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Flashcards in Genetics Deck (154)
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1
Q

Pleiotropy meaning

A

Genes that gave more than one discernible effect on the phenotype for example CFTR, Marfans, osteogenesis imperfecta

2
Q

Alpert syndrome gene and inheritance pattern

A

FGFR2 (fibroblast growth factor receptor 2) AD

3
Q

Two examples of micro deletions

A

22q11 and Williams

4
Q

X linked dominant disorder

A

Incontinetia pigmenti

Other x linked recessive fragile x on FMR1 gene, haemophilia, duchenne and Becker

5
Q

Autosomal dominant - name five

A
Noonan
Charge
Alagille
NF 1
Marfan
Ehlers danlos 
Stickler 
Achondroplasia
Myotonic dystrophy
TS
Cornelia de Lange
6
Q

Limit of microarray

A

Misses balanced translocation

7
Q

CHARGE

A
Coloboma 
Heart
Atresia of choanae 
Retardation growth or mentation
Genital abnormalities
Ear abnormalities

CHD7 gene

Ddx kabuki and retinoic embropathy

8
Q

Heteroplasmy

A

The presence of both normal and mutation carrying mitochondrial DNA in a cell

9
Q

Aneuploidy caused by

A

Failure of homologous chromosomes to separate in anaphase I, failure of sister chromatids to separate at meiosis II

10
Q

Alagille inheritance

A

AD but 70% de novo (JAG1 gene chr 20p12)

<1% NOTCH2

11
Q

Ataxia telangiectasia clinically

A

Ataxia
Telangiectasia
Dev delay
Immunodeficiency

12
Q

Wiskott Aldrich clinically

A

Symptoms:
Petechiae (microthrombocytopenia)
Eczema
Immunodeficiency - Chronic draining ears (sinopulm infections)

Ix:
low immunoglobulin M (IgM) and immunoglobulin G (IgG) levels, normal-to-high immunoglobulin A (IgA) and immunoglobulin E (IgE) levels
No response to vaccine
Gene test WAS gene making WAS protein or WASP

XL (male 1-10 per million males)

13
Q

Badder-biedl

A
AR variable 
Short and fat
Retinitis pigmentosa 
Polydactyly 
Hypogonadism 
ID
14
Q

Beckwith-wiedemann

A
Disorder of imprinted gene 11p15 Overexpression IGF2 
Overgrowth, organomegally, omphalocoele
Hypoglycaemia
Ear crease and pits
Tumours
15
Q

Cornelia de lange

A
IUgR
Mono brow
Severe ID
Limb abnormalities
Cardiac
Gut malrotation
Self harm behaviour
16
Q

Most common thing associated 15% downs

A

Coeliac

Can have transient myeloprolif at birth (normalises by 2m)

17
Q

Noonan syndrome clinically

A

PS (ASD, HOCM)
Short
Web neck and triangular face, Epicanthus with slanted eyes, ptosis, low set ear, mild low IQ
Small testes and delayed puberty

18
Q

Stickler and Marshall due to..

A

Type 2 collages defect

19
Q

Smith lemil opitz due to

A
Defect in cholesterol metabolism elevated 7-dehydrocholesterol AR DHCR7 gene
Microcephalic, ambiguous genitalia males
Micrognathia 
Anteverted nostrils
Adrenal insuf 
Syndactyly 
Severe ID
Tx: cholesterol
20
Q

VACTERAL

A
Vertebral
Anal atresia
Cardiac
TOF
EA
Renal
Limb
21
Q

Velocardiofacial (22q11)

A

22q11 deletion (TBX1 and COMT)
1/4000
Sporadic (7% inherited AD)
Cleft palate with bifid uvula
VSD, conotruncal, commonly interrupted aortic arch B
Long face hypotonic with bulbous tip broad nose

22
Q

Williams

A

AD, 20 gene deletion on chr 7
FiSH (microdeletion)
Prominent lips, fat around eyes, big ears, blue eyes, stellate pattern on iris, elfin facies hypercalcaemia in infancy (resolves)
cocktail personality
Short stature and FTT
Cardiac abnormalities
– Supravalvar aortic stenosis 50%
–Peripheral pulmonary stenosis 27%
Intellectual disability ~100%
anxiety

23
Q

Zellweger

A
Peroxisomal disorder
Hypotonia
Absent reflexes 
Hearing and visual loss
Seizures
High forehead, large fontanell
Hepatomegally 
Die infancy no Rx
24
Q

Aneuploidy

A

Wrong no. Chromosomes

25
Q

Haplotype

A

Group of nearby or closely linked genes or alleles on chromosome that are inherited together

26
Q

DNA helixase job

A

Denaturation , separation of strands

27
Q

Southern vs northern blot

A

Southern DNA and northern RNA

28
Q

Most common congenital condition

A

Bilateral hearing impairment

29
Q

Cause of symptoms in female with x linked disorder

A

Lyonisation

30
Q

Sickle cell and thalassaemia inheritance

A

AR

31
Q

First cousins share how much genetic material

A

1/8th

32
Q

Risk sibling with autism

A

20%

33
Q

Allergy if one parent or two first degree relatives

A

50%

75%

34
Q

Diabetes if one first degree

A

5%

35
Q

Sibling with CHD

A

One first degree 2.5% or two is 20-30%

36
Q

Three AR conditions

A

Smith lemli opitz
Ataxia telangiectasia
Mucopolysaccharidoses

37
Q

Costello syndrome

A
New AD
FTT
Hand wrist position
Cardiac abn
10-15% risk cancer
38
Q

Cardiofaciocutaneous syndrome

A
New AD
HCMO, PS
Tall forehead, sparse fine curly hair
FTT
Sz
DD
39
Q

Fragile x related

A

Fragile x tremor ataxia syndrome (adults) and premature ovarian insufficiency

40
Q

PWS test

A

DNA methylation studies

41
Q

Trinucleotide repeat d/o

A
Fragile x (CGG)
Myotonic dystrophy (CTG)
Friederich ataxia (GAA)
42
Q

AD inheritance

A

Parent of affected person usually affected
Either sex and transmitted by either
50% chance offspring affected

43
Q

AR

A

Affected person usually carrier parents not affected
Affects either sex
25% risk affected child and 2/3rds siblings are carriers

44
Q

Allergic heterogeneity means

A

Many different types of mutations in a gene can result in same disorder

45
Q

Locus heterogeneity

A

Mutations in many different genes can result in same disorder (such as long QT)

46
Q

Example of incomplete penetrate and variable expressively

A
Incomplete penetrate (familial retinoblastoma)
Variable expression (Marfans)
47
Q

Heteroplasmy means

A

Presence of both normal and mutation carrying mitochondrial DNA in a cell

48
Q

How much of our genome codes protein

A

2%

49
Q

Missense and nonsense mutations

A

Missense alter coding sequence

Nonsense insert truncating codon

50
Q

Allelic heterogeneity

A

Causation of a disease phenotype from a variety of different genotype

51
Q

Germ line mosaicism example

A

Osteogenesis imperfecta

52
Q

Inactivation of one X chromosome happens when

A

About 2 weeks after fertilisation (starting at inactivation centre then spreading along chromosome)

53
Q

Example of mitochondrial disorders

A

MELAS (mitochondrial encephalopathy stroke like episodes and lactic acidosis)
Leigh
Pearson syndrome

54
Q

Balanced robertsonian translocation in downs recurrence

A

Father (1-2%)

Mother (10%-15%)

55
Q

Trisomy 13 patau syndrome

A

Cleft
Posterior polydactyly limbs
Holoprosencephaly

56
Q

Recurrence risk T13 and T18

A

1%

57
Q

Incontinentia pigmenti signs

A
Abortions
Dentition
Sz
Hair
Dev delay
58
Q

Ichthyosis skin

A

Fish scale

59
Q

Sturge Weber

A
Leptomeningeal angiomyolipomas
Urgent ophthalmology (glaucoma)
60
Q

Kasabach-Merritt

A
Kaposiform haemangioendotheliomas or tufted angiomas 
Thrombocytopenia and coagulopathy
Fibrin consumption
Anaemia
Up to 50% die without Tx (tx sirolimus)
(Not infantile haemangioma)
61
Q

Waardenburg

A

Hearing
Different coloured eyes
White forelock
Broad nose

62
Q

PHACE syndrome

A
Post fossa malformation 
Haemangioma
Arterial anomalies
Cv anomaly 
Eye anomaly
63
Q

Number of ribs in trisomy 21

A

11

64
Q

Williams syndrome 90% have which deletion

A

7q11.23

65
Q

CHD in Noonan

A

Pulm stenosis 50%

Hypertrophic cardiomyopathy 20%

66
Q

Cyanosed trisomy 21 has

A

TOF

67
Q

D TGA related to genetic syndrome

A

Rarely

68
Q

Situs inversus

A

Assoc dextrocadia and L-TGA (3-5%)

20% have kartageners

69
Q

Left atrial isomerism and right ?spleen

A

Polysplenia (multiple small non functioning) in left and asplenia in right

70
Q

Potters sequence

A

From oligohydramnios - pulm hypoplasia, cranial and facial abnormalities and clubbed feet
ARPKD can cause it (NO cysts in kidney)

71
Q

Tendon xanthomas indicate

A

Familial hypercholesterolaemia or familial defective apoprotein B100

72
Q

High what blood test in ataxia telegectasia?

A

Alpha feto protein

73
Q

Leukocyte adhesion def type 1 presentation

A

Delayed umbilical cord separation and sepsis

74
Q

Achondroplasia is a conical diagnosis but gene test is for..

A

99% of individuals with
achondroplasia have an amino acid substitution at position 380 (Gly380Arg) in the
FGFR3 gen

75
Q

Bilateral ear pits could be from what syndrome

A

branchio-oto-renal
(BOR) syndrome. This autosomal dominant disorder caused by mutations in EYA1 is
associated with preauricular pits (70%-80%), branchial cysts or fistulas (30%-60%), and
structural renal anomalies (12%-20%). Therefore, renal ultrasonography is recommended
in light of the other 2 clinical findings. In addition to these features, individuals with
BOR syndrome may have other external ear malformations, and at least 75% have some degree of hearing loss

76
Q

Achondroplasia inheritance and intelligence

A

Normal intelligence

Often sporadic and AD

77
Q

Infant ashkani Jewish normal at birth then progressive hypotonia, inattentiveness, an exaggerated startle response, evidence of visual dysfunction, and cherry-red spots on retinal examination has?

Cherry rest spots also seen in

A

Tay-sachs

cherry-red spots are seen in many lipid
storage disorders, including GM1 gangliosidosis, Sandhoff disease, some of the mucopolysaccharidoses, Niemann-Pick disease, and mucolipidoses

78
Q

Allelic heterogeneity –

Locus heterogeneity –

A

Allelic heterogeneity – Many different types of mutations in a gene can result in the same
disorder
e.g most disorders; exceptions: Huntington disease
• Locus heterogeneity – mutations in many different genes can result in the same disorder
e.g long QT syndrome (at least 7 different genes)

79
Q

Variable expression but complete penetrative in what condition

A

22q11

80
Q

Angelmans syndrome

A

AS: hypertonic, profound mental retardation, seizures, frequent smiling and laughing, growth retardatio, widely spaced teeth

81
Q

Turners newborn

A

Web neck, puffy hands and feet and cardiac

82
Q

Dental pits and confetti skin lesions seen in? (Minor criteria)

A

TS

83
Q

Ungal fibromas, hypomelanotic lesions, facial adenomas age in TS

A

Hypo lesions at birth
Facial ‘acne’ 3-15y
Ungal fibromas after puberty

84
Q

SEGA seen in what and how to manage

A

SEGA are growths into ventricles
Slow
Not responsive to chemo or radio (resect and manage hydrocephalus)
MTOR inhibitors

85
Q

Cafe au Lai spots in which syndromes

A

NF 1 and 2
McCune Albright (jagged edge rarely cross midline)
Legius syndrome
LEOPARD syndrome

Watson, bloom, Russell-Silver

86
Q

Short forth metacarpal due to?

A

Turners
FAS
Pseudohypoparathyroidism

Gorlin
Homocysteinuria
Sickle cell infarct
Leri‐Weill dyschondrosteosis

87
Q

Haploinsufficiency of the SHOX gene is also responsible for short stature in Turner syndrome.

A

Turner syndrome. sHOX gene has dose effect

88
Q

Mother affected and child has vomiting, abdominal pain, extreme tiredness (fatigue), muscle weakness, and difficulty breathing. Also involuntary muscle spasms (myoclonus), impaired muscle coordination (ataxia), hearing loss, heart and kidney problems, diabetes, and hormonal imbalances.

A

MELAS

89
Q

What syndrome is characterized by a progressive loss of vision and hearing, a form of heart disease that enlarges and weakens the heart muscle (dilated cardiomyopathy), obesity, type 2 diabetes mellitus (the most common form of diabetes), and short stature.

A

Alström syndrome

90
Q

Present with retinitis pigmentosa and deafness

A

Usher syndrome

91
Q

What syndrome?

Affected individuals can exhibit growth retardation, short stature, premature graying of hair, hair loss, wrinkling, prematurely aged faces, beaked noses, skin atrophy (wasting away) with scleroderma-like lesions, loss of fat tissues, abnormal fat deposition leading to thin legs and arms, and severe ulcerations around the Achilles tendon and malleoli. Other signs include change in voice, making it weak, hoarse, or high-pitched; atrophy of gonads, leading to reduced fertility; bilateral cataracts (clouding of lens); premature arteriosclerosis (thickening and loss of elasticity of arteries); calcinosis (calcium deposits in blood vessels); atherosclerosis (blockage of blood vessels); type 2 diabetes; loss of bone mass; telangiectasia; and malignancies. In fact, the prevalence of rare cancers, such as meningiomas, are increased.

A

Werner syndrome

92
Q

Present with short stature, a skin rash that develops after exposure to the sun, and a greatly increased risk of cancer.

A

Bloom syndrome

93
Q

Screen for wilms in

A
WT1 deletions (11p13) = WAGR syndrome
• Wilms 50%, Aniridia (no iris) 100% (PAX6 del), GU, Retardation
• WT1 missense mutation = Denys‐Drash syndrome
• Nephropathy and intersex
• FWT1 (17q12‐q21)
94
Q

Gene for rett

A

MECP2

95
Q

Severe insulin resistance syndrome called

?
Presents with SGA, acanthosis nigracans, lipodystrophy, hairy ALL over and typical facial features

A

Donohue

96
Q

Biliary obstruction with large liver differential cause

A

Choledochal cyst

97
Q

Hearing loss and goitre syndrome

A

Pendred syndrome

98
Q

Trichorrhexia invaginata (bamboo hair), severe eczema, FTT, recurrent infections causes by

A

Netherton syndrome

99
Q

Impaired immunity, thrombocytopenia and eczema from what syndrome

A

Wiskott-Aldrich

100
Q

Wilsons gene

A

ATP7B

101
Q

Alpha 1 antitrypsin def gene

A

SERPINA1

102
Q

Progressive familial intrahepatic cholestasis 1 gene

A

PFAC1 (FIC def) chr 18q12

103
Q

Excessive physical growth is what syndrome

A

Sotos

104
Q

Pakinsonian features and tremors

MRI findings giant panda (abnormal signal in globes pallidus, puts men, substanstia nigra)

A

Wilson’s disease

105
Q

What does DNA and RNA polymerase do

A

Synthesise rna and DNA

106
Q

Syndromes associated with histologicsl absence of meissners and auerbachs plexsus with high achetylcholinesterase

A

Downs, Joubert, smith-lemli-opitz, NF, Ondine’s curse

107
Q

Gene mutations in hereditary pancreatitis (chronic in children often from genetic mutations)

A

SPiNk 1
CTFR
cTRC

108
Q

Holoprosencephaly is associated with what cardiac abnormality

A

AOLCA

109
Q

Marfanoid habitus differential

A
Marfans
mASS
Homocysteinuria (lens down and out instead of UP in marfans)
Stickler
Shprintzen goldberg
110
Q

Glaucoma associated with (3)

A

Rubella
Lowe syndrome
Sturge Weber

111
Q

Alopecia arrests associated with? What positive test

A

Atopy, autoimmune, Fhx

Positive pull test and nail changes

112
Q

Differential to gum bleed (presents like vwd)

A

Bernard-soulier syndrome (defect in glycoproteins Ib the receptor for vwf)

113
Q

Platelet transfusion is matched with

A

The ABO and rhesus (especially if negative)

I.e if patient A- use A- platelets
Irradiated preferred
Can be from single or pooled - no difference in reaction rate

114
Q

G6PD inheritance

A

XL recessive

115
Q

Subtle triangle face and small eyes and thumb/radial abnormality dysmorphisms of what

A

Fanconi

116
Q

Beak nose and broad thumb in what

A

Rubinstein-taybi

117
Q

What immune marker low in prem vs term

A

Immunoglobulins

118
Q

What following observations regarding a rare disorder would provide the best evidence of
autosomal dominant inheritance?

A

Father and son affected

119
Q

Mutation in DMd

A

Deletion of several exams in Dystrophin gene

120
Q

Child with short stature, moderate to severe intellectual disability, distinctive facial features, and broad thumbs and first toes. Additional features of the disorder can include eye abnormalities, heart and kidney defects, dental problems, and obesity.

A

Rubinstein-Taybi syndrome

CREBBP gene

121
Q

Child with light skin, silvery hair, recurrent infections (immune deficiency) and easy bleeding

Also visual problems/clumsiness (peripheral neuropathies)

A

Chediak-Higashi syndrome

122
Q

3 year old child under 10th centime growth (short), microcephalic, dangling thumbs, dislocated hips, rocker bottom feet, cafe au lait

Anaemia or aplastic anaemia

A

Fanconi anaemia

123
Q

Short girl always consider

A

Karyotype for turners

124
Q

Presents with imperforate anus, renal, polydactyly, syndactyly and hypothalamic hamartoma

A

Pallister hall

125
Q

Gene associated with ARPKD salt and pepper appearance kidney on USS)

A

PKHD1

126
Q

Presents with acidic stools containing sugar and defect in SGLT1 called

A

Glucose-galactose malabsorption

127
Q

Present with short boy rickets with low phosphate and normal vitamin d level and high ALP
What genetic test to confirm diagnosis?

A

PHEX

X-linked hypophosphatemia (inability transporter to get to apical membrane to reabsorb phosphate in kidney)

128
Q

LEOPARD syndrome

A

L – lentigines (multiple brown-black spots on the skin)
E – electrocardiographic (ECG) conduction defects
O – ocular hypertelorism
P – pulmonary stenosis
A – abnormalities of genitals
R – retarded growth resulting in short stature
D – deafness or hearing loss due to inner ear malfunction

129
Q

CTRC gene associated with

A

Hereditary pancreatitis

130
Q

Congenital nephrotic syndrome NPhS1 and 2 code for

A

Nephrin and podocin

131
Q

What syndrome?

Red skin, bamboo hair, atopy

A

Nethertons syndrome

132
Q

Persistent tachypnoea infant syndrome

A

Neuroendocrine cell hyperplasia of infancy

133
Q

Which disease characterized by (nervous system involvement) hypotonia, peripheral neuropathy, ataxia, retinitis pigmentosa (vision), hearing

(Liver and kidneys)

A
AR perixsomal d/o
Refsum disease (mild form of zellweger spectrum, zellweger severe form, adrenoleukodystrophy intermediate and refsum mild)
134
Q

Blue eyes with stellate pattern iris in

A

Williams

135
Q

Dural ectasia causes (3)

A

Marfans (major criteria and 60% have)
NF
Osteogenesis imperfecta

136
Q

Mnemonic NOONANS

A

Neurodevelopmental problems, neuromuscular (hypotonia –
floppy strong, joint hyperextensibility), neurosurgical (Arnold-
Chiari type I).
Obstructive heart lesions: RVOT (pulmonary valve), LVOT
(HCM). Other: ASD, VSD, TOF, coarctation, branch pulmonary
artery stenosis.
Ocular abnormalities: strabismus, refractive errors, amblyopia,
nystagmus, hypertelorism, epicanthic folds, droopy eyelids,
vivid blue or blue green irises.
Neoplasia risk: JMML, myeloproliferative disorders, multiple
giant cell lesion syndrome (granulmoas and joint and bone
anomalies), hepatosplenomegaly (subclinical myelodysplasia).
Abnormal coagulation, abnormal lymphatics (lymphedema and
lymphangiectasia).
Neck webbing with low set and posteriorly rotated ears,
nipples low set, nephrological anomalies (duplex, renal
hypoplasia).
Sternal deformity (superior carinatum, inferior excavatum),
short stature, secondary sexual characteristics (delayed
puberty, cryptorchidism), skin findings (café au lait etc)

137
Q

Williams hypercalcaemia mnemonic

A

William’s syndrome.
 Intellectual impairment (IQ average 50-60). Impaired vision.
 Low tone. Low pitched or hoarse voice, vocal cord paralysis.
 Lax joints. Loquacious, over friendly, excessively empathetic.
 Impaired feeding (difficulty with food textures, vomiting).
 ADHD symptomatology. Anxiety.
 Mitral valve prolapse.
 Supravalvular aortic stenosis. Spine (scoliosis, kyphosis).
Sternum (excavatum).
 HYpercalcemia, hyperclaciuria, hypertension.
 Peripheral pulmonary artery stenosis. Puberty early (not
precocious).
 Elastin arteriopathy (aortic insufficiency, stenosis of
mesenteric arteries). Endocrine (hypothyroidism, IDDM). Elfin
face.
 Renal anomalies (nephrocalcinosis, pelvic kidney).
 Chronic otitis media. Characteristic personality.
 Audiological problems (high frequency sensorineural hearing
loss, hyperacusis).
 Linear growth failure.
 Cognitive (poor visuospatial construction).
 Appearance (broad brow, bitemporal narrowness, medial
eyebrow flare, short palpebral fissures, epicanthic folds, blue
stellate iris, short nose, full nasal tip, full cheeks, malar
hypoplasia, long philtrum, full lips, wide mouth, small jaw,
prominent earlobes).
 Eyes (hypotelorism, strabismus, amblyopia, refractive errors).
 Maloclussion, microdentia, enamel hypoplasia, widely spaced
teeth, missing teeth.
 Intestinal problems (constipation, diverticulosis, coeliac
disease).
 Abdominal pain (reflux oesophagitis, cholelethiasis,
diverticulitis, ischaemic bowel disease).

138
Q

Gene involved in zellweger spectrum

A

Approximately 68 percent of individuals with a Zellweger spectrum disorder have a mutation in the peroxisome biogenesis factor 1 (PEX1) gene located on the long arm of chromosome 7 (7q21-22).
Peroxisomes in cytoplasm required to metabolise VLCFA thus these increased

139
Q

GP1B defect with giant platelets and bleeding is

A

Bernard-soulier syndrome

140
Q

Syndromes associated with craniosynostosis

A

Crouzon, Apert, Carpenter, Chotzen, Pfeiffer

141
Q

BWS risk wilms

A

5-10%

142
Q

On penetrence is?

A

When genetically Have both alleles but not the phenotype

143
Q

The polymerase chain reaction (PCR) requires the use of a DNA polymerase. The action of the DNA
polymerase is best described as:
A. allowing primers to affix to the single strands.
B. causing double-stranded DNA to become singled-stranded.
C. extending the primers once they are affixed to the single strands.
D. inducing fluorescence of DNA.
E. splitting the single strand and the extended primer.

A

C

144
Q

Hypotrophic hypogonadism, anosmia, renal, facial =

A

Kallmans syndrome

145
Q

Asymmetric face (one side very abnormal) called?

A

Goldenhar or occulo-auricle-vertebral syndrome

146
Q

Self mutilation and lip biting in?

A

Lesch-nyhan

147
Q

RB1 and RET genetic defects of..

A

Retinoblastoma and MEN

148
Q

IPEX syndrome

A

Immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome

149
Q

Infertile, bronchiectasis and dextrocardia

A

Kartagener syndrome (PCD)

150
Q

Hair has pili tortilla and fractures along hair shaft? Diagnosis

A

Menkes

151
Q

Kabuki syndrome gene

A

MLL2

152
Q

Long QT and hearing impairment called

A

Jervell and Lange-Nielsen syndrome

153
Q

Long QT 1-3 genetics

A

Long QT1: KCNQ1
Long QT2: KCNH2
Long QT3: SCN5A

154
Q

Fanconi anaemia mnemonic

A

FANCONI

Fragile chromosomes/ fluid in brain
Abnormal kidney
Not tall
Cafe Aui Lai
Odd eyes and ears
No children
Increased cancer risk (AML) 10-30%