Flashcards in GENETIC DISORDERS AND CONGENITAL SYNDROMES Deck (51):
What term best describes the inheritance pattern of Marfan's syndrome?
What term best describes the inheritance pattern of sickle cell disease?
What term best describes the inheritance pattern of thalassaemia?
What term best describes the inheritance pattern of Haemophilia A and B?
What term best describes the inheritance pattern of neurofibromatosis type 1?
What term best describes the inheritance pattern of colour blindness?
What term best describes the inheritance pattern of Duchenne muscular dystrophy?
What term best describes the inheritance pattern of myotonic dystrophy?
What term best describes the inheritance pattern of phenylketonuria?
What term best describes the inheritance pattern of congenital adrenal hyperplasia?
What term best describes the inheritance pattern of tuberous sclerosis?
What term best describes the inheritance pattern of Fragile X syndrome?
What term best describes the inheritance pattern of cystic fibrosis?
What term best describes the inheritance pattern of G6PD?
What term best describes the inheritance pattern of achondroplasia?
What is the most common genetic cause of severe learning difficulties?
Fragile X syndrome
What is the mutation in Fragile X syndrome?
Expansion of a triplet repeat in the FRAXA gene
What are the clinical features of Fragile X syndrome?
Macro-orchidism (large testes)
Taller than average
What is the other name for trisomy 13?
What are the features of Patau syndrome (trisomy 13)?
Microcephalic, small eyes
What is the other name for trisomy 18?
What are the features of Edwards syndrome (trisomy 18)?
Micrognathia - undersized jaw
Rocker bottom feet
Overlapping of fingers
What is the other name for trisomy 21?
What are the dysmorphic facial features of Down syndrome?
Flat nasal bridge
Brushfield spots on iris
What are the non-facial dysmorphic features of Down syndrome?
Single palmar crease
Incurved little fingers
Gap between first and second toes
What are the structural defects associated with Down syndrome?
Cardiac defects (VSDs)
Duodenal atresia (remember double bubble sign on x-ray)
What are the neurological features of Down syndrome?
Mean IQ of 50
What are the late medical complications of Down syndrome?
Increased risk of leukaemia
What is the chromosomal defect that causes Turner syndrome?
45 XO - only 1 X chromosome
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.
What are the dysmorphic features of Turner syndrome?
Lymphoedema of the hands and feet at birth
Widely spaced nipples
Wide carrying angle (cubitus valgus)
What are the structural and functional abnormalities associated with Turner syndrome?
Gonadal dysgenesis - streak ovaries
Congenital heart disease, particularly coarctation of the aorta
Specific learning difficulties - visuo-spatial
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
What is the chromosomal abnormality that causes Klinefelter syndrome?
What are the clinical features of Klinefelter syndrome?
Tall stature with long legs
What treatment might be needed for someone with Klinefelter syndrome?
Testosterone to stimulate development of secondary sexual characteristics
What are the features of Noonan syndrome?
Referred to as the male version of Turner syndrome:
What are the features of Pierre-Robin syndrome?
Very similar to Treacher Collins syndrome:
Posterior displacement of the tongue (may result in upper airway obstruction)
What are the features of Prader Willi syndrome?
Inherited through imprinting (does not inherit gene from father)
What are the features of William's syndrome?
Friendly, extrovert personality
Transient neonatal hypercalcaemia
Supravalvular aortic stenosis
What are the features of fetal alcohol syndrome?
Absent philtrum between the nose and upper lip
Short, thin upper lip
Cardiac defects - particularly ASD
What are the features of baby born to opiate users?
Evidence of drug withdrawal:
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?
Autosomal recessive - This is Friedrich's ataxia
What are the features of Friedrich's ataxia?
Bilateral spastic paresis
Bilateral loss of proprioception (dysdiadochokinesis) and vibration sensation
Bilateral limb ataxia
What are the spinal tracts affected by Friedrich's ataxia?
Lateral corticospinal tracts
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
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
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
Familial adenomatous polyposis
Hereditary haemorrhagic telangiectasia
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
What is the inheritance pattern of Peutz-Jeghers syndrome?