Biochem - Genetics (Part 2) Flashcards Preview

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Flashcards in Biochem - Genetics (Part 2) Deck (115)
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31

In Leber's hereditary optic neuropathy, vision loss is _____ (central/peripheral).

Central

32

Autosomal-dominant patterns of inheritance are often found in diseases caused by defects in _____ genes.

Structural; as opposed to recessive diseases, which are often caused by faulty enzyme genes

33

True or False: A mother with an X-linked dominant disease may pass the disease only to her sons.

False; both her sons and her daughters may be affected

34

True or False? Patients with autosomal-dominant disorders often present clinically after puberty.

True; in order for the diseases to remain in the population, affected people must have offspring

35

What is the pattern of inheritance of hypophosphatemic rickets?

X-linked dominant

36

What is the mode of inheritance if a disease is present in many generations and affects both males and females in roughly equal proportions?

Autosomal dominant

37

What is the mode of inheritance in a family in which a disease is transmitted only through the mother and all children (both boys and girls) are affected?

Mitochondrial inheritance

38

Autosomal-recessive patterns of inheritance are often found in diseases caused by defects in _____.

Enzymes; as opposed to dominant diseases, which are often caused by faulty structural genes

39

True or False? A mother may pass a disease with a mitochondrial pattern of inheritance to both her sons and her daughters.

True

40

What is the mode of inheritance if a gene is present in a single generation and 25% of the offspring from the same two parents have the disease?

Autosomal recessive

41

What is the pattern of inheritance of Leber's hereditary optic neuropathy?

Mitochondrial inheritance

42

Do patients with dominant or recessive diseases generally present at a younger age?

Autosomal-recessive diseases

43

What would you expect to see on urinalysis in a patient with hypophosphatemic rickets?

You would expect an increased urine phosphate level since there is proximal tubule phosphate loss

44

Variable expression of mitochondrial diseases can be accounted for by what phenomenon?

Heteroplasmy

45

True or False? Hypophosphatemic rickets can be treated by vitamin D supplementation.

False; this disease is also known as vitamin D-resistant rickets

46

What is the mechanism of phosphate wasting in hypophosphatemic rickets?

There is increased phosphate wasting at the proximal renal tubule

47

Which cells are affected in Leber's hereditary optic neuropathy?

There is degeneration of retinal ganglion cells and their axons

48

In general, are autosomal dominant or autosomal-recessive disorders more severe?

Autosomal recessive

49

What is the mode of inheritance in a family in which 50% of sons are affected and there is no male-to-male transmission?

X-linked recessive

50

What percentage of sons of a carrier mother are expected to inherit an X-linked recessive disease?

50%

51

True or False? X-linked recessive diseases are commonly more severe in males than in females.

True

52

True or False? A mother with an X-linked dominant disease may pass the disease to either her sons or her daughters.

True

53

True or False? A father with an X-linked dominant disease will pass the disease to all of his daughters but none of his sons.

True

54

A mother with achondroplasia is pregnant; assuming that the father does not have this condition, what is the likelihood that her child will also have the disease?

50%; achondroplasia is an autosomal-dominant disease

55

Achondroplasia is the result of a defect in the _____ receptor.

Fibroblast growth factor 3

56

Describe the clinical manifestations of achondroplasia.

Patient has dwarfism with short limbs but a normally sized head and trunk

57

What parental attributes are associated with achondroplasia?

Advanced paternal age

58

What is the mode of inheritance of autosomal-dominant polycystic kidney disease?

Autosomal dominant

59

Autosomal-dominant polycystic kidney disease is associated with what cardiac pathology?

Mitral valve prolapse

60

A 50-year-old man has hematuria, hypertension, and progressive renal failure. His kidneys are both massively dilated as a result of multiple large cysts. What is the most likely diagnosis?

Autosomal-dominant polycystic kidney disease