Liver transplantation for late-onset ornithine transcarbamylase deficiency: A case report

Abstract

Background: Ornithine transcarbamylase deficiency (OTCD) is an X-linked inherited disorder and characterized by marked elevation of blood ammonia. The goal of treatment is to minimize the neurological damage caused by hyperammonemia. OTCD can be cured by liver transplantation (LT). Post-transplant patients can discontinue anti- hyperammonemia agents and consume a regular diet without the risk of developing hyperammonemia. The neurological damage caused by hyperammonemia is almost irreversible.

Case summary: An 11.7-year-old boy presented with headache, vomiting, and altered consciousness. The patient was diagnosed with late-onset OTCD. After nitrogen scavenging treatment and a protein-free diet, ammonia levels were reduced to normal on the third day of admission. Nevertheless, the patient remained in a moderate coma. After discussion, LT was performed. Following LT, the patient's blood ammonia and biochemical indicators stabilized in the normal range, he regained consciousness, and his nervous system function significantly recovered. Two months after LT, blood amino acids and urine organic acids were normal, and brain magnetic resonance imaging showed a decrease in subcortical lesions.

Conclusion: LT can significantly improve partial neurological impairment caused by late-onset OTCD hyperammonemic encephalopathy, and LT can be actively considered when early drug therapy is ineffective.

Keywords: Case report; Hyperammonemic encephalopathy; Liver transplantation; Ornithine transcarbamylase deficiency; Urea cycle disorder.

Figure 1

Blood ammonia changes during the first week of admission.

Figure 2

Brain magnetic resonance imaging. A: On admission, brain magnetic resonance imaging (MRI), T2 fluid attenuated inversion recovery (FLAIR) imaging showed a large symmetrical high signal, more pronounced in the bilateral dorsal thalamus, caudate nucleus, lenticular nucleus, insula, cingulate gyrus and frontal lobe into the cortex at the falx; B: On admission, a high signal was observed on diffusion weighted imaging (DWI) of bilateral dorsal thalamus, caudate nucleus, lenticular nucleus, insula, frontal lobe into the cortex at the falx; C: Two months after liver transplantation (LT), brain MRI, T2 FLAIR imaging showed that the cerebral sulcus fissure was widened and deepened bilaterally in the cerebral hemispheres, and the cortex was atrophied, with a patchy high signal in the frontal lobes bilaterally; D: Two months after LT, brain MRI, DWI did not show any significant abnormal signal, and the abnormal signal in the original bilateral cerebral hemispheric cortex, dorsal thalamus, basal ganglia area, insula, cingulate gyrus, and frontal and temporal lobes was no longer obvious.