Chromosomal Abnormalities Flashcards

1
Q

What is the mutation in Patau’s?

A

Trisomy 13

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2
Q

What is the clinical presentation of Patau’s?

A
  • Microcephaly
  • Micropthalmia
  • Cleft Palate/ lip
  • Polydactyly
  • Omphalocele/ gastroschisis
  • Cardiac defects (VSD, PDA, dextrocardia)
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3
Q

What is the mutation in Edward’s?

A

Trisomy 18

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4
Q

What is the presentation of Edward’s?

A
  • Rocker bottom feet
  • Overlapping fingers
  • Intellectual disability
  • Low-set ears
  • Low birth weight
  • Omphalocele/ gastroschisis
  • Cardiac/ renal and GI abnormalities
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5
Q

What is the difference between an omphalocele and gastroschisis?

A

Omphalocele is covered with a membrane, gastroschisis is not

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6
Q

What is the mutation in Down’s syndrome?

A

Trisomy 21

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7
Q

What is the mutation in Noonan’s syndrome?

A

Mutated RAS/ Mitogen activated protein kinase

PTPN11 gene associated with pulmonary stenosis

RAF1 gene associated with cardiomyopathy

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8
Q

What is the presentation of Noonan’s?

A
  • Webbed neck
  • Trident hairline
  • Cardiac (cardiomyopathy, pulmonary stenosis)
  • Pectus excavatum
  • Short stature
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9
Q

What is the mutation in Prader-Willi Syndrome?

A

Deletion PWS section of q arm chromosome 15

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10
Q

What is the difference between Prader Willi and Angelman’s syndrome?

A

Prader Willi is a lack of the paternal PWS region on chromosome 15

Angelman is a lack of maternal PWS region on chromosome 15

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11
Q

What is the presentation of Angelman syndrome?

A
  • Cognitive impairment
  • Ataxia
  • Epilepsy (myoclonic seizures)
  • Abnormal facial appearance
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12
Q

What is the presentation of PWS?

A

Fat, floppy, flacid
- Hypotonia
- Hyperphagia
- Almond-shaped eyes
- Obesity (in later childhood due to insatiable appetite)
- Hypogonadism
- Epicanthal folds
- Flat nasal bridge and upturned nose
- Intellectual disability

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13
Q

What is the mutation in Turner’s syndrome?

A

45X

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14
Q

What is the presentation of Turner’s syndrome?

A
  • Short stature
  • Primary amenorrhoea
  • Delayed puberty (lack of 2ndary sexual characteristics)
  • Widely spaced nipples
  • Intellectual disability
  • Webbed neck
  • Infertility
  • Hypothyroidism
  • Omphalocele/ gastroschisis
  • Bicuspid aortic valve > aortic coarctation (ESM over aortic valve)
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15
Q

What is the mutation in Klienfelter’s?

A

47XXY

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16
Q

What is the presentation of Klienfelter’s?

A
  • Infertility
  • Hypogonadism (microorchidism)
  • Gynaecomastia
  • Tall stature
17
Q

What is the presentation of fragile X syndrome?

A
  • IQ 20-80 (2nd most common cause of low IQ after down’s)
  • Macrocephaly
  • Macroorchidism
  • Large, low set ears
  • Long, thin face
  • Autism
  • Joint laxity
  • Scoliosis
  • Mitral valve prolapse
17
Q

What is the mutation in fragile X syndrome?

A

CGG trinucleotide repeat expansion mutation (fragile)

FMR1 gene

18
Q

What is the presentation of foetal alcohol syndrome?

A
  • Microcephaly
  • Absent philtrum
  • Cardiac abnormalities
  • Reduced IQ
  • IUGR
  • Small upper lip
19
Q

What is the presentation of varicella in utero?

A
  • Skin scarring
  • Eye defects (micropthalmia)
  • Neurological defects (low IQ, microcephaly)
20
Q

What is the presentation of syphilis contracted in utero?

A
  • Rhinitis
  • Saddle-nose
  • Sensorineural deafness
  • Hepatosplenomegaly
  • Jaundice
21
Q

What is the inheritance pattern of Noonan’s?

A

Autosomal dominant

22
Q

What is the management of PWS/ Angelman’s?

A
  • Growth hormone if evidence of growth failure
  • Management of feeding and obesity
23
Q

What is the managment of Turner’s syndrome?

A
  • Growth hormone therapy (plot heigh on syndrome specific growth charts)
  • Oestrogen replacement (at time of puberty for development of secondary sexual characteristics)
24
How many TNT repeats are required for fragile X syndrome to develop?
>200 Mutation is unstable and can expand between subsequent generations resulting in more severe forms of the disease
25
What is the most common chromosomal pathology causing Down's syndrome?
Meiotic non-dysjunction (maternal age) 95% - error at meiosis, pair of chromosome 21 fails to separate
26
What is the 2nd most common chromosomal pathology causing down's syndrome?
Translocation (5%) Robertsonian translocation - extra chromosome 21 joined to another chromosome (usually 14) Paternal chromosome analysis recommended - risk of recurrence 10-15% if mother is a translocation carrier
27
What is the 3rd most common translocation causing down's syndrome?
Mosaicism (1%) Milder phenotype, some cells normal some have trisomy 21
28
What is the immediate management of trisomy 21?
- ECG (AVSD) and evaluation by paediatricians (duodenal atresia) - Genetic counselling Early intervention programmes to reduce developmental delay: - Physiotherapy - prevent abnormal compensatory movements for physical limitations - Occupational therapy - fine motor and self-care - SALT - speech intelligibility and manage language delay
29
What is the long-term management of trisomy 21?
- Annual hearing test, thyroid levels and ophthalmic evaluation (up to 5 years then every 2 years) - Haemoglobin levels for IDA - Monitor symptoms for OSA - Monitor growth using updated Down's syndrom growth charts
30
Which two syndromes (congenital) are associated with Wilm's tumour development?
WAGR syndrome Beckwith Weidermann syndrome
31
What is the presentation of WAGR syndrome?
W - Wilm's tumour A - Anaridia G - GU malformations R - Range of developmental delays
32
What is the presentation of Beckwith Weidermann syndrome?
- Large body habitus at birth - Macroglossia - Tall for age
33