Heterozygote ornithine transcarbamylase deficiency presenting as symptomatic hyperammonemia during initiation of valproate therapy.
Ornithine transcarbamylase is a mitochondrial urea cycle enzyme. Women with heterozygous ornithine transcarbamylase deficiency may have no symptoms or have episodic, symptomatic hyperammonemia, which can be fatal. We report a previously undiagnosed heterozygote ornithine transcarbamylase-deficient patient who had symptomatic hyperammonemia during initiation of valproate therapy. This is the second such patient reported. Symptomatic hyperammonemia during valproate therapy may indicate ornithine transcarbamylase deficiency. Since valproate inhibits ureagenesis and can be toxic to mitochondria, it should be used extremely cautiously, or not at all, in ornithine transcarbamylase-deficient patients.
Honeycutt
D
D
Department of Neurology, University of Alabama, Birmingham Medical School 35294.
Callahan
K
K
Rutledge
L
L
Evans
B
B
D000328:Adult; D000641:Ammonia / Q000097:blood*; D005260:Female; D006579:Heterozygote; D006801:Humans; D008659:Metabolic Diseases / Q000209:etiology* / Q000235:genetics / Q000378:metabolism; D020163:Ornithine Carbamoyltransferase Deficiency Disease; D012640:Seizures / Q000188:drug therapy; D014635:Valproic Acid / Q000009:adverse effects* / Q000627:therapeutic use
D014635:Valproic Acid; D000641:Ammonia