucher

Question 16

Defect in Gaucher

Answer 16

Glucerebrosidase (B glucosidase) deficiency

Question 17

Fibrillary cytoplasm “crumpled tissue paper” appearance

Distended phagocytic cells in spleen liver BM thymus Peyers patches

Answer 17

Gaucher cells

Question 18

Autosomal recessive
a-L-Iduronidase deficiency 
With corneal clouding
More severe 
Coarse facial features, joint stiffness, mental retardation

Answer 18

Hurler syndrome

Question 19

X linked
L- iduronosulfate deficiency
No corneal clouding

Answer 19

Hunter

Hunter X Hunter

Question 20

Glucose 6 phosphatase deficiency
Decreased hepatic glucose output
Hypoglycemia

Answer 20

GSD 1 (hepatic)
Von Gierke

Question 21

Muscle phosphorylase deficiency
Decreased energy output
Myopathic glycogenosis

Answer 21

McArdle GSD V

Question 22

Lysosomal acid maltase deficiency

Cardiomegaly and cardiac failure within first 2 years

Answer 22

Pompe disease GSD 2

Question 23

All daughters are carriers

Males express phenotype

Answer 23

X linked disorders

Question 24

Most common chromosomal disorder

Answer 24

Trisomy 21

Question 25

Most common cause of Down syndrome

Answer 25

Nondisjunction of Ch21 during meiosis

Question 26

Most common leukemia associated with trisomy 21

Answer 26

Acute megakaryoblastic leukemia

Question 27

What distinguishes Patau from Edward syndrome in terms of manifestations?

Answer 27

Cleft lip and palate | Umbilical hernia

Question 28

Chromosome 22q11.2 deletion

Answer 28

DiGeorge

Question 29

CATCH 22 in DiGeorge

Answer 29

``` Cardiac anomalies Abnormal facies Thymic hypoplasia Cleft palate Hypocalcemia ```

Question 30

Persons with DiGeorge syndrome is also at high risk for

Answer 30

Schizophrenia | Bipolar disorder

Question 31

Important cause of reduced spermatogenesis and male infertility

Answer 31

Klinefelter syndrome | 47XXY

Question 32

``` Disorder of sex chromosome Testicular atrophy Micropenis Absence of secondary sex characteristics Gynecomastia Low IQ ```

Answer 32

Klinefelter syndrome

Question 33

Most common heart defect in Klinefelter's

Answer 33

Mitral valve prolapse

Question 34

Complete or partial monosomy of X chromosome | Single most important cause of primary amenorrhea

Answer 34

Turner syndrome | 45XO

Question 35

Ovarian streaks Absence of secondary sex characteristics Short stature Webbed neck

Answer 35

Turners

Question 36

Most important cause of increased mortality in children with Turners

Answer 36

Cardiovascular: Preductal COA Bicuspid aortic valve

Question 37

Mitral valve prolapse

Answer 37

Marfan | Klinefelter

Question 38

Disease worsens with each successive generation

Answer 38

Anticipation

Question 39

Second most common cause of MR after Trisomy 21

Answer 39

Fragile X syndrome

Question 40

Mutation in Fragile X

Answer 40

CGG expansion in FMR1 gene in the X chromosome

Question 41

Trinucleotide repeat disorder eith clinically long face, large mandible, large everted ears and marco orchidism

Answer 41

Fragile X

Question 42

Most distinctive feature of fragile X

Answer 42

Macro orchidism

Question 43

Autosomal dominant trinucleotide repeat with progressive movement disorders and dementia due to degeneration of striatal neurons

Answer 43

Huntington disease AMELIAAAA 😭😭😭😭

Question 44

Mutation in Huntington disease

Answer 44

CAG expansion on HTT gene on Ch4p16.3

Question 45

Mitochondrial disorders have this distinctive feature

Answer 45

Maternal inheritance

Question 46

Silencing of one copy of gene from either parent during gametogenesis

Answer 46

Imprinting

Question 47

Deletion in paternally derived chromosome 15q Mental retardation Hypotonia, profound hyperphagia, obesity, hypogonadism, small hands and feet

Answer 47

Prader Willi

Question 48

Deletion in maternal chromosome 15q12 Mental retardation Ataxic gait Inappropriate laughter " happy puppet"

Answer 48

Angelman syndrome

Question 49

Thrush Diaper rash Failre to thrive Morbiliform rash due to graft bs host disease

Answer 49

SCID

Question 50

Hyper IgM sundrome is due to

Answer 50

CD40L absence or mutation in cytidine deaminase

Question 51

Hyper IgM syndrome can cause

Answer 51

Pyogenic infections, pneumocystis jiroveci

Question 52

Triad of wiskott aldrich syndrome

Answer 52

Thrombocytopenia Infections Eczema

Question 53

``` Autosomal recessivr ATM gene Ataxia, vascular malformations, neurologic deficits Increased incidence of tumors IgA and IgM deficiency ```

Answer 53

Ataxia telangiectasia

Question 54

Starch like misfolded proteins most commonly in the kidney Amyloid deposits always extracellular Congo red: apple green bifringence Sago spleen

Answer 54

Amyloidosis

Question 55

``` Defect in CFTR gene Ch7 q31.2 Salty sweat Bronchiectasis, cirrhosis Acidic secretions- chronic metabolic alkalosis Pancreatic insufficiency Digital clubbing Obstructive azoospermia Increased sweat chloride concentration ```

Answer 55

Cystic fibrosis

Question 56

Most common organisms involved in secondary infections of cystic fibrosis

Answer 56

S. aureus H. influenzae P. aeruginosa