Genetics

Question 1

Causes of Down syndrome

Answer 1

• nondisjunction
• translocation
• mosaicism

Question 2

Mean IQ in Down syndrome

Answer 2

45-48

Question 3

Down syndrome facies

Answer 3

• Brachcephaly
• upslanted palpebral fissures
• Brushfield spots
• epicanthic folds
• flat nasal bridge
• low set ears
• protruding tongue

Question 4

Risks associated with Down syndrome

Answer 4

• congenital heart disease
• ophthalmologic disorders
• hearing loss
• thyroid dysfunction
• stuctural GIT problems (dudenal atresia, Hirschsprung’s)
• Coeliac disease
• myelodysplasia
• leukaemia
• dementia
• obesity

Question 5

Phenotypic features of Edward syndrome (T18)

Answer 5

• micrognathia
• low set ears
• rockerbottom feet
• club feet
• congenital heart disease
• diaphragmatic hernia/ omphalocoele
• overlapping fingers
• neural tube defects

Question 6

Phenotypic features of Patau syndrome (T13)

Answer 6

• holprosencephaly
• hypotelorism
• micro/anopthalmia
• cutis aplasia
• low set ears
• overrinding fingers
• congenital heart disease
• enlarged kidneys
• cleft lip and palate

Question 7

Phenotypic features of Turner syndrome

Answer 7

45X

• hydrops fetalis
• puffy feet
• webbed neck
• short stature
• ovarian dysgenesis
• coarctation of aorta
• ASD/VSD/ bicuspid aortic valve

Question 8

Phenotypic features of Klinefelter syndrome

Answer 8

47XXY

• tall stature
• hypogonadism
• gynaecomastia
• mild ID

Question 9

Features of 22q deletion syndrome (Di George)

Answer 9

• cleft palate
• thymic hypoplasia
• CHD
• midface hypoplasia
• decreased upper helices of ears
• learning difficulties
• tapered fingers
• increase in psychiatric disease

Question 10

Features of Williams syndrome

Answer 10

• developmental delay
• short stature
• periorbital fullness
• big ears
• outgoing persoality/ musicality
• AS/PS
• infantile hypercalcaemia

Question 11

Features of Prader Willi syndrome

Answer 11

• low birth weight/poor feeding
• insatiable appetite and obesity
• rosebud mouth
• almond shaped palpebral fissures
• small hands and feet
• diabetes, hypertension, psychiatric problems

Question 12

Features of Angelman syndrome

Answer 12

• increased tone
• jerky movements
• microcephaly
• seizures
• beaked nose, wide mouth

Question 13

Example of autosomal recessive disorders

Answer 13

• cystic fibrosis
• sickle cell disease
• albinism
• spinal muscular atrophy
• Bardet Biedl syndrome
• metabolic disorders

Question 14

Features of neurofibromatosis type 1

Answer 14

• Cafe au lait spots >5
• inguinal and axillary freckling
• Lisch nodules
• Plexiform neurofibroma
• specific bone abnormalities (tibial pseudoarthrosis)
• increased tumor risk
• LD/ ADHD

Question 15

X-linked disorders

Answer 15

• Duschenne muscular dystrophy
• Haemophilia A/B
• Fragile X syndrome