Inheritance patterns

Question 1

Marfans

Answer 1

Autosomal dominant
Mutation Chr15 for fibrillin

Question 2

Hypertrophic cardiomyopathy

Answer 2

Autosomal dominant
Mutation in sarcomere protein

Question 3

Ehlers-Danlos

Answer 3

Mostly autosomal dominant except type 6 which is recessive

Question 4

Phenylketonuria

Answer 4

Autosomal recessive

Question 5

Adult polycystic kidney disease

Answer 5

Autosomal dominant

Question 6

Duchenne muscular dystrophy

Answer 6

X linked recessive

Question 7

Red-green colour blindness

Answer 7

X-linked recessive

Question 8

Achondroplasia

Answer 8

Autosomal dominant

Question 9

Tuberous sclerosis

Answer 9

Autosomal dominant

Question 10

Neurofibromatosis

Answer 10

Autosomal dominant

Question 11

Myotonic dystrophy

Answer 11

Autosomal dominant

Question 12

von Hippel-Lindau’s disease

Answer 12

Autosomal dominant

Question 13

Familial adenomatous polyposis coli

Answer 13

Autosomal dominant

Question 14

Familial hypercholesterolaemia

Answer 14

Autosomal dominant

Question 15

Alpha-1-antitrypsin deficiency

Answer 15

Autosomal recessive

Question 16

Congenital adrenal hyperplasia

Answer 16

Autosomal recessive

Question 17

Thalassaemia

Answer 17

Autosomal recessive

Question 18

Friedrich’s ataxia

Answer 18

Autosomal recessive

Question 19

Tay-Sach’s disease

Answer 19

Autosomal recessive

Question 20

Spinal muscular atrophy

Answer 20

Autosomal recessive

Question 21

Carrier rate for CF
General population
Common mutation screen negative

Answer 21

1:20
1:85

Question 22

Becker muscular dystrophy

Answer 22

X-linked recessive

Question 23

Haemophilia

Answer 23

X-linked recessive

Question 24

Whats is a chromosomal translocation?

Answer 24

Transfer of genetic material between two chromosomes - requires breakage and abnormal repair or accidental recombination between non-homologous chromosomes during meiosis

Question 25

What is a balanced translocation?

Answer 25

No genetic material lost, individiual normal
Carries risk of miscarrige/fetal anomaly

Question 26

What is a Robertsonian translocation

Answer 26

= centric fusion translocation
Breaks at / near centromere in two acrocentric chromosomes(centromere near one end of the chromosome) and fuses –> formation of single chromosome with two centromeres and acentric fragment (no centromere)
Healthy individual but potential for loss of genetic material at cell division

Question 27

What chromosomes most commonly involved in Robertsonian translocation?

Answer 27

1. Chr 13 and 14
2. Chr 14 and 21

Question 28

Familial downs syndrome
Rates

Answer 28

Translocation with Chr 21
Female carrier t(14;21) = 10% risk Downs
Male carrier t(14:21) = 1% risk Downs

Question 29

Mneumonic for X-linked Recessive

Answer 29

Little Alport Gave 6 Denmark Duchesses Fabrages Hunted from Home. Menke Couldn’t See, Only Pee, Which Always Surprised Isaac

Alports, G6PD, Duchennes MD, Fabreys, Hunters, Haemophilia, Menke, Red/Green colourblindness, nephrogenic DI, Wiskott Alrich Syndrome, X-linked ichthyosis

Question 30

Mneumonic for X-linked dominant

Answer 30

Fragile X Rates Ricketts

Rates = Retts syndrome

Question 31

Mnemonic for autosomal dominant

Answer 31

All Adult Elite Families Forbid Hunting Hippos, Men + Martians. Mileys New Neurones Ostentatiously Reimagined Spheres + Tubes with Willies +HIIT

Achrondoplasia, Adult PCKD, Ehlers-Danlos, Fam hypercholesterolaemia, FAP, Huntingtons, von Hipple Lindau, MEN, Marfans. Myotonic dystrophy, Noonans, neurofibromatosis, osteogenesis imperfecta, retinoblastoma, spherocytosis, TS, von Willebrand, HHT

Question 32

Gene involved in Angelman and Prader-Willi syndrome? Which parent?

Answer 32

Chromosome 15
Angelman = maternal - 70% deletion, 20% mutation
Prader-Willi = paternal - 70% delection, 25% maternal uniparental disomy

Question 33

DiGeorge Syndrome
Genetic cause
Features

Answer 33

Microdeletion at chromosome 22q11
CATCH-22
Cardiac anomaly, abnormal facies, thymic aplasia, hypocalcaemia/hypoparathyroid