Genetic Disorders II Flashcards

1
Q

Tx for lysosomal storage

A

enzyme replacement
substrate reduction
molecular chaperones

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2
Q

tay sachs disease

A

Gm2 - gangliosidoses storage disease

common in jews of European descent

motor and mental problems - 6 months of age
blindness and death by age 2-3

progressive neuronal destruction
cherry red spot in macula

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3
Q

Gm2 gangliosidose

A

tay sachs

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4
Q

hexosaminidase alpha-subunit deficiency

A

tay sachs

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5
Q

sphingomyelinase deficiency

A

nieman pick A and B
accumulation in sphingomyelin
common in ashrkenazic jews

type B - organomegaly - no CNS involvement - survive until adulthood

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6
Q

type A niemann pick

A

more common

  • manifest at birth
  • death within 3 years

protuberant abdomen (hepatosplenomegaly), failure to thrive, vomiting, fever, lymphadenpaothy, psychomotor dysfunction

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7
Q

Dx of nieman pickmann type A

A

liver or bone marrow Bx

-look for sphingomyelinase activity

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8
Q

niemann pick type C

A

mutation in NPC1 or NPC2
-cholesterol transport

cholesterol and gangliosides Gm1 and Gm2 accumulation

hydrops fetalis, neonatal hepatitis
-progressive neuro degeneration beginning in childhood with ataxia, dystonia, psychomotor regression

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9
Q

NPC1

A

mutated in nieman pick C

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10
Q

gaucher disease

A

autosomal recessive
mutation in glucocerebrosidase

accumulation of glucocerebroside

type I more common - non-neuronopathic - some enzyme
type II - neuronopathic - NO enzyme - death at early age
type III - intermediated

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11
Q

glucocerebrosidase

A

mutated in gaucher disease

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12
Q

type I gaucher disease

A

in european jews

  • non-neuronopathic
  • splenomegaly and lymphadenopathy
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13
Q

mucopolysaccharidoses

A

deficient enzyme that degrade glycosaminoglycans

coarse facial features, hepatosplenomegaly, corneal clouding, valve thickening, joint stiffness, mental retardation

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14
Q

hurler syndrome

A

MPS 1-H
deficient alpha-1 iduronidase

onset 6-24 months
death age 6-10 (cardiovascular)

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15
Q

hunter syndrome

A

MPS II

lacking corneal clouding - less severe than hurler

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16
Q

von gierke disease

A

glycogen storage disease
deficient glucose 6 phosphatase
-hepatic enlargement and hypoglycemia

hepatic type - treatable - but with late complications

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17
Q

mcardle disease

A

glycogen storage disease
muscle cramps after exercise, low lactate after exercise
deficient muscle phosphorylase

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18
Q

pompe disease

A

glycogen storage disease
deficient acid maltase
-cardiac involvement prominent (cardiomegaly)

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19
Q

alkaptonuria

A

ochronosis - blue black pigment of ears, nose, cheeks
-autosomal recessive
deficient homogentistic oxidase
blocks phenylalanine metabolism

homogentistic acid accumulation
-black color in urine

clinically evident - age 30s

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20
Q

giemsa stain

A

G-banding

-to determine karyotype

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21
Q

G-band organization

A

arm (p,q)
region
band
sub-band

Xp21.2

chromosome X, p arm, region 2, band 1, sub band 2

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22
Q

aneuploidy

A

not an exact multiple of 3

caused by nondisjunction

and anaphase lag

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23
Q

roberstonian translocation

A

results in one large and one small chromosome

24
Q

balanced reciprocal tanslocation

A

results in no net gain or loss of genetic material

25
Q

isochromose

A

one arm lost, remaining arm duplicated

26
Q

trisomy 21

A

down syndrome
common 47, XY, +21

influenced in maternal age

Dx: flat facies oblique palpebral fissure, epicanthic folds, simian hand creases
mental retardation
heart disease
risk for acute leukemia

live to age 47

27
Q

trisomy 18

A
edwards syndrome
severe malformations, die within first year of life
prominent occiput
overlap fingers
limited hip abduction
28
Q

trisomy 13

A

patau syndrome
severe malformations, die within first year of life

microcephaly
umbilical hernia
cleft palate and lip

29
Q

chromosome 22q11.2 deletion syndrome

A

digeorge syndrome -T cell deficiency and hypocalcemia

velicardiofacial syndrome - heart defect, facial dysmorphism, palate abnormalities,

30
Q

lyons hypothesis

A

only one X chromosome is active

31
Q

Y gene

A

has SRY

-determines testicle formation

32
Q

klinefelter syndrome

A

47XXY
male hypogonadism
-elongated body
-reduced spermatogenesis - infertility

nondisjunction during meiosis

33
Q

turner syndrome

A
monosomy of X
-hypogonadism in females
45X
neck webbing
heart disease
failure to develop secondary sex characteristics

short stature and amennorhea

34
Q

true hermaphrodite

A

both testicular and ovarian tissue

most 46XX

35
Q

female pseudohermaphrodites

A

46, XX
normal ovaries and internal genitalia
ambiguous external genitalia

steroid exposure during gestation

36
Q

male pseudohermaphrotdites

A

gonads are testes
-external genitalia are female or ambiguous

due to androgen insensitivity

complete testicular feminization

37
Q

fragile X syndrome

A

trinucleotide repeat mutation
familial mental retardation
FMR-1 gene

mental retardation and enlarged testicles elongated face, large mandible

38
Q

FMR -1 gene

A

fragile X syndrome

39
Q

47XXY

A

klinefelter

40
Q

monosomy X

A

turner

41
Q

edwards

A

trisomy 18

42
Q

patau

A

trisomy 13

43
Q

leber hereditary optic neuropathy

A

bilateral loss of central vision

  • age 15-35
  • eventual blindness

mutation in mitochondrial gene
-from mother

44
Q

maternal imprinting

A

silencing of the maternal allele

45
Q

paternal imprinting

A

silencing of the paternal allele

46
Q

prader willi

A

deletion of q12 on chromosome 15 paternal allele

short, hypotonia, hyperphagia, obesity, small hands and feet, hypogonadism

47
Q

angelman syndrome

A

deletion of q12 on chromosome 15 of maternal allele

retarded, ataxic gait, seizures, inappropriate laughter
-happy puppets

48
Q

gonadal mosaicism

A

results from mutations that affect cells that form gonads

-offspring manifest the disease

49
Q

indications for genetic analysis in mothers

A
over age 35
previous problems
ultrasound deformities
abnormal triple test (AFP, betaHCG, estriol)
carrier of X-linked disease
50
Q

indications for postnatal genetic analysis

A

congenital anomalies
mental retardation unexplained
suspected chromosomal abnormalities

51
Q

analysis of acquired genetic alterations

A

Dx and management of malignancy and infectious disease

52
Q

direct recombinant DNA

A

sequence gene

53
Q

indirect recombinant DNA

A

association with markers

54
Q

SNP

A

single nucleotide polymorphism

55
Q

repeat length polymorphisms

A

microsatellites - 2-6 bp, 1 kb length

minisatellite - 15-70 bp, 1-3kb length

56
Q

epigenetic alterations

A

heritable genetic changes without change in DNA sequence

57
Q

RNA analysis

A

for RNA virus

chromosomal translocation analysis