Purine salvage deficiencies Flashcards

1
Q

What are the two purine salvage deficiencies?

A

ADA deficiency

Lesch-Nyhan syndrome

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2
Q

Mode of inheritance: ADA deficiency

A

AR

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3
Q

What does HGPRT catalyze?

A

Guanine —> GMP

Hypoxanthine —> IMP

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4
Q

What causes ADA deficiency?

A

Too much ATP and dATP, which causes feedback inhibition of ribonucleotide reductase, thereby inhibiting pyridimidine synthesis, which decreases pool of rapidly-dividing T cells and B cells

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5
Q

What would be elevated in the blood of a kid with Lesch-Nyhan syndrome?

A

Uric acid

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6
Q

Mode of inheritance: Lesch-Nyhan syndrome

A

X-linked recessive

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7
Q

Which drug is activated by HGPRT?

A

6-MP

(inhibits PRPP —> IMP in purine synthesis)

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8
Q

What does xanthine oxidase catalyze?

A

Hypoxanthine –> xanthine

Xanthine –> uric acid

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9
Q

What are the symptoms of Lesch-Nyhan syndrome?

A

Hyperuricemia

Gout

Pissed (agitation, self-mutilation)

Retardation

dysTonia

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10
Q

Which drug produces the same deficiency as ADA deficiency?

A

Hydroxyurea

(Both cause inhibition of ribonucleotide reductase)

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11
Q

What does ADA catalyze?

A

Adenosine —> inosine

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12
Q

What causes Lesch-Nyhan syndrome?

A

HGPRT deficiency, so can’t generate IMP or GMP

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13
Q

How is Lesch-Nyhan syndrome treated?

A

Allopurinol or febuxostat

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14
Q

ADA deficiency is the primary cause of:

A

SCID

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15
Q

Which drug in inactivated by XO (and TMPT)?

A

6-MP

(inhibits PRPP —> IMP in purine synthesis)

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