Repeated USMLE Questions Step 1- 280

A 4-year-old boy is brought to his physician by his mother. She is worried and tells you that her son is weak and not growing properly. He chews his fingers and lips constantly and seems to enjoy it. On examination, there is marked loss of tissues on his fingers and lips. His serum and urine levels of uric acid are both high.

What is the most likely diagnosis of this condition?

A-Gaucher disease

B-Hurler syndrome

C-Lesch-Nyhan syndrome


E-Tay-sachs disease


This is a typical presentation of Lesch-Nyhan syndrome which is caused by hypoxanthine-guanine phosphoribosyltransferase (HGPRT) enzyme deficiency. Elevated serum and urine uric acid concentrations accompanied by self-mutilating behaviors are diagnostic of this condition.

The correct answer is C

2 thoughts on “Repeated USMLE Questions Step 1- 280”

  1. Thank you Donna

  2. Lesch-Nyhan syndrome

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