Genetics Flashcards

1
Q

Karyotype of Down syndrome

A

Trisomy 21

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2
Q

T/F
Blank facial expression is common in Down syndrome

A

False

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3
Q

Typical features in Down syndrome

A

Microcephaly
Low, flat nasal bridge
Oblique upward- slanting eyes
Low set ears
Short nose
Open mouth
Large protruding tongue
Single palmar crease
Saddle gap
Hypotonia
Hepatosplenomegaly

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4
Q

Down syndrome is associated with (complications)

A

Leukemia- Hepatosplenomegaly
Anal abnormalities
Duodenal atresia
Hirschsprung disease
Developmental delay
Hypothyroidism

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5
Q

The growth chart used in down syndrome

A

Down syndrome specific growth chart

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6
Q

Ways how trisomy 21 occurs in down syndrome

A

Non- disjunction (95% of the cases)
Translocation 4%
Mosaicism 1%

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7
Q

Risk of recurrence of Down syndrome is highest in

A

Translocation ( 21:21 translocation is 100%)

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8
Q

Low- set ears

A

At least 1/3 of the ear doesn’t protrude out from an imaginary line drawn from the outer corner of the eye and the eye

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9
Q

confirmatory test in Genetic disorders

A

Karyotyping

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10
Q

Referrals that should be done for Down syndrome

A

Cardiology

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11
Q

Steps of Mx if there’s a developmental delay in down syndrome

A

Refer to rehabilitation programs
Physiotherapy
Speech therapy
Hearing assessment
Visual assessment

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12
Q

Mx of down syndrome

A

1.Karyotyping - confirm the Dx
2.Ix for possible complications( Echo, USS Abd, CBC, Blood picture, Thyroid function test)
3.Growth and development assessment
4.Thyroid supplementation ( if hypo)
5.Refer to a cardiologist ( if cardiac issues)
6.Refer to a special school
7.If there’s a growth delay - refer to rehabilitation programs
8. Genetic counselling to parents

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13
Q

2nd Most common trisomy

A

Edward syndrome

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14
Q

Edward syndrome is most seen in males/females?

A

females (80%)

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15
Q

T/F
Majority of edward syndrome will be stillbirths

A

True

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16
Q

Reason for low survival rate in Edward syndrome

A

Heart abnormalities
Kidney malformations

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17
Q

Sx of Edwards Syndrome

A

Small head
malformed ears
Widely- spaced eyes
Clenched hands
low set ears
overlapping fingers

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18
Q

Widely- spaced eyes?

A

gap between the two eyes is more than the gap for one eye

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19
Q

Sx of patau Syndrome

A

Small head
Cleft lip/ palate
Absent eyebrows
Dysplastic/ malformed ears
Clenched hands
Polydactyly
Undescended or abnormal testes

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20
Q

Karyotype of Patau syndrome

A

Trisomy 13

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21
Q

Turner syndrome karyotype

A

45 chromosomes. XO

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22
Q

Most cases of turner syndrome is diagnosed late. When?

A

When performing tests for being unable to get PG

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23
Q

Hormone deficiencies in Turner syndrome

A

Reduced GH
Reduced estrogen
Reduced Thyroxine

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24
Q

Sx of turners

A

Short stature
Low posterior neckline
Webbing of neck
Shield chest
Edema of dorsum of hands and feets
Cubitus varus
Rudimentary ovaries, uterus
Cardiac abnormalities

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25
Q

shield chest is seen in

A

Turner syndrome - widely spaced nipples

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26
Q

low set ears are seen in

A

Down syndrome
Edward syndrome

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27
Q

How is the cognition in turner syndrome

A

Mostly normal

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28
Q

Mx of turner syndrome

A

Educate the parents- genetic counselling
Refer to a cardiologist
Hormone replacement therapy
Family planing advices

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29
Q

Common cardiac complication associated with turner

A

CoA

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30
Q

Cubitus varus seen in

A

Turner syndrome

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31
Q

Saddle gap is seen in

A

Down syndrome

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32
Q

3 GIT conditions associated with Down syndrome

A

Duodenal atresia
Hirschsprung disease

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33
Q

Klinefelters syndrome karyotype

A

44 XXY

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34
Q

Klinefelter syndrome presents as male/female

A

both males and females

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35
Q

Klinefelter Syndrome

Epidemiology

A

1 in 500 to 1000 births

36
Q
A
36
Q

Klinefelter Syndrome

Males are usually sterile (T/F)

A

T

37
Q

Klinefelter Syndrome

Sx

A
  • Youthful build
  • Rounded body type- feminine fat distribution
  • Some degree of gynecomastia
  • Hypogonadism
  • Both male and female features
  • No bitemporal baldness
  • Taller than average height
  • Reduced facial, body hair
  • Osteoporosis risk high
  • Small testes- atrophy
38
Q

Klinefelter Syndrome

IQ

A

generally poor

39
Q

Klinefelter Syndrome

They are generally attracted to males/ females?

A

not generally attracted to females

40
Q

Autosomal Dominant disorders

% of diseased, carriers, healthy

A
  • 50% Diseased
  • 0% carriers
  • 50% healthy
41
Q

Autosomal dominant disorders

carriers?

A

No carriers in AD

42
Q

Autosomal dominant disorders

New mutations are not possible (T/F)

A

F

43
Q

Autosomal dominant disorders

Examples of AD

A
  • Hereditary spherocytosis
  • Marfan’s
  • Achondroplasia
  • Ehlers- Danlos Xs
  • VwD
  • Tuberous sclerosis
  • Noonan Xd
44
Q

Autosomal dominant disorders

When making pedigree charts the assumption we make

A

We assume one parent is normal, one parent is affected

45
Q

Autosomal dominant disorders

Achondroplasia Sx

A
  • Short stature- cannot touch their own shoulders by their hands
  • developmental delay
46
Q

Autosomal dominant disorders

Ehlers- Danlos Syndrome

A
  • Hypermobile joints
  • Stretchable skin
  • Aortic abnormalities
47
Q

Autosomal dominant disorders

Tuberous sclerosis Sx

A
  • Ash leaf macules
  • Shagreen patch- palpable
  • Adenoma sebaceum
  • Seizures
48
Q

Autosomal dominant disorders

Marfan Syndrome Sx

A
  • Tall, thin build
  • Flexible joints
  • Upward dislocation of lens
  • Occular HTN- glaucoma
  • Crowded teeth
  • High arched neck
  • Pectus excavatum, carinatum, scoliosis
  • Stretch marks
  • Disproportionately long arms, legs
  • Arachnodactyly
  • Flat feet
49
Q

Autosomal dominant disorders

Cardiac abnormalities seen in Marfans

A
  • Aortic aneurysm
  • Aortic dissection
  • Mitral valve prolapse
50
Q

Autosomal dominant disorders

Nervous system, Respi system complocations seen in Marfans

A
  • Nervous- dural ectasia
  • Respi- pneumothorax (bullae)
51
Q

Noonan Syndrome

affects only males (T/F)

A

F- affects both male and female

52
Q

Noonan syndrome

Sx

A
  • disproportionately large head
  • High anterior hairline
  • Triangle- shaped face
  • Transparent, wrinkled skin
  • Prominent nasolabial folds
  • Neck webbing
  • wide- spaced eyes
53
Q

Noonan Syndrome

Complications

A
  • R/ heart problems- Pulmonary stenosis
54
Q

L/ heart problems are seen in

A

Turner Syndrome

55
Q

Autosomal Recessive Disorders

% of normal, carriers and affected

A
  • 25% normal
  • 50% carriers
  • 25% affected
56
Q

Autosomal Recessive Disorders

Assumption we make

A

We assume both parents are carriers

57
Q

Autosomal Recessive Disorders

Common among

A

consanguineous marriages

58
Q

Autosomal Recessive Disorders

To occur

A

child should have 2 abnormal chromosomes, one from each parent.

59
Q

Autosomal Recessive Disorders

Some examples

A
  • Congenital adrenal hyperplasia
  • Cystic fibrosis
  • Albinism
  • Phenylketonuria
  • Sickle cell disease
60
Q

Autosomal Recessive Disorders

Cystic fibrosis Pathophysiology

A
  • Thick airway secretions- recurrent infections
  • Secretions block the pancreas- lipase not produced
  • Lipids not digested properly- steatorrhea
61
Q

Autosomal Recessive Disorders

Cystic fibrosis is seen

A

common in caucasians- not much seen in SL

62
Q

Autosomal Recessive Disorders

Phenylketonuria pathophysiology

A

No PKU to convert phenylalanine to tyrosine.
Toxic levels of Phenylalanine

63
Q

Autosomal Recessive Disorders

Sx of PKU

A
  • Mental retardation
  • Skin rashes
  • Behavioral problems
  • Convulsions
  • Musty body odor
64
Q

Autosomal Recessive Disorders

Mx of PKU

A
  • Avoid meat, dairy, dry beans. nuts, eggs
  • Give Phenylalanine free milk powder- very expensive
65
Q

Autosomal Recessive Disorders

Sx of sickle cell disease

A
  • Fatigue
  • jaundice
  • Breathless
  • body pains
  • swelling of arms, legs
  • arthralgia
66
Q

Autosomal Recessive Disorders

Characteristic face seen in Sickle cell anemia

A
  • Frontal bossing
  • malar prominence
  • crowded teeth
67
Q

X linked recessive disorders

% of healthy, carriers and affected girls

A
  • 50% carriers
  • 50% healthy
  • NO AFFECTED
68
Q

X linked recessive disorders

% of healthy, affected and carrier boys

A
  • 50% affected
  • 50% healthy
  • NO CARRIERS
69
Q

X linked recessive disorders

Which genetic disorder can have a high risk of getting X linked recessive disorders

A

Turner Syndrome

70
Q

X linked recessive disorders

Examples

A
  • colour blindness
  • Duchenne muscular dystrophy
  • Fragile X syndrome
  • Hemophilia
71
Q

X linked recessive disorders

Charts used to Dx colour blindness

A

Ishihara charts

72
Q

X linked recessive disorders

Duchenne muscular dystrophy Dx

A

Muscle Biopsy

73
Q

X linked recessive disorders

Duchenne Sx

A
  • Calf pseudohypertrophy
  • thin weak thighs
  • weak buttock muscles
  • shoulders and arms held back awkwardly when walking
  • swayback posture
74
Q

X linked recessive disorders

Duchenne characteristic sign

A

Gower’s sign

75
Q

Duchenne Muscular dystrophy

Gower’s sign

A

Difficulty standing up in young boys.
Get support from the legs and hunch to get support to stand up. Like old people

76
Q

X linked recessive disorders

Fragile X syndrome Sx

A
  • Large prominent ears
  • Broad forehead
  • Elongated face
  • Strabismus
  • high arched palate
  • hyperextensible joints
  • hand calluses
  • Pectus excavatum
  • Hypotonia
  • soft, fleshy skin
  • Enlarged testicles
  • flat feet
77
Q

Fragile X syndrome

Cardiac abnormality

A

Mitral valve prolapse

78
Q

Fragile X syndrome

Has Sx similar to Marfans (T/F)

A

True
* High arched palate
* Flat feet
* hyperextensible joints
* Pectus excavatum

79
Q

Fragile X syndrome

Muscle tone

A

Hypotonia

80
Q

Fragile X syndrome

Testicular volume atrophied (T/F)

A

False
Enlarged testicles

81
Q

Commonest cause for genetic mental retardation

A

Down Syndrome

82
Q

2nd most common cause for mental retardation

A

Fragile X syndrome

83
Q

Fragile X syndrome

Type of education

A

will need special schools.

84
Q

Hemophilia

Sx

A
  • Easy bruising
  • hemarthrosis
  • GI hemorrhage, ICH high risk
85
Q

Hemophilia

Mx

A
  • Factor VIII administration
  • Good dental hygiene
  • Good nutrition
  • Avoid injury and meals that promote bleeding