Lesch-Nyhan Syndrome

X-linked recessive disorder due to deficiency on the enzyme HGPRT, resulting in the buildup of uric acid

Incidence ∼5.2 per million male births (where symptoms appear)

Hyperuricemia and hyperuricosuria (gout)

Airway problems secondary to scarification from self-mutilation (lip and finger biting)

Involuntary writhing

Repetitive movement of arms and legs

Impairment of renal function due to obstructive uropathy

Aspiration pneumonia (poor muscle control).

May have associated megaloblastic anemia (poorly utilized vitamin B ₁₂ ).

Drug metabolism and prolonged drug effects secondary to metabolic defect and impaired renal function.

Pts are usually mentally subnormal.

Pts exhibit characteristic pattern of compulsive self-mutilation, spasticity, and choreoathetosis.

Primary biochemical defect is almost complete absence of HGPRT.

Enzyme defect leads to excessive purine production and elevated uric acid concentrations.

Genetic disease inherited as X-linked recessive trait (female carriers generally asymptomatic)