Inherited Liver Diseases: Wilson Disease

0:00Welcome to Board Pearls. This is episode two of three of the Inherited Liver Diseases chapter, in the Liver Disease module. This episode is Wilson disease: low ceruloplasmin and high urinary copper, the Leipzig score, and chelator-plus-zinc therapy. Where hemochromatosis was a failed iron brake, Wilson is a failed copper exit, and the diagnostic logic is harder because no single test stands alone.

0:25It's autosomal recessive ATP7B dysfunction, with hundreds of mutations and one most common in European descent, most patients being compound heterozygotes, and the gene encoding a pump in the hepatocyte that does two coupled jobs, transporting copper into bile for excretion and loading copper onto apoceruloplasmin to make circulating ceruloplasmin. Both fail when the pump is dysfunctional: biliary export collapses so copper accumulates in the hepatocyte and spills into circulation, and the uncoppered apoceruloplasmin is degraded fast, which is the molecular reason serum ceruloplasmin runs low, a consequence of accelerated degradation of the unfilled protein, not a synthetic defect. The tissue damage is oxidative, producing steatosis, a mitochondrial injury pattern, and the Coombs-negative hemolysis that follows acute copper release, and copper accumulates first in the liver, then spills into brain, kidney, and red cells, deposits at Descemet's membrane as Kayser-Fleischer rings, and in the lens as sunflower cataracts. The age of presentation reflects accumulation, with hepatic disease presenting in the early teens and neurologic disease around twenty, so hepatic injury can precede neuropsychiatric symptoms by a decade, and you consider Wilson in any patient from about three to forty-five with unexplained liver disease.

1:42The hepatic phenotypes span the spectrum, asymptomatic transaminitis, chronic hepatitis, young cirrhosis, and fulminant failure with hemolysis, and liver cancer is rare even with advanced fibrosis, which distinguishes Wilson cirrhosis from hemochromatosis, because copper-driven injury doesn't build the same oncogenic field. The board trap is the young patient who looks like metabolic fatty liver without insulin resistance, so a young patient with steatohepatitis but no metabolic syndrome features should prompt a Wilson workup, exploiting the biopsy overlap, since Wilson shows steatosis, glycogenated nuclei, and Mallory hyaline like steatohepatitis. The neuropsychiatric phenotype is its own pattern, the characteristic wing-beating tremor, dysarthria, parkinsonism, and mood or personality change, and in children new poor school performance, with a broad systemic picture including renal tubular dysfunction with a Fanconi syndrome from copper deposition in the tubule, and the high-suspicion fingerprints are liver disease plus new neurologic or psychiatric symptoms, and acute hepatitis with Coombs-negative hemolysis.

2:46Diagnosis requires at least two of five features: Kayser-Fleischer rings on slit lamp, a ceruloplasmin under twenty, typical neurologic symptoms, a twenty-four-hour urinary copper over forty with most symptomatic patients over a hundred, and a hepatic copper over two hundred fifty on biopsy, and the Leipzig score integrates these with weighted features, with four or higher establishing the diagnosis, three making it possible, and two or lower unlikely, and the score exists because no single test is sensitive or specific enough, with ceruloplasmin alone having poor predictive value in both directions. Serum free copper, estimated as total minus a multiple of the ceruloplasmin, runs high in symptomatic disease and is most useful when ceruloplasmin is ambiguous, and the hard exclusions sit at the extremes, a ceruloplasmin over thirty essentially excluding Wilson because synthetic capacity is intact, and a hepatic copper under thirty-five excluding it because copper is the proximate injurious agent, with the intermediate band triggering molecular testing. Low ceruloplasmin isn't specific, also occurring in malabsorption, synthetic failure, carriers, and the X-linked copper-deficiency disease Menkes, so a low value alone tells you little, and quantitative hepatic copper is the gold standard, with the copper stain neither sensitive nor specific because distribution is heterogeneous, and electron microscopy showing abnormal mitochondria highly specific when present.

4:04The fulminant Wilson fingerprint has to be memorized as a coherent pattern, because the misdiagnosis costs the transplant window, and it has six mechanistic pieces: an alkaline-phosphatase-to-bilirubin ratio under four because the injury isn't cholestatic, a low uric acid because tubular dysfunction impairs urate reabsorption, an AST-over-ALT ratio over two with values under two thousand because the injury is mitochondrial, a Coombs-negative hemolysis from copper oxidatively damaging red cells, splenomegaly, and a vitamin-K-unresponsive coagulopathy with progressive renal failure. And Kayser-Fleischer rings are present in nearly all neurologic and psychiatric Wilson but only about half to two-thirds of pure hepatic disease, so their absence doesn't exclude it and slit-lamp isn't a screening test alone. Family screening uses the one-in-four sibling risk with ceruloplasmin, slit-lamp, and targeted genetic testing.

4:54Treatment chooses each agent for the speed and site of copper movement, and the wrong choice in symptomatic neurologic disease causes paradoxical worsening. First-line chelation is trientine, paired with zinc for maintenance and a low-copper diet excluding shellfish, organ meats, nuts, chocolate, and mushrooms, and it's preferred over penicillamine for better tolerability and a much lower rate of paradoxical neurologic worsening, up to half with penicillamine. The mechanistic difference is that penicillamine mobilizes copper aggressively from peripheral tissues including brain, transiently raising brain copper, while trientine produces a slower, more controlled egress, which is why it's preferred for neurologic Wilson, dosed a few times a day on an empty stomach. Trientine carries two interaction traps: it chelates oral iron into a toxic complex so iron supplements aren't co-administered, and it chelates zinc so the two are separated in time, and overtreatment produces a reversible sideroblastic anemia from copper depletion because copper is required for heme synthesis. Penicillamine remains effective but more side-effect-laden, dosed before meals, with a broad testable side-effect set including nephrotic-range proteinuria, a lupus-like reaction, marrow toxicity, and impaired wound healing through inhibition of collagen cross-linking, and pyridoxine is co-prescribed because penicillamine depletes vitamin B6, whereas trientine doesn't. Zinc occupies a different niche, not chelating circulating copper but inducing metallothionein in enterocytes that binds dietary copper preferentially and sheds it in stool, dosed three times daily, with many patients getting GI side effects, and its urinary copper goal signals ongoing unloading, but its slow onset and lack of mobilization make it adequate as maintenance after de-coppering or as monotherapy in pre-symptomatic screen-detected patients, not for symptomatic disease. Long-term therapy is monitored with the twenty-four-hour urinary copper, and when it's low, the free copper distinguishes the two failure modes: high free copper with low urinary copper means non-adherence because copper is circulating but not excreted, while low free copper means overtreatment because copper has been depleted. Liver transplant is curative for the hepatic phenotype because the donor liver carries functioning ATP7B, and it's the rescue for fulminant disease and medical-failure cirrhosis, though transplant for isolated neurologic disease is controversial because the neurologic disease doesn't reliably improve.

7:22Pregnancy is its own problem: chelation is continued at reduced doses, typically a quarter-to-half reduction by the third trimester, driven by two competing pressures, the fetus needing adequate copper and high-dose chelation impairing collagen cross-linking needed for wound healing at delivery, but abandoning chelation entirely isn't safe because maternal flare is the larger risk. Women on trientine may need iron supplementation because it chelates iron, untreated disease causes infertility so pre-conception chelation is itself a fertility intervention, and the offspring risk with a non-carrier partner is about half a percent. Three traps are tested: estrogen-containing contraceptives interfere with biliary copper excretion and are avoided, copper-containing IUDs introduce a continuous copper source and are avoided, and standard prenatal vitamins often contain copper and are replaced with copper-free formulations.

8:17So Wilson in one line: a failed copper exit, the pump unable to push copper into bile or onto ceruloplasmin, copper building in liver and spilling into brain, cornea, kidney, and red cells, diagnosed by an integrated score because no single test is sensitive enough, and treated with trientine over penicillamine to control the speed and site of copper movement, with zinc as maintenance and dose reductions in pregnancy. Taken together with hemochromatosis, the two are a pair of inherited metal-handling failures producing parenchymal injury through metal-driven oxidative damage, each with a biochemical screen, a genetic confirmation, and a removal or depletion strategy, diverging only at the molecular lesion, and both cured by transplant because the donor liver carries the functioning gene.

9:04The next episode covers the other inherited liver diseases beyond the metal pair: alpha-one antitrypsin deficiency with its characteristic globules and genetics, cystic-fibrosis-associated liver disease in patients on modulator therapy, polycystic liver disease with somatostatin-analog therapy, and the pediatric cholestasis spectrum where the bile-acid-transporter inhibitors changed management.

9:27For the full chapter, the practice vignettes, and the topic-tagged question bank, head to board pearls dot com. You'll find the rest of the series on Apple Podcasts, Spotify, or wherever you listen to podcasts. That brings us to the end of episode two of three of chapter twenty-two, and I'll see you in the next one.