Diagnosing aceruloplasminemia: navigating through red herrings.

Abstract

A 58-year-old female was found to have hyperferritinemia (Serum ferritin:1683 ng/mL) during work-up for mild normocytic anemia. Transferrin saturation(TSAT) was low-normal. Magnetic resonance imaging (MRI) abdomen showed evidence of hepatic iron deposition. Liver biopsy showed 4 + hepatic iron deposition without any evidence of steatosis or fibrosis. Quantitative liver iron was elevated at 348.3 µmol/g dry liver weight [Reference range(RR): 3-33 µmol/g dry liver weight]. She was presumptively diagnosed with tissue iron overload, cause uncertain. A diagnosis of ferroportin disease (FD) was considered, but the pattern of iron distribution in the liver, mainly within the hepatic parenchyma (rather than in the hepatic Kupffer cells seen in FD), and the presence of anemia (uncommon in FD) made this less likely. She was treated with intermittent phlebotomy for over a decade with poor tolerance due to worsening normocytic to microcytic anemia. A trial of deferasirox was done but it was discontinued after a month due to significant side effects. During the course of treatment, her ferritin level decreased. Over the past 1.5 years, she developed progressively worsening neurocognitive decline. MRI brain showed areas of susceptibility involving basal ganglia, midbrain and cerebellum raising suspicion for metabolic deposition disease. Neuroimaging findings led to testing for serum copper and ceruloplasmin levels which were both found to be severely low. Low serum copper, ceruloplasmin levels and neuroimaging findings led us to consider Wilson disease however prior liver biopsy showing elevated hepatic iron rather than hepatic copper excluded the diagnosis of Wilson disease. After shared decision making, ceruloplasmin gene analysis was not pursued due to patient's preference and prohibitive cost of testing. The diagnosis of aceruloplasminemia was ultimately made. The biochemical triad of hyperferritinemia, low-normal TSAT and microcytic anemia should raise the possibility of aceruloplasminemia. Since neurological manifestations are rare in most inherited iron overload syndromes, neurological symptoms in a patient with tissue iron overload should prompt consideration of aceruloplasminemia as a differential diagnosis.