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Year 4- Paediatrics > Genetic Conditions > Flashcards

Genetic Conditions Flashcards

1
Q

What is the different between phenotype and genotype?

A 
Genotype= the genes that we have 
Phenotype= the physical expression of the genes that we have
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2
Q

What is mendelian inheritance?

A

This type of inheritance occurs when there is a disease caused by a single abnormal gene on one of the non sex chromosomes

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3
Q

What is a chromosome disorder?

A

Conditions where there is either a structural abnormality, an extra abnormal portion or an abnormal number of chromosomes compared to normal.

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4
Q

What is an example of a chromosome deletion disorder?

A

Cri du chat which presents with a cat like cry

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5
Q

What is a chromosomal duplication disorder?

A

This occurs where a portion of chromosome is duplicated

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6
Q

What is an example of a chromosomal duplication disorder?

A

Charcot Marie tooth

Sensory and motor neuropathy soth characteristic high arched feet

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7
Q

What is a translocation disorder?

A

Occurs where a portion of one chromosome is directly swapped with another chromosome.
The swap can be balanced (reciprocal translocations)
Unbalanced (nonreciprocal translocations) this is where a portion of the chromosome leaves the first chromosome and attaches to another without an exchange taking place.

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8
Q

What does translocation usually cause?

A

Translocation does not usually lead to a specific genetic syndrome but often predisposes to other conditions such as cancer and infertility

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9
Q

When does the philadelphia chromosome translocation occur?

A

This is a reciprocal translocation between chromosome 9 and 22 and it occurs in acute myeloid leukaemia.

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10
Q

Trisomy is when the person has an extra chromosome, what are the 3 trisomys which you should know about?

A

Patau syndrome
This is a trisomy 13

Edwards syndrome
This is a trisomy 18

Downs
This is trisomy 21

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11
Q

What is mosaicism?

A

This is where the chromosomal abnormality actually happens after conception. The abnormality occurs in portions of the cells in the body and not in others and is unpredictable.

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12
Q

What is predictive testing?

A

Involves testing a person for a specific gene mutation that has implications for them in the future
Ie: BRCA1 gene or the gene for huntingtons

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13
Q

What is karyotyping?

A

Involves looking at the number of chromosomes, their size and their basic structure

It is useful in diagnosing DOWN syndrome (trisomy 21) and turner syndrome (45XO)

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14
Q

What are the features of downs syndrome?

A 
Hypotonia
Brachycephaly (small head with flat back) 
Single palmar crease 
Short neck 
Short stature 
Flattened face and nose 
Prominent epicanthic folds 
Upwards slopping palpebral fissure
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15
Q

What are the complications of downs syndrome?

A

1 in 3 have heart problems- particularly ASD, VSD, PDA, teratology of fallot

Recurrent otitis media

Deafness

Eye problems- myopia, strabismus, cataracts

Hypothyroidism

Atlantoaxial instability

Leukaemia is more common in children with Downs

Dementia

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16
Q

What is the combined test for downs syndrome?

A

This involves blood results combined with ultrasound results

Bloods: PAPPA and Beta HCG

Ultrasound: measuring the nuchal translucency (thickness of the back of the neck of the fetus)

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17
Q

What is the triple test for downs syndrome?

A

Beta HCG
Serum oestriol
AFP

18
Q

What is the quadruple test for DOWNs syndrome?

A

Inhibin A
Beta HCG
PAPPA
AFP

19
Q

The screening tests for down syndrome show the risk of the mother having down syndrome, over what risk level is the woman offered amniocentesis/ chorionic villus sampling?

A

When the risk is greater than 1 in 150 (5%)
These tests involve taking a sample of the fetal cells which then undergo karyotyping to give a definitive answer to whether the fetus is affected by Downs or not.

20
Q

When would you use chorionic villus sampling and when would you use amniocentesis?

A

. Chorionic villus sampling is used when testing is done in earlier pregnancy (<15 weeks)
. Amniocentesis is done later in pregnancy when there is enough amniotic fluid to make it safer to take a sample

21
Q

What is the risk of miscarriage for amniocentesis/chorionic villus sampling?

A

The chance of miscarriage after CVS is 1 in 100

Amniocentesis carried out between the 15th and 20th week and again the same miscarriage chance

22
Q

What is a new method thats being used instead of chorionic villus sampling/amniocentesis?

A

Non invasive prenatal testing

23
Q

What is the management of down syndrome?

A 
Management will involve members of a MDT 
Occupational therapy 
Speech and language therapy 
Physiotherapy 
Dietitian 
Some routine follow ups are important for children with downs syndrome?
Eye checks 
Hearing checks (audiometry) 
Regular thyroid checks (2 yearly) 
Echocardiogram to detect cardiac defects
Etc etc
24
Q

What is kleinfelter syndrome?

A

This is when a male has an additional X chromosome.

Rarely males can have more than one additional X chromosome

25
Q

What are the features of klinefelter syndrome?

A

Usually patients will appear as normal males until puberty
At puberty they may develop features suggestive of their condition…

. Taller height 
. Wider hips 
. Gynaecomastia 
. Weaker muscles 
. Small testicles 
. Reduced libido 
. Shyness 
. Infertility 
. Subtle learning difficulties
26
Q

What are the management options of Klinefelter syndrome?

A

Testosterone injections
Advanced IVF techniques have the ability to allow fertility
Breast reduction surgery for cosmetic purposes

MDT input: speech and language, occupational therapy, physiotherapy, educational support for dyslexia and other learning difficulties.

27
Q

What are the complications of klinefelter syndrome?

A

Breast cancer (compared with other males but still less than females)
Osteoporosis
Diabetes
Anxiety and depression

28
Q

What is turners syndrome?

A

This is where a female has a single X chromosome making them 45XO (the O refers to an empty space where the other chromosome should be).

29
Q

Cubital valgus is a feature of turners syndrome, What is cubitus valgus?

A

An abnormal features of the elbow, when the arm is extended downwards with the palms facing forward. The angle of the forearm at the elbow is exaggerated angled away from the body.

30
Q

What are the features of turners syndrome?

A 
Short stature 
Webbed neck 
High arching palate 
Downward sloping eyes with ptosis 
Broad chest with widely spaced nipples 
Cubitus valgus 
Underdeveloped ovaries with reduced function 
Late or incomplete puberty 
Most females are infertile
31
Q

What are the associated conditions of turners?

A 
Recurrent otitis media 
Recurrent UTI 
Coarctation of the aorta 
Hypothyroidism 
Hypertension 
Obesity 
Diabetes 
Osteoporosis 
Various specific learning disabilities
32
Q

What are the management options for turners syndrome?

A

. Growth hormone therapy can be used to prevent short stature
. Oestrogen and progesterone replacement to help establish female secondary sex characteristics, regulate menstrual cycle and prevent osteoporosis
. Fertility treatment can increase chances of becoming pregnant

Associated conditions like hypothyroidism and hypertension should be treated appropriately.

33
Q

What is noonan syndrome?

A

Genetic condition
Autosomal dominant

Thought to be the male ‘turners’

34
Q

As well as features similar to turners, what other features would someone with noonan syndrome have?

A 
Pulmonary valve stenosis 
Ptosis
Triangular shaped face 
Low set ears 
Coagulation problems: factor XI deficiency
35
Q

What is marfan syndrome?

A

Autosomal dominant conditions which affects the gene coding for fibrillin
Fibrillin is an important component of connective tissue, which means that people with Marfans have features resulting from abnormal connective tissue

36
Q

What are the features of marfan syndrome?

A 
Tall stature 
Long neck 
Long limbs
Long fingers (arachnodactyly) 
High arch palate 
Hypermobility 
Pectus carniatum/pectus excavatum 
Downward slopping palpable fissures
37
Q

What would someone with Marfan syndrome present like in an OSCE?

A

Tall
Hypermobility
A murmur suggestive of mitral or aortic regurgitation

38
Q

What are the associated conditions of marfan syndrome?

A 
Lens dislocation in the eye 
Joint dislocations and pain due to hypermobility 
Scoliosis of the spine 
Pneumothorax 
GORD 
Mitral valve prolapse (with regurgitation) 
Aortic valve prolapse (with regurg) 
Aortic aneurysms
39
Q

What is the management of marfans syndrome?

A

The main risks are the cardiac complications, particularly valve prolapse and aortic aneurysms
Where these complications occur they may require surgical correction

Also you can minimise the cardiovascular risk to minimise blood pressure and heart rate to reduce stress on heart and other complications occuring

Physiotherapy

Yearly opthalmologist and echocardiograms

40
Q

What is fragile X syndrome?

A

This is caused by a mutation in the FMR1 (fragile X mental retardation 1) gene on the X chromosome. The FMR1 gene codes for fragile X mental retardation protein which plays a role in cognitive development of the brain.

41
Q

What are the clinical features of fragile X syndrome?

A 
Delay in speech and language development 
Intellectual disability 
Long, narrow face 
Large ears 
Large testicles after puberty
Hypermobile joints
ADHD
Autism 
Seizures
42
Q

What is the treatment of fragile X syndrome?

A

No cure for the condition
Supportive and involves treating the symptoms
Involves MDT

Year 4- Paediatrics (21 decks)

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