Genetics

Question 1

Marfan’s Syndrome

Answer 1

Marfan’s syndrome occurs due to a mutation in the fibrillin gene.

Question 2

HHT

Answer 2

HHT carries an autosomal dominant inheritance pattern.

Question 3

Autosomal Dominant

Answer 3

• Both homozygotes and heterozygotes manifest disease (there is no carrier state)
• Both males and females affected
• Only affected individuals can pass on disease
• Disease is passed on to 50% of children
• Normally appears in every generation.
• The risk remains same for each successive pregnancy

Question 4

Autosomal Dominant Conditions

Answer 4

Achondroplasia
Acute intermittent porphyria
Adult polycystic disease
Antithrombin III deficiency
Ehlers-Danlos syndrome
Familial adenomatous polyposis
Hereditary haemorrhagic telangiectasia
Hereditary spherocytosis
Hereditary non-polyposis colorectal carcinoma
Huntington’s disease
Hyperlipidaemia type II
Hypokalaemic periodic paralysis
Malignant hyperthermia
Marfan’s syndromes
Myotonic dystrophy
Neurofibromatosis
Noonan syndrome
Osteogenesis imperfecta
Peutz-Jeghers syndrome
Retinoblastoma
Romano-Ward syndrome
tuberous sclerosis
Von Hippel-Lindau syndrome
Von Willebrand’s disease

Question 5

Autosomal Recessive Conditions

Answer 5

Albinism
Ataxic telangiectasia
Congenital adrenal hyperplasia
Cystic fibrosis
Cystinuria
Familial Mediterranean Fever
Fanconi anaemia
Friedreich’s ataxia
Gilbert’s syndrome*
Glycogen storage disease
Haemochromatosis
Homocystinuria
Lipid storage disease: Tay-Sach’s, Gaucher, Niemann-Pick
Mucopolysaccharidoses: Hurler’s
PKU
Sickle cell anaemia
Thalassaemias
Wilson’s disease

Question 6

Patau syndrome ( Trisomy 13)

Answer 6

Microcephalic, small eyes
Cleft lip/palate
Polydactyly
Scalp lesions

Question 7

Edward’s syndrome ( Trisomy 18)

Answer 7

Micrognathia
Low-set ears
Rocker bottom feet
Overlapping of fingers

Question 8

Fragile X

Answer 8

Learning difficulties
Macrocephaly
Long face
Large ears
Macro-orchidism

Question 9

Noonan syndrome

Answer 9

Webbed neck
Pectus excavatum
Short stature
Pulmonary stenosis

Question 10

Pierre Robin syndrome

Answer 10

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

Question 11

Prader Willi syndrome

Answer 11

Hypotonia
Hypogonadism
Obesity

Question 12

William syndrome

Answer 12

Short stature
Learning difficulties
Friendly, extrovert personality
Transient neonatal hypercalcaemia
Supravalvular aortic stenosis

Question 13

Cri du chat syndrome (chromosome 5p deletion syndrome)

Answer 13

Characteristic cry (hence the name) due to larynx and neurological problems
Feeding difficulties and poor weight gain
Learning difficulties
Microcephaly and micrognathism
Hypertelorism