Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Stage 2: Human Deveopment > Congenital Abnormalities > Flashcards

Congenital Abnormalities Flashcards

1
Q

What are the most common serious congenital disorders?

A

1) Heart defects
2) Neural tube defects (NTDs)
3) Down syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the types causes of congenital anomalies (although in many cases it is difficult to identify their cause)?

A

1) Genetic
2) Infectious
3) Environmental

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How can congenital rubella syndrome be prevented?

A

Timely vaccination of mothers during childhood and the reproductive years

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are key ways to prevent and treat many birth anomalies?

A

1) Adequate intake of folic acid
2) Iodine
3) Vaccination
4) Adequate antenatal care

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are birth defects/congenital disorders/malformations?

A

Structural or functional anomalies incl. metabolic disorders, which are present at the time of birth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What % of recognised pregnancies (more bc many people don’t know they are pregnant e.g. in first 2 weeks) are lost before 12 weeks gestation (first trimester) ?

A

15%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Why do spontaneously aborted pregnancies occur?

A
  • 80-85% have gross structural abnormalities

- 50% chromosomal abnormalities - trisomy, monosomy, triploidy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What does a malformation signify?

A

That fetal growth and development did not proceed normally due to underlying genetic, epigenetic or environmental factors that altered the development of a particular structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are causes of malformations?

A

1) Monogenic/Mendelian (7.5%) e.g. achondroplasia (AD), achondrogenesis (AR)
2) Chromosomal (6%) e.g. T21
3) Multifactorial (20%) e.g. NTDs, isolated congenital heart disease, cleft lip and palate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are genetic causes of malformations?

A

1) Ectrodactyly Ectoderm dysplasia clefting (EEC) - P63
2) Diastrophic dysplasia - SLC26A2
3) Apert syndrome - FGFR2 - complete syndactyly of digits of hands
4) Grieg syndrome - GLI3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are environmental causes of malformations?

A

1) Teratogens e.g. fetal valproate syndrome (similar symptoms to T21)
2) Thalidomide
3) Maternal medication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is diabetic embryopathy caused by?

A

Poorly controlled maternal diabetes (hyperglycaemia in utero - if mum didn’t have diabetes, could be genetic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the clinical features of diabetic embryopathy?

A

1) Midline facial defects
2) Microtia (underdevelopment of ears)
3) Microsomia
4) Large or small birth weight
5) CNS malformations
6) NTDs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are examples of congenital infections leading to specific syndromes/problems resulting from infection in pregnancy?

A

1) Zika
2) CMV
3) Rubella

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are clinical features of congenital zika syndrome?

A

1) Microcephaly
2) Problems with vision and hearing
3) Problems moving limbs and body
4) Damage to the brain (CNS defects)
5) Seizures
6) Problems with feeding (difficulty swallowing)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is a feature of congenital CMV?

A

Significant neurological disorders

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the 3 clinical features of congenital rubella syndrome?

A

1) Microcephaly
2) PDA (patent ductus arteriosus)
3) Cataracts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are syndromes?

A

Collections of consistent recognisable patterns of abnormalities, not necessarily genetic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are dysmorphisms?

A
  • Congenital malformations that have abnormal morphology
  • > 2400 described dysmorphic syndromes caused by single gene defect and chromosome imbalances
  • Syndrome may be associated with developmental delay
20
Q

What is the main cause of learning difficulties/intellectual disability/developmental delay?

A

Chromosomal abnormalities esp. Down’s syndrome (but many unknown causes)

21
Q

What is the baseline rate of major congenital abnormality?

A

1-2%
- Varies based on certain background facts e.g. poorly controlled diabetes, teratogenic drugs, previous baby with anomaly

22
Q

What abnormalities can be detected by US by organ?

A

1) Brain - acrania, holoprosencephaly
2) Spine - open spina bifida
3) Face - facial cleft, anopthalmia
4) Neck - cystic hygroma
5) Thorax - congenital diaphragmatic hernia
6) Abdominal wall - exomphalos, gastroschisis
7) Urinary tract - bilateral renal agenesis, urethral obstruction
8) Extremities - club foot, arthrogyposis
9) Skeleton - skeletal dysplasia, achondroplasia

23
Q

Why do you want to detect serious cardiac diseases on US?

A

So that the baby can be born at a specialist cardiac centre

24
Q

What congenital heart diseases can be seen on a four chambers view on an US?

A

1) Atrioventricular septal defect
2) Hypoplastic left heart syndrome
3) Ventricular septal defect
4) Ebstein’s anomaly

25
Q

What congenital heart diseases can be seen on a great vessels view on an US?

A

1) Transposition of the great arteries
2) Tetralogy of Fallot
3) Common arterial trunk
4) Coarctation of the aorta
5) Aortic valve stenosis

26
Q

Acrania - diagnostic features on US, prognosis, prevalence

A
  • US diagnosis = absence of ossified skull at 12 weeks or anencephaly at 16 weeks
  • Prognosis - lethal condition within first week of life (always riskier to stay pregnant than to terminate pregnancy)
  • Prevalence = 1:1000 at 12 weeks
27
Q

Alobar holoprosencephaly - diagnostic features on US, associated abnormalities, prognosis, prevalence

A
  • US diagnosis = forebrain abnormalities in transverse views
  • Associated abnormalities - T18 and T13 in > 50% of cases, genetic syndromes 20%
  • Prognosis - usually lethal in first year of life
  • Prevalence = 1:1300 at 12 weeks, 1:10,000 births
28
Q

Open spina bifida - diagnostic features on US, fetal therapy, prognosis, prevalence

A
  • US diagnosis = detailed examination of spine from head to sacrum, characteristic brain/skull findings = lemon or banana sign
  • Fetal therapy - closure by fetal surgery (open vs fetoscopy) may improve motor and urologic function
  • Prognosis - 35% 5 year mortality, 25% stillborn, surviving = paralysis, incontinence, normal intelligence
  • Prevalence = 1:1000 at 12 weeks
29
Q

Cleft lip and palate - diagnostic features on US, associated abnormalities, prognosis, prevalence

A
  • US diagnosis - detailed examination of face, can be picked up at 11-13 weeks, normally later
  • Associated abnormalities - 30% associated with variety of genetic syndromes
  • Prognosis - good if isolated, surgery at 3-6 months old, long term problems = dental, hearing, speech and psychological
  • Prevalence = 1:700, 50% (both lip and palate), 25% lip only, 25% palate only
30
Q

Diaphragmatic hernia - diagnostic features on US, associated abnormalities, fetal therapy, prognosis, prevalence

A
  • US diagnosis = defect in diaphragm, abdominal contents in thorax
  • Associated abnormalities = 20% chromosomal (T18/13), 10% genetic syndromes (e.g. Pallister-Killian Syndrome), 20% other systems defects
  • Fetal therapy - fetoscopic placement of balloon in trachea at 26 weeks (current RCT)
  • Prognosis - good if isolated and mild, survival = <15% if severe, 50% if moderate, >90% if mild
  • Prevalence = 1:4000
31
Q

What should you do if you find one thing wrong on a fetal anomaly scan?

A

Keep looking to see if there are more, bc mild deformities may be ok but might also indicate other symptoms

32
Q

What two NTDs count for 90% of all NTDs?

A

Anencephaly and spina bifida

33
Q

Describe the types of anencephaly and spina bifida cases

A
  • All anencephaly and most spina bifida cases are open defects where the neural tissue and meninges are exposed
  • 15-20% are closed where skin covers the defect and these are not detectable by biochemical testing
34
Q

What should be taken to prevent NTDs?

A

Folic acid - 2 months prior to pregnancy and 2 months into the pregnancy

35
Q

Describe the features of autosomal dominant inheritance

A
  • 50% recurrence risk
  • High new mutation rate
  • Variable gene expression and penetrance due to e.g. modifier genes, response to DNA damage, carcinogens and hormonal/reproductive factors
  • Even in one family, different people with the same mutation will have different phenotypes depending on the penetrance
36
Q

Describe the features of autosomal recessive inheritance

A
  • Often rare conditions
  • Usually in one generation
  • Increased risk with consanguinity
  • Parents usually obligate carriers
  • 25% recurrence risk at conception
  • ⅔ chance that unaffected sibling is a carrier
  • e.g. oculocutaneous albinism, MPS (Mucopolysaccharidosis), BBS (Bardet-Biedl syndrome)
37
Q

Describe the features of X-linked recessive inheritance

A
  • 1 in 4 risk at conception
  • 1 in 2 risk for male
  • Males more severely affected
  • Possible lethality in affected male
  • Manifesting carrier female
  • e.g. Duchenne muscular dystrophy (DMD)
38
Q

How would you assess someone with a congenital abnormality?

A

1) FH - 3 generation family tree esp. for X-linked disorder incl. age of adult onset disorders
2) Pregnancy history - maternal illness e.g. diabetes, medicines incl. drugs and alcohol, scan data, birth history
3) Developmental history - e.g. motor or speech delay
4) PMH - e.g. repaired congenital heart disease, anal atresia
5) Examination - growth parameters, objective description of congenital malformations, dysmorphology assessment
6) Investigations - array CGH, mutation testing for suspected single gene

39
Q

What are the clinical features of DMD?

A
  • Onset at 3-6 years
  • Progressive weakness
  • Pseudohypertrophy of calf muscles
  • Spinal deformity
  • Cardiopulmonary involvement
  • Mild to moderate MR
  • Significant weakness, disability and deformity leads to a lower life expectancy
  • Muscle weakness in all muscles leading to signs all around the body e.g. belly sticking out due to weak belly muscles and knees may and to take weight
40
Q

What are the features of myotonic dystrophy?

A
  • Autosomal dominant
  • Distal myopathy
  • Prolonged muscle contraction e.g. problems with opening lids or relaxing hands after squeezing hands
  • Heart conduction defect
  • Diabetes
  • Early onset cataract
  • 40 repeats is normal, the more repeats you have the more severe and earlier onset the disease becomes (mild to adult to childhood to congenital)
  • Triplet repeat disorder
  • Expansion becomes worse when passed to offspring (parent may only have v mild symptoms)
41
Q

What are the features of congenital myotonic dystrophy?

A
  • Genomic anticipation
  • Most severe form
  • Congenital hypotonia
  • Joint contractures (talipes)
  • Respiratory failure
  • Facial weakness
  • Swallowing difficulties
  • Developmental delay
  • Autism spectrum disorder
  • Massive expansion of myotonic dystrophy gene leads to severely hypotonic baby
  • At 16-18 week scan may see reduced mobility, contracture of knee, right hand clenched
  • Poor life expectancy, may terminate pregnancy
42
Q

What are the clinical features of Noonan syndrome?

A
  • Facial dysmorphology - up slanting eyes, wider neck
  • Pulmonary stenosis
  • Short stature
  • Intellectual disability
43
Q

What are examples of mutations in genes which function in the same pathway that may cause similar but distinct clinical phenotypes (Noonan syndrome)?

A

Some phenotypic overlap with (genes interact with one another):

  • Neurofibromatosis type 1 - especially NF1 and valvular pulmonary stenosis (similar Noonan-like faces - AKA Watson syndrome)
  • Cardio-facial-cutaneous syndrome - more severe learning difficulties and sparse hair/lack of eyebrows
  • Costello syndrome - severe developmental delay and learning difficulties and increased risk of malignancy
44
Q

What are the clinical features of neurofibromatosis type 1 (variable expression)?

A
  • Autosomal dominant
  • Caused by mutations (deletion) in the NF1 gene
  • Causes lumps/neurofibromas or v complex lumps on internal peripheral nerves called plexiforms
  • Freckling of eyes (Lisch nodules)
  • Coffee coloured patches (cafe au lait spots)
  • Bony defects incl. scoliosis and tibial bowing
  • Predisposition to developing tumours esp. optic gliomas on the optic nerve
45
Q

What are the two types of monogenic disorders?

A

1) Inherited/familial

2) De novo

46
Q

What are examples of monogenic disorders?

A

1) Spinal muscular atrophy (SMA)
2) Cystic fibrosis (CF)
3) Duchenne muscular dystrophy (DMD)

47
Q

When would a prenatal referral be done for a monogenic disorder?

A

1) Due to FH of disorder

2) Due to US indicators e.g. echogenic bowel may indicate CF

Stage 2: Human Deveopment (34 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions