Genetics Flashcards

1
Q

cause of down syndrome

A

meiotic non disjunction most common during oogenesis (94%)
maternal nondisjunction is cause in 88%
47XX/XY + 21

unbalanced robertsonian translocation (5%) -> family history

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2
Q

what are the screening bloods tests offered for downs syndrome

A

10-14 weeks: beta hcg + pregnancy associated plasma protein + ultrasound scan +maternal age
= gives estimated risk of downs syndrome (picks up 84%)

14-20 weeks: beta hcg, alpha fetoprotein, inhibin A and unconjugated oestradiol
calculates risk of downs with maternal age

if risk of downs more than 1 in 150 -> offered diagnostic test -> CVS (10-13 weeks gestation) or amniocentesis (16 -20 weeks). both have 1% risk of miscarriage

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3
Q

dysmorphic features of downs syndrome

A
  • epicanthic folds
  • flat nasal bridge
  • single palmer crease
  • large sandal gap
  • low set small ears
  • brushfiedl iris spots
  • short stature
  • protruding tongue
  • short neck
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4
Q

Other features and conditions associated with downs syndrome

A
  • ears: otitis media with effusion
  • eyes: strabismus, nystagmus, cataracts
  • heart: AVSD, VSD
    -CNS: hypotonia, developmental delay, alzheimers risk
  • hypothyroid
  • haem: ALL. AML
  • Gastro: GORD, duodenal atresia, coeliac, pyloric stenosis, hirschsprungs diosease, meckels diverticulum, tracheo-oesophageal atresia
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5
Q

How to test for downs syndrome

A

QF-PCR for chromosome 21 ** + karyotype

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6
Q

what are the features of edwards syndrome (trisomy 18)

A
  • low set ears
  • prominent occiput
  • small mouth and chin
  • cleft palate
  • overlapping fingers and clenched fists
  • small birth weight and IUGR
  • rocker bottom feet
  • ASD, VSD, PDA
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7
Q

What are the features of patau syndrome (trisomy 13)

A
  • cleft lip and palate
  • small eyes
  • polydactyly
  • structural defect of brain
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8
Q

how do you diagnose turners sydnrome

A

Karyotype

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9
Q

what are the physical features of turners syndrome

A
  • wide spaced nipples
  • short stature
    -webbed short neck
  • low hairline
  • scoliosis
  • non pitting lymphoedema
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10
Q

which conditions is Turners syndrome associated with?

A
  • coarction of aorta, bicuspid valve
  • hypothyroidism
  • gonadal dysgenesis : premature ovarian failure and delayed puberty
  • horseshoe kidney, renal aplasia, duplicated ureters
  • recurrent otitis media
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11
Q

How can you manage Turners syndrome?

A
  1. growth hormone
  2. oestrogen replacement therapy
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12
Q

what is the cause of Klinefelters syndrome

A

47 XXY
non disjunction in stage 1 of meiosis causes additional Y chromosome and forms barrs body

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13
Q

How do Klinefelters syndrome present at puberty?

A
  • poor growth
  • small testes
  • gynaecomastia
  • truncal obesity
  • tall stature
  • mild development and behavioural problems
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14
Q

Which conditions is Klinefelters syndrome associated with?

A

breast cancer
hypothyroid
mitral valve prolapse
osteoporosis
autoimmune disease
leukaemias

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15
Q

management of Klinefelters

A

testosterone

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16
Q

Genetic mutation in William syndrome

A

microdeletion of chromosome 7 (7q11.23)

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17
Q

diagnosis of william syndrome

A

FISH or chromosomal miroarray

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18
Q

features of william syndrome

A
  • broad forehead
  • wide mouth and prominent upper lip
  • supraclavicular aortic stenosis + pulmonary artery stenosis
  • hypercalcaemia
  • learning difficultues but strong social skills
  • affinity for music
  • outgoing personality
  • ## blue iris and blond hair
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19
Q

genetic cause of DiGeorge syndrome?

A

22q11 microdeletion syndrome (reduction in T box transcription factor 1) and disrupts development in the 3rd and 4th pharyngeal arch
defect in neural crest cells

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20
Q

clinical features of DiGeorge syndrome

A

C - cardiac - ToF, interrupted aortic arch
A- abnormal facies e.g. narrow palpebral fissures, high broad nasal bridge, short philtrum
T- thymic aplasia - immunodeficiency
C- cleft palate
H- hypocalcaemia and hypoparathyroidism
22

  • scoliosis, behavioural disorders, poor growth, renal agenesis
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21
Q

inheritance of noonan syndrome

A

autosomal dominant

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22
Q

genetic cause of noonan syndrome

A

mutation in PTPN11 gene on chromosome 12 ** or mutation in SOl1 gene on chromosome 2

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23
Q

clinical features of noonan syndrome

A
  • short stature
  • triangular shaped face, down slanting parapebral fissures, short webbed neck, low set ears
  • strabismus, ptosis
  • pectus excavatum, wide spaced nipples
  • heart : pulmonary valve stenosis, hypertrophic cardiomyopathy
  • VWF disease, thrombocytopenia
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23
Q

genetic cause of Tay sachs

A

frameshift mutation in HEXA gene on 15q23-q24 causing failure to break down GM2-GANGLIOSIDE - which then accumulates in neurones and causes neurodegeneration

decreased lysosomal hydrolysis

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24
Q

inheritance of Tay sachs disease

A

autosomal recessive

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25
Q

presentation of tay sachs disease at 3-6 months old

A

myoclonic jerks, exaggerated startle reflex

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26
Q

presentation of tay sachs disease at 6-10 months old

A

developmental regression, hypotonia, seizures

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27
Q

presentation of tay sachs disease over 5 y/o

A

confusion, ataxia, macular cherry red spot, death secondary to resp failure

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28
Q

how is tay sachs disease diagnosed

A

enzyme activity of hexa A

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29
Q

inheritance of phenylketonuria

A

autosomal recessive

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30
Q

genetic cause of phenylketonuria

A

phenylalanie hydroxylase deficiency causing phenylalanine (inhibits cerebral uptake of tyrosine and tryptophan) to accumulate in brain

can be metabolised to phenyl ketones
tetrohydrobiopterin cofactor for conversion of phenlylalanine to tyrosine and also implicated in the disease

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31
Q

clinical features of phenylketonuria

A
  • vomiting
  • musty odour
  • seizures, spasticity, tremors
  • hyperactivity, autism, purposeless hand movements
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32
Q

facial features of phenylketonuria

A

fair hair, eyes, hair
microcephaly
wide spaced teeth
prominent maxilla
enamel hypoplasia

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33
Q

phenylketonuria management

A
  1. phenylketonuria restricted diet - XP anologue LCP milk (phenylalanine free milk)
  2. large amino acids e.g. tryptophan, tyrosine
  3. tetrahydrobiotin
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34
Q

inheritance of fragile X syndrome

A

X linked dominant

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35
Q

genetic cause of fragile X syndrome

A

repeat expansion disorder of CGG repeats on FRM1 gene

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36
Q

clinical features of fragile X syndrome

A
  • developmental delay, learning difficulties (most common cause in boys), ADHD
  • recurrent otitis media
  • high forehead
  • large jaw
  • long ears
  • narrow elongated face
  • hyper extendable finger joints
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37
Q

risks for women with fragile X

A

more common in women
50% risk of premature ovarian failure or early menopause

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38
Q

inheritance of Rett syndrome

A

X linked dominant or sporadic mutation in MECP2 gene

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39
Q

Clinical features of Rett syndrome

A

child born healthy and then developmental regression around 6-18 months…
- involuntary hand movements e.g clapping, hand wringing
- apraxia
- teeth grinding
- dysphagia, poor weight gain, feeding difficulty
- involuntary behaviour e.g. laughing
- hypertonia, spasms, seizures, vacant speels
- aspiration pneumonia

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40
Q

genetic inheritance of Prader willi syndrome

A

Imprinting: deletion occurs in paternal chromosome 15q11-13 so child lacks paternal copy of this region

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41
Q

presentation of prader willi syndrome

A
  1. severe neonatal hypotonia
  2. difficulties feeding in newborn stage
  3. obesity and short stature
  4. hypogonadism
  5. behavioural difficulties - tantrums, temper
  6. narrow forehead, almond eyes, thin upper lip, small hands and feet
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42
Q

complications of prader willi syndrome

A
  1. hypothyroid
  2. learning difficulties
  3. OSA
  4. osteoporosis
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43
Q

diagnosis of prader willi syndrome

A

DNA methylation specific testing or FISH

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44
Q

Management of prader willi syndrome

A

growth hormone therapy

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45
Q

inheritance of angelman syndrome

A

failure to inherit a functioning maternal copy of chromosome region 15q11-13
or paternal uniparentaldisomy of chromosome 15

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46
Q

features of angelman syndrome

A

ataxia and tremor
epilepsy
‘happy children’- smiling and laughter
severe developmental delay
microcephaly

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47
Q

inheritance of marfan syndrome

A

autosomal dominant

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48
Q

genetic cause of marfans

A

missense mutation on chromosome 15q21 which codes for fibrillin 1 which is needed for cellular microfibrins and regulation of TGF-BETA

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49
Q

physical features of marfans disease

A
  • tall stature with long limbs
  • scoliosis
  • pectus excavatum
  • down slanting palpebral fissures
  • malar hypoplasia
  • high narrow arched palate
  • striae
  • myopia and ectopia lentis
  • risk of spontaneous pneumothorax
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50
Q

cardiac conditions associated with marfans

A

aortic root dilatation
mitral valve prolapse (pan systolic murmur)
aortic dissection (give beta blockers and ACE-I)

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51
Q

marfans diagnosis

A

2010 revised ghent nosology clinical criteria and molecular gene testing

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52
Q

inheritance of incontinenti pigmenti

A

X linked dominant

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53
Q

genetic cause of incontinenti pigmenti

A

mutation in IKBKG gene

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54
Q

clinical features of incontinenti pigmenti

A
  • skin rash vesicular /blisters -> watery papular lesions -> hyperpigmented ‘marbled tablecloth’ -> atrophic and hair loss
  • dental abnormalities
  • seizures
  • developmental delay
    -females

(males miscarry)

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55
Q

inheritance of fanconi anaemia

A

autosomal recessive

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56
Q

features of fanconi anaemia

A
  1. bone marrow failure
  2. congenital abnormalities e.g. cafe au lait macules, hypoplasia of thumb
  3. increased cancer risk
  4. developmental; delay and short stature, hypogonadism, dysplastic limbs
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57
Q

diagnosis of fanconi anaemia

A

chromosome breakage test

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58
Q

management of fanconi anaemia

A

stem cell transplant

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59
Q

inheritance of galactosaemia

A

autosomal recessive

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60
Q

genetic cause of galactosaemia

A

mutation and deficiency in GALT enzyme so inability to metabolise lactose and galactose
causes accumulation of gal-1-p and UDP

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61
Q

features of galactosaemia

A
  1. early jaundice
  2. hepatomegaly
  3. oil drop cataracts
  4. e.coli infections
  5. developmental delay and seizures
  6. feeding difficulties and faltering growth
  7. diarrhoea
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62
Q

diagnosis of galactosaemia

A

quantitative assay of RBC GALT activity (reduced) and genetic testing

high GAL-1LP levels
high galactose levels in blood and urine
high galacitol

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63
Q

management of galactosaemia

A

dietary modification - lactose and galactose free diet
casein hydrolysate formula for babies

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64
Q

features of CHARGE syndrome

A

C- coloboma
H- herat defects
A- choanal atresia
R- retardation of growth and development
G- genital abnormalities
E - ear abnormalities - absent/ semi circular ear canals

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65
Q

genetic cause of beckwith wiedeman syndrome

A

abnormality of chromosome 11p15 (microdeletion)

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66
Q

clinical features of beckwith wiedeman syndrome

A
  1. macrosomia
  2. macroglossia
  3. ear pits
  4. increased risk of malignancies e.g. wilms tumour, hepatoblastoma
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67
Q

surveillance of beckwith wiedeman syndrome

A

abdo USS every 3 months until age of 8
serum alpha fetoprotein level every 2-3 months until age of 4

68
Q

inheritance of duchenne muscular dystrophy

A

X linked recessive
(females asymptomatic)

69
Q

genetic cause of duchenne muscular dystrophy

A

mutation in dystrophin gene so produce no dystrophin
(gonadal mosaicism worsens phenotype)

70
Q

presentation of duchenne muscular dystrophy

A

progressive proximal muscle weaknee
gowers sign (difficulty to stand from sitting)
trendelenburgs gait
by adolesence, require wheelcahir
dilated cardiomyopathy
resp failure

71
Q

diagnosis of Duchenne muscular dystrophy

A

creatinine kinase high
muscle biopsy - absent dystrophin

72
Q

inheritance of tuberous sclerosis

A

autosomal dominant

73
Q

genetic cause of tuberous sclerosis

A

most mutations on TSC2 gene on chromosome 16 ** which codes for tuberin or TSC1 gene for hamartin

—> FORMS HAMARTOMAS (organ malformations of hypertrophied abnormal mixture of cells)

——> leads to dysregulated mTOR (mammalian taaget of rapamycin)

74
Q

clinical dermatology features of tuberous sclerosis

A
  1. hypomelanotic macules
  2. ash leaf macules
  3. shagreen patches
  4. adenoma sebaceum (acne linke)
75
Q

clinical features of tuberous sclerosis

A
  1. retinal hamartomas
  2. dental fibromas
  3. cardiac rhabomyomas
  4. focal seizures + infantile spasms
  5. learning disability, ADHD, autism
  6. renal calculi
  7. cortical tubers and subependymal nodules
76
Q

inheritance of friedrichs ataxia

A

autosomal recessive

77
Q

genetic cause of friedrichs ataxia

A

defect in FXN gene (frataxin protein) - GAA repeat expansion in non coding region of gene coding for frataxin and causes excessive iron deposits in mitochondira

78
Q

presentation of friedrichs ataxia

A
  1. progressive ataxia
  2. normal intelligence
  3. absent deep tendon reflexes
  4. peripheral sensory neuopathy
  5. dysarthria
  6. progressive scliosis and kyphosis
  7. hypertrophic cardiomyopathy
  8. diabetes
  9. optic atrophy
79
Q

inheritance of neurofibromatosis type 1

A

autosomal dominant
50% DE NOVO mutations

80
Q

genetic cause of neurofibromatosis type 1

A

mutation on chromosome 17
NF1 gene encodes for neurofibrin. (tumour suppressor gene) -> decreased production of neurofibrin

81
Q

presentation of neurofibromatosis type 1

A
  1. cafe au lait spots
  2. anxillary freckling
  3. skeletal dysplasia
  4. neurofibroma
  5. lisch nodules (raised tan coloured hamartomas of iris)
  6. optic glioma
  7. hypertension- due to renal artery stenosis
  8. neuro abnormalities e.g. LD, seizures
82
Q

inheritance of cystinuria

A

autosomal recessive

83
Q

genetic cause of cystinuria

A

mutation in SLC3A1 gene on chromosome 2 and SLC7A9 gene on chromosome 19 - codes for transporter protein in proximal convulated tubule for amino acids - so excess urinary excretion of certain amino acids e.g. cystine, arginine, lysine, orthinine

84
Q

main complication of cystinuria

A

causes kidney stones !!! cystine crystallizes and forms stones !!! can result in CKD !!!

present with haematuria, flank pain, N&V, recurrent UTIs, incidental finding

85
Q

definitive diagnostic test of cystinuria

A

quantitative amino acid chromatography of urine (shows increased urine cystine levels)

86
Q

cystinuria management

A
  1. high fluid intake >3L a day
  2. alkalising urine agent - potassium citrate
  3. dietary Na restriction
87
Q

genetic cause of MCAD deficiency

A

mutation in ACADM gene which codes for MCAD leading to deficiency of enzyme so unable to metabolise medium chain fatty acids into energy
causes reduced hepatic ketogenesis

88
Q

when does medium chain acyl co-enzume A dehydrogenase deficiency present

A

presents in times of increased energy demands normally in infancy e.g. when ill, prolonged periods of fasting
individual can not produce enough energy from fat stores which causes hypoglycaemia and metabolic crisis

89
Q

presentation of MCAD deficiency

A

presents with at 2-3 months old:
1. hypoketotic hypoglycaemia
2. vomiting, lethargy, reduced GCS, hepatomegaly, seizures
3. recurrent infections

90
Q

diagnosis of MCAD deficiency

A

newborn screening !!!
measures acylcarnitine levels in blood spots and shows high C6-C10 species (esp C8 - otanolycarnitine)

91
Q

tests to do if suspect MACD deficiency

A
  1. glucose - low
  2. high ALT and deranged LFTs
  3. high ammonia
  4. high urate
  5. high C8 levels/ octanolycarnitine levels + high acyclcarnitine levels
  6. urinary amino acids
  7. ketones low
92
Q

management of MCAD deficiency

A
  1. avoidance of fasting and regular feeding
  2. low fat diet
  3. IV glucose in times of metabolic crisis
  4. L carnitine supplements
93
Q

inheritance of sickle cell anaemia

A

autosomal recessive

94
Q

genetic cause of sickle cell anaemia

A

point mutation at position 6 on beta globin gene (glutamine -> valine) which causes formation of HbS which is rigid and insoluble.

95
Q

pathophysiology of sickle cell

A

Hb S polymerises when in low oxygen tension and forms sickle cells.
sickle cells become trapped in microvasculature
causes thrombosis or ischaemia

96
Q

presentation of sickle cell

A

chronic haemolytic anaemia
jaundice
increase risk of encapsulated organisms e.g. salmonella, pneumococcus

97
Q

diagnosis of sickle cell

A

NEW BORN SCREENING
high performance liquid chromatography

98
Q

chronic management of sickle cell

A
  • folic acid
  • prophylactic abx
  • vaccinations
  • hydroxycarbamide - increases HbF levels and reduces painful episodes
  • crizanlizumab - monthly infusion, trial
99
Q

acute management of sickle cell

A
  1. analgesia - morphine
  2. hydration. IVF
  3. oxygen
  4. transfusion
  5. IV antibiotics
100
Q

inheritance of hereditary spherocytosis

A

autosomal dominant

101
Q

pathophysiology of hereditary spherocytosis

A
  1. inherited defect in genes that code for erythrocyte cytoskeleton e.g. spectrin
  2. loss of membrane surface causing sphering of RBCs
  3. impaired cell passage from splenic cords to sinuses and prone to haemolysis
102
Q

presentation of hereditary spherocytosis

A
  • jaundice
  • fatigue
  • chronic haemolytic anaemia
  • splenomegaly
  • abdo pain
  • gallstones
103
Q

investigations for hereditary spherocytosis

A
  1. FBC, reticulocyte count
  2. blood film - spherocytes and reticulocytosis
  3. LFT - unconjugated bilirubin increase
104
Q

inheritance of haemophilia

A

X linked recessive

105
Q

haemophilia A definition

A

deficiency of factor VIII
more common

106
Q

haemophilia b definition

A

deficiency of factor IX
vit K dependent

107
Q

presentation of haemophilia

A

haematoma at delivery
excessive bleeding
unexpected bleeding loss
excessive bruising
epistaxis
intracranial bleeding

108
Q

investigations for haemophilia

A

FBC - low haematocrit
prolonged APTT
factor VIII or IX reduced

109
Q

inheritance of G6PD deficiency

A

X linked recessived
missense mutations

110
Q

presentation of G6PD deficiency

A
  1. neonatal jaundice
  2. haemolytic anaemia
  3. drug sensitive haemolytic anaemia e.g. nitrofurantoin, quinine, aspirin, chloramphenicol
  4. favism - acute intracvascular haemolysis after ingestion of fava beans
111
Q

investigations for G6PD deficiency

A
  1. FBC
  2. rise in indirect bilirubin
  3. rise in LDH
  4. smear - heinz bodies, bite cells
112
Q

inheritance of cystic fibrosis

A

autosomal recessive

113
Q

genetic defect in CF

A

defective CFTR (cAMP dependent Cl channel) on chromosome 7
most frequent mutation F508 - class 2 mutation causing defective protein folding so cant reach apical membrane

114
Q

presentation of newborn with CF

A
  1. meconium ileus - vomiting, abdo distension, failure to pass mec
  2. prolonged neonatal jaundice
115
Q

presentation of infant with CF

A
  1. faltering growth
  2. recurrent resp infections, H influenza -> pseudomonas aeruginosa -> burkholderia
  3. wet cough
  4. malabsorption, steattohoea
116
Q

presentation older child with CF

A
  1. bronchiectasis
  2. rectal prolapse
  3. nasal polyp
  4. sinusitis
  5. inferity in males
  6. diabetes
  7. distal intestinal obstruction
117
Q

inheritance of primary ciliary dyskinesia

A

autosomal recessive

118
Q

pathophysiology of primary ciliary dyskinesia

A

defect in structure or funtion of ciliary proteins causing inefficacy of cilia - cilia beat frequency affected

119
Q

presentation of primary ciliary dyskinesia

A
  1. recurrent chest infections
  2. productive cough
  3. purulent nasal discharge
  4. chronic ear infections
120
Q

gold standard diagnostic test for primary ciliary dyskinesia

A

bronchial brush biospy and transmission electron microscopy

121
Q

what is kartagener syndrome

A
  1. ciliary dyskinesia
  2. sinus vertus
  3. dextrocardia
122
Q

inheritance of spinal muscular atrophy

A

autosomal recessive

123
Q

features of spinal muscular atrophy

A

gross motor delay
lower motor neurone pathology - reduced muscle tone, absent deep tendon reflexes

124
Q

diagnosis of spinal muscular atrophy

A

molecular genetic testing- most caused by deletion of exon 7 on SMN1 gene

125
Q

features of Pendred syndome

A

sensorineural deafness b/l - dilated vestibular aqueducts
goitre
vestibular dysfunction

126
Q

genetic cause of cri du chat

A

chromosome 5 p deletion

127
Q

features of cri du chat

A

high pitched cry
feeding difficulties
low birth weight
developmental delay
dysmorphic features - down ward slanting mouth, low seat ears, small head, flat nasal bridge

128
Q

features of foetal alcohol syndrome

A

thin vermillon border
smooth philtrum
short palpebral fissures
developmental delay
irritable

129
Q

triad of wiskott aldrich syndrome

A
  1. eczema
    2.thrombocytopenia
  2. recurrent bacterial infections

X linked recessive immunodeficiency disorder

130
Q

investigation for angelmans syndrome

A

DNA methylation testing

131
Q

1st test for global developmental delay

A

microarray
identify chromosome imbalance, microdeletions and micro duplications

132
Q

test for fragile X syndrome

A

FMR1 DNA anaylsis

133
Q

presentation of russel silver syndrome

A

IUGR
triangular facies
limb asymmetry
clinodactyly

134
Q

cause of myotonic dystrophy

A

expansion of cTG nucleotide in non coding region DPMK

135
Q

describe nieman pick disease

A

neurodegenerative disease with defect in intracellular cholesterol trafficking

136
Q

presentation of nieman pick disease

A

cherry red spot
vertical supranuclear gaze plasy
severe jaundice
hepatosplenomegaly
present before age of 10

137
Q

describe features of non ketotic hyperglycinaemia

A

neonatal encephalopathy
‘hiccups’
poor feeding
apnoeas
myoclonic fits
non dysmorphic
hypotonia

normal acid base and ammonia levels
high levels of glycine

138
Q

describe mucopolysaccharidosis type 1

A

lyososomal storage disorder by mutations in IUDA gene

failure to breakdown glycosaminoglycans (GAGs) leads to accumulation and multi organ disease

hurler syndrome = subtype

139
Q

presentation of mucopolycaccharidosis type 1

A

normal development and then plateua and regression
reduced growth
mixing hearing impairments
recurrent upper resp tract infections
micrognathia, macroglossia
hepatosplenomegaly
corneal clouding/ opacity
short stubby fingers

140
Q

test for mucopolysaccharidosis type 1

A

elevated urine glycosaminoglycans (GAGs)

141
Q

enzyme increased in gauchers disease

A

acid phosphatase increased

142
Q

presentation of refsums disease

A

chronic ataxia and peripheral neuropathy
deafness
retinitis pigmentosa
anosmia
itchy skin

143
Q

cause of refsums disease

A

lack enzyme in peroxisosomes so phytatic acid accumulates

144
Q

describe glycogen storage disorders

A

lack the enzyme for glycogen metabolism to glucose
causes hypoglycaemia and lactic acidosis

slowly progressive clinical picture with dysmorphic features + organomegaly + skeletal dysplasia + developmental degression

145
Q

describe mcardles disease (type V glycogen storage disorder)

A

deficiency of enzyme phosphylase in the muscle so there is blocked breakdown of glycogen in the muscle

146
Q

presentation of mcardles disease (type V glycogen storage disorder)

A

pain and weakness in the muscles when exercising -> relieved when exercise stopped
myopathy

147
Q

investigations for mcardles disease

A
  1. lactic acidosis
  2. urine myoglobunuria (rhabdomyolysis)
148
Q

describe pompes disease

A

mutation in lysosomal transport system that degrades glycogen into glucose
autosomal recessive

149
Q

presentation of pompes disease (glycogen storage disorder type 2)

A

cardiomyopathy + heart failure
faltering growth
hypotonia
hypoglycaemia
hearing loss
large tongue

150
Q

describe arginase deficiency (urea cycle disorder)

A

autosomal recessive
mutation in AR1 gene
elevated alanine, glutamine and arginine
present at 1-3 y/o with poor growth, developmental regression, seizures, spasticity

151
Q

describe cause of ornithine transcarbamylase (urea cycle disorder)

A

X linked recessive
mutation in OTC gene

152
Q

test results for ornithine transcarbamylase

A

high urine ototic acid
high alanine and high glutamine levels
low citrulline and low arginine

153
Q

describe citrullinaemia

A

autosomal recessive
mutation in ASS7 gene
deficiency arginosuccinate synthetase so stops synthesis of arginosuccinate in cytoplasm

154
Q

presentation of urea cycle disorders

A

newborn presentation
vomiting
encephalopathy from high ammonia levels
seizures
failure to feed

155
Q

tests for urea cycle disorders

A

very high ammonia
resp alkalosis -> metabolic acidosis
urine for organic acids
normal glucose, normal ketones
high glutamine and alanine (nitrogen carrying amino acids)

156
Q

test for tyrosinaemia

A

urine succanylacetone positive

157
Q

presentation of tyrosinaemia

A

jaundice and liver damage
renal tubular injury
hypertrophic cardiomyopathy

158
Q

describe homocystinuria

A

disorder of conversion of methionine to cysteine causing accumulation of homocysteine

159
Q

presentation of homocystinuria

A

stiff joints
thrombosis
learning difficultues
sublexed lens -‘flashing lights’
weakness
long arm span

similar to marfans disease

160
Q

describe cause of glutaric aciduria type 1 and presentation

A

build up of lysine, tryptophan and hydrocylysine in basal ganglia

minor illness triggers dystonic movements and regression in development

161
Q

tests for maple syrup urine disease

A

high leucine levels
high ketones
normal blood gas

reduced neurological status

162
Q

tests for organic acid disorders

A

severe metabolic acidosis
large anion gap
hypoglycaemia or hyperglycaemia
raised ketones **
high ammonia

163
Q

describe NARP

A
  1. neuropathy
  2. ataxia
  3. retinitis pigmentosa

mitochondrial disorder - defect in ATP synthase

164
Q

describe features of pendred syndrome

A

b/l sensorineural deafness (most common form of inherited deafness)
dilated vestibular aqueducts
mild hypothyroidism

165
Q

what is VACTERL

A

V - vertebral e.g. hemivertebra
A- anorectal e.g. imperforate, anterior displaced
C- cardiac abnormalitie
T- tracheo oEsophageal atresia
R- Renal
L- limb problems

166
Q

presentation of myotonic dystrophy

A

antenatal polyhydramnios
hypotonia - decreased reflxes
clubbed foot
expressionless face (SMA has normal expression)
poor swallow
triangular mouth

167
Q

amino acids raised in viral gatstroenteritis

A

raised plasma leucine, valine and isoleucine

168
Q

presentation of lesch nyhan syndrome

A

elevated levels of uric acid

  • initial development delay and hypotonia
  • becomes spasticity and jerky and increased tone in movements
  • aggressive and self mutilation behaviour