GENETIC DISORDERS AND CONGENITAL SYNDROMES Flashcards Preview

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Flashcards in GENETIC DISORDERS AND CONGENITAL SYNDROMES Deck (51):
1

What term best describes the inheritance pattern of Marfan's syndrome?

Autosomal dominant

2

What term best describes the inheritance pattern of sickle cell disease?

Autosomal recessive

3

What term best describes the inheritance pattern of thalassaemia?

Autosomal recessive

4

What term best describes the inheritance pattern of Haemophilia A and B?

X-linked recessive

5

What term best describes the inheritance pattern of neurofibromatosis type 1?

Autosomal dominant

6

What term best describes the inheritance pattern of colour blindness?

X-linked recessive

7

What term best describes the inheritance pattern of Duchenne muscular dystrophy?

X-linked recessive

8

What term best describes the inheritance pattern of myotonic dystrophy?

Autosomal dominant

9

What term best describes the inheritance pattern of phenylketonuria?

Autosomal recessive

10

What term best describes the inheritance pattern of congenital adrenal hyperplasia?

Autosomal recessive

11

What term best describes the inheritance pattern of tuberous sclerosis?

Autosomal dominant

12

What term best describes the inheritance pattern of Fragile X syndrome?

X-linked recessive

13

What term best describes the inheritance pattern of cystic fibrosis?

Autosomal recessive

14

What term best describes the inheritance pattern of G6PD?

X-linked recessive

15

What term best describes the inheritance pattern of achondroplasia?

Autosomal dominant

16

What is the most common genetic cause of severe learning difficulties?

Fragile X syndrome

17

What is the mutation in Fragile X syndrome?

Expansion of a triplet repeat in the FRAXA gene

18

What are the clinical features of Fragile X syndrome?

Learning difficulties

Macrocephaly

Long face

Large ears

Macro-orchidism (large testes)

Taller than average

19

What is the other name for trisomy 13?

Patau syndrome

20

What are the features of Patau syndrome (trisomy 13)?

Microcephalic, small eyes

Cleft lip/palate

Polydactyly

Scalp lesions

21

What is the other name for trisomy 18?

Edwards syndrome

22

What are the features of Edwards syndrome (trisomy 18)?

Micrognathia - undersized jaw

Low-set ears

Rocker bottom feet

Overlapping of fingers

23

What is the other name for trisomy 21?

Down syndrome

24

What are the dysmorphic facial features of Down syndrome?

Round face

Epicanthic folds

Flat nasal bridge

Protruding tongue

Small ears

Brushfield spots on iris

25

What are the non-facial dysmorphic features of Down syndrome?

Single palmar crease

Flat occiput

Incurved little fingers

Gap between first and second toes

Small stature

26

What are the structural defects associated with Down syndrome?

Cardiac defects (VSDs)

Duodenal atresia (remember double bubble sign on x-ray)

27

What are the neurological features of Down syndrome?

Hypotonia

Developmental delay

Mean IQ of 50

28

What are the late medical complications of Down syndrome?

Increased risk of leukaemia

Respiratory infections

Hypothyroidism

Alzheimer's disease

Atlantoaxial instability

Coeliac disease

29

What is the chromosomal defect that causes Turner syndrome?

45 XO - only 1 X chromosome

30

Is maternal age related to Turner syndrome, Down syndrome and Patau syndrome?

No. Age is not related to Turner syndrome. It is a risk factor for the other two.

31

What are the dysmorphic features of Turner syndrome?

Lymphoedema of the hands and feet at birth

Neck webbing

Widely spaced nipples

Wide carrying angle (cubitus valgus)

Short stature

32

What are the structural and functional abnormalities associated with Turner syndrome?

Gonadal dysgenesis - streak ovaries

Congenital heart disease, particularly coarctation of the aorta

Renal abnormalities

Specific learning difficulties - visuo-spatial

33

What therapies can be offered to people with Turner syndrome?

Growth hormone improves final height

Oestrogen therapy is given at 11 to produce maturation of secondary sexual characteristics including breast development

Towards the end of puberty, progestogen is added to maintain uterine health and allow monthly withdrawal bleeds

IVF will usually be needed to achieve pregnancy although natural pregnancy can occur

34

What is the chromosomal abnormality that causes Klinefelter syndrome?

47 XXY

35

What are the clinical features of Klinefelter syndrome?

Tall stature with long legs

Small testes

Gynaecomastia

Learning difficulties

36

What treatment might be needed for someone with Klinefelter syndrome?

Testosterone to stimulate development of secondary sexual characteristics

37

What are the features of Noonan syndrome?

Referred to as the male version of Turner syndrome:

Webbed neck

Pectus excavatum

Short stature

Pulmonary stenosis

38

What are the features of Pierre-Robin syndrome?

Very similar to Treacher Collins syndrome:

Micrognathia

Posterior displacement of the tongue (may result in upper airway obstruction)

Cleft palate

39

What are the features of Prader Willi syndrome?

Hypotonia

Hypogonadism

Obesity

Inherited through imprinting (does not inherit gene from father)

40

What are the features of William's syndrome?

Short stature

Learning difficulties

Friendly, extrovert personality

Transient neonatal hypercalcaemia

Supravalvular aortic stenosis

41

What are the features of fetal alcohol syndrome?

Saddle-shaped nose

Maxillary hypoplasia

Absent philtrum between the nose and upper lip

Short, thin upper lip

Development delay

Cardiac defects - particularly ASD

42

What are the features of baby born to opiate users?

Evidence of drug withdrawal:

Jitterness

Sneezing

Yawning

Poor feeding

Vomiting

Diarrhoea

Weight loss

Seizures

43

A 14-year-old boy is brought in by his mother who noticed her child had repeated episodes of slurred speech and gait abnormalities. On musculoskeletal examination, you notice muscle weakness, dysdiadochokinesis and spinal scoliosis. What is the mode of inheritance of this condition?

X-linked recessive

Autosomal dominant

Point mutation

X-linked dominant

Autosomal recessive

Autosomal recessive - This is Friedrich's ataxia

44

What are the features of Friedrich's ataxia?

Bilateral spastic paresis

Bilateral loss of proprioception (dysdiadochokinesis) and vibration sensation

Bilateral limb ataxia

Scoliosis

45

What are the spinal tracts affected by Friedrich's ataxia?

Lateral corticospinal tracts

Dorsal columns

Spinocerebellar tracts

46

Autosomal recessive conditions are often thought to be 'metabolic' as opposed to autosomal dominant conditions being 'structural'. What are the metabolic conditions that do not follow this rule?

Hunter's and G6PD are X-linked recessive

Hyperlipidemia type II and hypokalemic periodic paralysis are autosomal dominant

47

Autosomal recessive conditions are often thought to be 'metabolic' as opposed to autosomal dominant conditions being 'structural'. What are the structural conditions that do not follow this rule?

Ataxia telangiectasia and Friedreich's ataxia are autosomal recessive

48

A 14-year-old male being investigated for iron-deficiency anaemia is found to have numerous polyps in his jejunum. On examination he is also noted to have pigmented lesions on his palms and soles. What is the likely diagnosis?

Hereditary non-polyposis colorectal carcinoma

Gardner's syndrome

Familial adenomatous polyposis

Peutz-Jeghers syndrome

Hereditary haemorrhagic telangiectasia

Peutz-Jeghers syndrome

49

What are the clinical features of Peutz-Jeghers syndrome?

Hamartomatous polyps in GI tract (mainly small bowel)

Pigmented lesions on lips, oral mucosa, face, palms and soles

Intestinal obstruction e.g. intussusception

Gastrointestinal bleeding

50

What is the inheritance pattern of Peutz-Jeghers syndrome?

Autosomal dominant

51

What is the prognosis of someone with Peutz-Jeghers syndrome?

Around 50% of patients will have died from a gastrointestinal tract cancer by the age of 60 years.