Genetic and Metabolic Medicine Flashcards

1
Q

Single copy of a set of chromosome

A

Haploid

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2
Q

Three copies of a set of chromosome

A

Triploid

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3
Q

Three copies of a single chromosome within a whole cell

A

Trisomy

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4
Q

Define lyonisation

A

One of the two X chromosomes in every cell in a female is randomly inactivated early in embryonic development. - forms a Barr body

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5
Q

Characteristics of X-linked dominant conditions

A

both sexes affected equally, often lethality in males and females less affected

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6
Q

Explain trinucleotide repeat disorders with examples

A

Increasing numbers of repeats (show anticipation) eg) Myotonic dystrophy, Fragile X, Friedrichs Ataxia

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7
Q

What is MELAS?

A

Mitochondrial Encephalopathy, Lactic Acidosis and stroke like episodes = mitochondrial inheritance

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8
Q

What is MERRF?

A

Myoclonic epilepsy with Raggad Red Fibres = mitochondrial inheritance

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9
Q

Tissues usually affected by mitochondrial disorders?

A

All tissues requiring a lot of energy (Brain, eyes, ears, kidneys)

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10
Q

What is genomic imprinting? + Disorders

A

Epigenetic phenomenon leading to the exclusive expression of specific genes from only one parent. Disease = uniparental disomy (maternal) - Ch 15 Prader-Willi (paternal) - Ch 15 Angelmans

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11
Q

Genetic syndromes associated with peripheral pulmonary stenosis? (x 2)

A

Alagile syndrome, Williams syndrome

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12
Q

Genetic syndrome associated with Tetralogy of Fallot? (+ characteristics x 7)

A

Velocardiofacial Syndrome ~ DiGeorge Sx - 22q11 deletion - Tetralogy of Fallot - Cleft palate - Long face - Bulbous nose, abnormal ears - Short palpebral fissures - learning difficulty

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13
Q

Genetic Syndrome associated with pulmonary stenosis? (+ other characteritstics

A

Noonan Syndrome

  • broad webbed neck
  • wide set eyes
  • ptosis + epicanthic folds
  • Micrognathia
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14
Q
A
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15
Q

What is propionic acidaemia?

A

Rare metabolic disorder, affects all tissues

Increased risk of metabolic stroke (in basal ganglia) due to toxic metabolites due to deficiency in enzyme importat for protein breakdown

Seizures/encephalopathy, hypotonia, cardiomyopathy, pancreatitis, vision/hearing loss

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16
Q

Neonatal jaundice, feeding difficulties, developmental delay, cataracts?

A

Galactosaemia

  • caused by RBC galactose-1-phosphate (GALT) deficiency
  • Unable to breakdown galactose
  • picked up on newborn screen
  • avoidance of galactose reduces developmental delay, can cause cataracts
17
Q

Gross motor regression at >3 months, macrocephally, cherry red macular, hyper-reflexia?

A

Tay-Sachs Disease

  • lysosomal storage disorder from Chr 15 (AR)
  • macrocephaly due to accuulation of GM2 in the brain and progressive neurological decline
  • more common in Ashkenazi Jewish or French-Canadian descent
18
Q

What is a mucopolysacharidosis?

+ 3 main types

A

Defect in enzymes that break down GAGs (glycosaminoglycans) - defects due to accumulation of breakdown products

1) Hunters (MPS II - X-Rescessive) - normal vision, GDD, sinopulmonary infections, hepatosplenomegally
2) Morquio (MPS IV) - skeletal problems + cloudy cornea, normal intellect
3) Hurlers (MPS I)- GDD, sinopulmonar infections, hepatosplenomegally, cloudy cornea