PATH - Purine salvage deficiencies

Question 1

Adenosine deaminase deficiency

Answer 1

ADA is required for degradation of adenosine
and deoxyadenosine.

In ADA deficiency, INC dATP–>toxicity in lymphocytes

One of the major causes of autosomal recessive
SCID.

Question 2

Lesch-Nyhan syndrome

Answer 2

X-linked recessive

Defective purine salvage due to absent *HGPRT

Results in excess uric acid
production and de novo purine synthesis.

SX: intellectual disability, *self-mutilation,
aggression, hyperuricemia (orange “sand” [sodium urate crystals] in diaper), gout,
dystonia

HGPRT:
Hyperuricemia
Gout
Pissed off (aggression, self-mutilation)
Retardation (intellectual disability)
DysTonia

TX: allopurinol or febuxostat (2nd line).