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Medical Genetics Review Course > Screening and Multi-factorial Inheritance/Complex disorders > Flashcards

Screening and Multi-factorial Inheritance/Complex disorders Flashcards

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1
Q

The % empiric recurrence risk for a multifactorial/complex trait in

  • First degree relative
  • Second degree relative
  • Third degree relative
A
  • 3.2
  • 0.5
  • 0.17
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2
Q

The recurrance risk in a first degree relative is approx the _____ ________ of the population incidence

A
  • Square root
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3
Q

Traits with male sex bias include (5)

A
  1. Pyloric stenosis
  2. Hirsprung Disease
  3. CL +/- CP
  4. Legg Calves Perthe Disease
  5. Club foot
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4
Q

Traits with a female sex bias (3)

A
  1. Congenital hip dislocation
  2. Cleft palate
  3. Open neural tube defects
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5
Q

In multifactorial traits most affected children have ______parents

A

unaffected

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6
Q

In multifactorial traits recurrence risk ________ with the number of affected children in the family

A

increases

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7
Q

Recurrence risk _____ with the severity of the defect, in multifactorial defects

A

increases

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8
Q

If a population has a higher incidence of a disorder, the recurrance risk is _______ in that population

A

higher

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9
Q

Consanguinity ________ increases the risk for an affected child in multifactorial traits

A

slightly

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10
Q

If two sexes have a different probability of being affected, the _____________ if affected, is the most likely to produce an affected offspring

A

least likely sex

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11
Q

A disorder affects males twice as often as females. Which offspring has the highest risk of being affected?

A

The son of affected female

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12
Q

Definition: number of affected individuals** who test positive for the disease out of the total number of **affected individuals

A

Sensitivity

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13
Q

Definition: the number of unaffected individuals** who have a **negative test** result out of the total number of **unaffected individuals

A

Specificity

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14
Q

1-Specificity

A

False Positive Rate: the fraction of unaffected individuals who screened positive

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15
Q

1-sensitivity

A

False negative rate: number of affected individuals with a negative screen

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16
Q

What happens when we screen in a population with decrease disease incidence?

You will have a decrease in what values

A
  • PPV
  • True positives
  • False negatives
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17
Q

What happens when we screen in a population with decrease disease incidence?

You will have a increase in what values

A
  • NPV
  • True negatives
  • False positives
18
Q

Evevation of the following on newborn screen is suggestive of what condition?

C0/C16+C18

A

CPT 1 deficiency

carnitine palmitoyl transferase 1 deficiency

prevents the fatty acid carnitine-acylcarnitine linkage required to transport fatty acids into the mitochondria

this results in accumulation of free carnitine (C0) and prevents the fatty acid oxidation response neccessary to generate energy during fasting and increased energy needs

19
Q

Evevation of the following on newborn screen is suggestive of what condition?

C16 and or C18:1

A

CPT 2/ CACT deficiency

Carnitine Palmitoyltransferase 2 deficiency

20
Q

Evevation of the following on newborn screen is suggestive of what condition?

C4;C5

A

Glutaric acid 2/ Ethylmalonic encephalopathy

MADD- multiple acyl-CoA dehydrogenase deficiency

21
Q

Evevation of the following on newborn screen is suggestive of what condition?

C16-OH +/- C18:1-OH

A

Long Chain Hydroxyacyl-CoA Dehydrogenase deficiency (LCHAD)

Trifunctional Protien D (TFP)

22
Q

Evevation of the following on newborn screen is suggestive of what condition?

C8; C6, C10

A

Mediun chain AcylCoA Dehydrogenase deficiency (MCAD)

23
Q

Evevation of the following on newborn screen is suggestive of what condition?

C14:1

A

Very long chain acylCoA dehydrogenase Deficiency (VLCAD)

24
Q

Newborn Screening

May or may not be detected on acylcarnitine analysis C5-OH

Clinical features: Neurological (Seizures), dermatitis, hypotonia, alopecia, conjuctivitis

Condition and Treatment?

A

Biotinidase Deficiency

Tx: Biotin

25
Q

Newoborn Screening

Organic acid analyte

Glutaric Acidemia type 1

A

C5-DC

26
Q

Newoborn Screening

Organic acid analyte

Isovalaric acididemia

A

C5

27
Q

Newoborn Screening

Organic acid analyte

Malonic Acidemia

A

C3-DC

28
Q

Newoborn Screening

Organic acid analyte

Methylmalonic and Proprionic aciduria

A

C3

29
Q

Newborn Screening

Low GALT

Elevated galactose-1 phosphate or Galactose

What symptoms would you expect in an untreated infant

A

Classic Galactosemia

  • Feeding difficulty
  • Failure to thrive
  • Liver Failure
  • Bleeding
  • E.Coli sepsis
30
Q

Maternal serum screening

only marker used to calculate NTD risk

A

AFP

31
Q

Maternal Serum Screening

Weighted most heavily in calculated Down Syndrome Risk

A

Human Chorionic Gonadotropin (hCG)

32
Q

Maternal Serum Screening Pattern

High MSAFP

Normal hCG

Normal uE3

Normal Inhibin-A

A

Neural Tube Defect/Anencephaly

33
Q

Maternal Serum Screening Pattern

Low MSAFP

High hCG

Low uE3

High Inhibin-A

A

Down Syndrome

34
Q

Maternal Serum Screening Pattern

Low MSAFP

Low hCG

Low uE3

Low Inhibin-A

A

Trisomy 18

35
Q

Maternal Serum Screening Pattern

Normal MSAFP

Normal hCG

Very low/Undetectable uE3

Normal Inhibin-A

A

Steroid Sulphatase Deficiency/ Smith Lemil Opitz

36
Q

For MSAFP

3-4.9 MoM

the risk for poor outcome is

A

about 41%

37
Q

For MSAFP

>5MoM

the risk for poor outcome is?

A

about 91%

38
Q

For MSAFP

what MoM value is mostle used for screen positive individuals

and of these woman screened positive what % will have a NTD or open abdominal wall defect

A

2.5 MoM

which translated to about 2-3% of woman screened

of these about 10% will have a NTD or ventral wall defect

39
Q

Reasons for false positive NIPs

A
  • Placental mosaicism
  • Vanishing twin
  • Maternal mosaism
  • Maternal malignancy
40
Q

Reason for failed NIPs

A
  • Low fetal DNA (Can be a sign of aneuploidy)
  • High maternal BMI
  • Early gestational age (should not be performed beofre 9-10 wks)

Medical Genetics Review Course (11 decks)

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