Wilson's disease; an inborn error of metabolism with multiple manifestations

Biochemical Markers for the Diagnosis and Monitoring of Wilson Disease

Wilson disease (WD) is an autosomal recessively-inherited disorder of copper metabolism and characterised by a pathological accumulation of copper. The ATP7B gene encodes for a transmembrane copper transporter essential for biliary copper excretion. Depending on time of diagnosis, severity of disease can vary widely. Almost all patients show evidence of progressive liver disease. Neurological impairments or psychiatric symptoms are common in WD patients not diagnosed during adolescence. WD is a treatable disorder, and early treatment can prevent the development of symptoms in patients diagnosed while still asymptomatic. This is why the early diagnosis of WD is crucial. The diagnosis is based on clinical symptoms, abnormal measures of copper metabolism and DNA analysis. Available treatment includes chelators and zinc salts which increase copper excretion and reduce copper uptake. In severe cases, liver transplantation is indicated and accomplishes a phenotypic correction of the hepatic gene defect. Recently, clinical development of the new copper modulating agent tetrathiomolybdate has started and direct genetic therapies are being tested in animal models. The following review focuses especially on biochemical markers and how they can be utilised in diagnosis and drug monitoring.

History of Wilson disease: a personal account

This chapter focuses on the historic aspects of the development of much of our current knowledge of the diagnosis and treatment of Wilson disease. Included are descriptions of the clinical signs of neurologic and hepatic disease, the natural history of disease progression, studies of disease pathogenesis and a unique perspective on the development of diagnostic testing and pharmacological therapy.

THE DEPOSITION OF EXOGENOUS COPPER UNDER EXPERIMENTAL CONDITIONS WITH OBSERVATIONS ON ITS NEUROTOXIC AND NEPHROTOXIC PROPERTIES IN RELATION TO WILSON'S DISEASE

Goldfish kept in water containing ionized copper and a detergent added with the aim of decreasing coagulation of the mucus on the gills, took in and retained this metal in their brains, livers, and kidneys, in concentrations comparable to those that occur naturally in Wilson's disease, as chemical assays disclosed. Histochemical studies made it clear that much copper had accumulated within the large neurons, principally in those of the telencephalon and anterior horn region of the spinal cord and in the tubular epithelial cells of the kidneys, the nuclei of the parenchymal cells of the liver, the sarcoplasm of the skeletal muscle, and in the epithelial covering of the gills. The intraneuronal deposition of copper was regularly associated after a time with conspicuous cytologic changes, notably contraction and hyperchromaticity of the nerve cells with tortuosity and fragmentation of the axis cylinders and lysis and loss of neurons. The accumulation of metal in the renal epithelium was frequently accompanied by necrosis and was regularly associated with hyperplasia and calcification of the epithelial cells of the larger renal tubules in all goldfish kept for prolonged periods in copper-rich water. The deposition of copper in the liver was not accompanied by consistent cytologic changes. The similarity of the cytologic alterations induced in the central nervous systems by copper and those that occur naturally in hepatolenticular degeneration in human beings provides evidence that copper itself plays an important role in the pathologic alterations of the brain in Wilson's disease.

Chapter 33: the history of movement disorders

Role of basal ganglia: Vesalius and Piccolomini distinguished subcortical nuclei from cortex and white matter in the 16th century. Willis' mistaken concept in the late 17th century that the corpus striatum was the seat of motor power persisted for 200 years and formed the basis of mid-19th-century localizations of movement disorders to the striatum (chorea by Broadbent and Jackson, and athetosis by Hammond). By the late 19th century, many movement disorders were described but for most no pathologic correlate was known. Tremor: Descriptions of tremors progressed from Galen's definition in the 2nd century; to Galileo's physiologic tremor in 1610; separation of involuntary movements during action and at rest in the 17th and 18th centuries by de la Boë Sylvius and van Sweiten; description of Parkinson's disease by Parkinson, discrimination of the rest tremor of Parkinson's disease from the intention tremor of multiple sclerosis by Charcot, and recognition of familial action tremors by Dana and others in the late 19th century; and recognition of autosomal dominant essential tremor in the mid-20th century. Parkinsonism: Pathologic changes in Parkinson's disease were recognized in the substantia nigra by Blocq and Marinescu in the late 19th century, and around 1920 Trértiakoff established Lewy bodies in the substantia nigra as a pathologic hallmark while the Vogts instead emphasized pathologic changes in the striatum; it was only in the mid-1960s that a nigrostriatal dopaminergic pathway was demonstrated and found to be critical to pathogenesis. Early treatment approaches with anticholinergic medications or crude neurosurgical ablation procedures were eclipsed in the 1960s by the advent of L-DOPA therapy due to the work of Carlsson and colleagues, Birkmayer and Hornykiewicz, Barbeau, and Cotzias. Later progress in understanding and treating Parkinson's disease included recognition of neuroleptic-induced parkinsonism beginning in the 1950s, development of dopamine agonists and elaboration of different dopamine receptors beginning in the 1960s, recognition of MPTP-induced parkinsonism in 1982 and subsequent development of experimental models of MPTP-induced parkinsonism. Since the 1980s, stereotactic neurosurgical ablation procedures such as stereotactic pallidotomy were revisited and improved, and stimulation or ablation procedures that modulate subthalamic nucleus activity were developed. Since 1990, rare genetic forms of Parkinson's disease were discovered, which accelerated progress in understanding pathogenesis, and established roles for alpha synuclein and the ubiquitin-proteasome proteolytic system. Separation of atypical forms of parkinsonism (e.g. Wilson's disease, multisystem atrophy, progressive supranuclear palsy, and corticobasal degeneration) from Parkinson's disease in the 20th century also led to important discoveries of basal ganglia function, and in the case of Wilson's disease to recognition of genetic mutations and effective treatments. Choreoathetosis: Since the middle ages, the term chorea has been used to describe both organic and psychological disorders of motor control. Paracelcus introduced the concept of chorea as an organic medical condition in the 16th century. Sydenham's description of childhood chorea (1686) was followed by recognition in the 19th and 20th centuries that Sydenham's chorea was a manifestation of rheumatic fever; by the 1930s, rheumatic fever was recognized as a sequel of group A streptococcal pharyngitis, which could be effectively prevented with sulfonamides. Athetosis was described by Hammond (1871) and later linked by him to a malignant growth in the contralateral corpus striatum; nevertheless, athetosis has been controversial and often dismissed as a form of post-hemiplegic chorea or part of a continuum between chorea and dystonia. Huntington's classic description of adult-onset hereditary chorea (1872) was followed a century later by demonstration that Huntington's disease is caused by an unstable CAG trinucleotide repeat expansion in the Huntington disease gene on chromosome 4; this triggered a surge in research, development of various animal models, and numerous important discoveries of cell function and disease pathogenesis. Hemiballismus and the subthalamic nucleus: The relationship between a lesion of the subthalamic nucleus of Luys and contralateral hemiballismus was first convincingly demonstrated by Martin in 1927; this led 20 years later to development of an animal model by Whittier and Mettler, who produced experimental hemichorea-hemiballismus in monkeys by lesioning the contralateral subthalamic nucleus. Since the late 1980s, the neurochemistry and neurophysiology of the subthalamic nucleus have been substantially revised with the demonstration that the subthalamic nucleus is not fundamentally inhibitory but instead provides excitatory glutaminergic inputs to the globus pallidus, and appreciation that the subthalamic nucleus serves an important role in both hyperkinetic and hypokinetic movement disorders. Dystonia: Dystonias were often interpreted in psychological or psychiatric terms since the original descriptions of generalized dystonia by Barraquer Roviralta (1897), and familial forms of generalized primary tortion dystonia by Schwalbe (1908) and Oppenheim (1911). Although Oppenheim had first insisted that dystonia was an organic disease, it was only in the late-20th century that an organic framework was firmly established with the identification of genetic mutations in some families with dystonia and with the demonstration that the basal ganglia were often damaged contralateral to acquired hemidystonia. Focal and segmental forms of dystonia, including writer's cramp, other occupational dystonias, and torticollis, were also recognized in the 19th century. Writer's cramp was clearly described in the 1830s by Bell and Kopp, and increasingly recognized in the late 19th century due in part to Solly's influential lectures on "scriviner's palsy" in the 1860s, and to increasing prevalence because of the increase in writing using primitive writing instruments. Myoclonus: In 1903, Lundborg proposed a classification of myoclonus that remains in use, with primary (essential), epileptic, and secondary or symptomatic categories: essential myoclonus was described by Friedrich in 1881; forms of myoclonic epilepsy were described beginning in the late 19th century by West (1861), Unverricht (1891), and Lundberg (1903); and secondary multifocal myoclonus was recognized in a wide variety of disorders beginning in the 1920s. Asterixis was described in patients with hepatic encephalopathy by Adams and Foley in 1949 and found to result from electrically silent pauses in muscle activity, which led to the concept of negative myoclonus in the 1980s. Posthypoxic action myoclonus (Lance-Adams syndrome) was described by Lance and Adams in 1963 and found to incorporate both positive and negative components. Startle syndromes: Early descriptions of pathologic startle syndromes included Beard's description of the jumping Frenchmen of Maine (1878) and Hammond's description of miryachit (1884), both of which may have had psychological origins. In contrast, hyperekplexia or "startle disease" was described in the late 1950s and early 1960s, and genetic forms were later found to result from various mutations affecting glycinergic synapses. Tics: Tic disorders were described by Itard (1825) and Trousseau (1873), but only gained wider recognition in the late 19th century after Charcot presented cases before his classroom audiences and after Gilles de la Tourette's classic description in 1885. Gilles de la Tourette and Charcot initially considered tic disorders and startle syndromes to be similar if not identical, but these disorders were later recognized as distinct. Psychodynamic and psychological theories or etiology gave way in the 1960s to biological theories supporting an important role for dopamine in pathogenesis, particularly with the discovery that neuroleptic medications could be useful in treatment.

CONCLUSION

In the last two centuries, neuroscientists and clinicians contributed greatly to our understanding of basal ganglia anatomy and physiology, as well as to movement disorder semiology, pathophysiology, treatment, and prevention. The development of animal models, and the increasing use of genetic and molecular biological techniques will lead to further advances in the coming years.

Immunocytochemical identification of caeruloplasmin in hepatocytes of patients with Wilson's disease

Decreased serum caeruloplasmin levels in patients with Wilson's disease have been attributed to decreased caeruloplasmin synthesis in the hepatocyte. An immunoperoxidase procedure was used to identify caeruloplasmin in liver biopsies. The pattern of staining in biopsies from patients with Wilson's disease did not differ from the pattern seen in normal adult or neonatal liver. This indicates that immunoreactive caeruloplasmin is synthesized by the liver cell in Wilson's disease. Low serum levels of caeruloplasmin may reflect an abnormality of copper incorporation into the apoprotein or an abnormality of holocaeruloplasmin export.

Renal stones in Wilson's disease

Fifty-four patients with Wilson's disease were studied with regard to renal stones. Seven of the 45 patients (16 per cent) who underwent roentgenographic procedures of the urinary tract had unequivocal evidence of renal stones. In four of the seven patients with Wilson's disease who had renal stones, the stones were discovered at the time or before the diagnosis of Wilson's disease was made. Of the several possible factors that may predispose patients with Wilson's disease to renal stone formation, the renal tubular acidosis pattern of abnormality in acid-base excretion is probably the most significant. In general, patients with renal stones and unexplained neurologic, bony or hepatic abnormalities should be screened for Wilson's disease by slit-lamp examination, determination of serum copper and ceruloplasmin concentrations, and urinary excretion of copper, particularly if they have relatively alkaline urine.

Degeneração hepatolenticular: conteúdos de ferro e cobre em tecidos de material de autópsia

Os autores apresentam os resultados das dosagens de ferro e cobre nos tecidos de um paciente com degeneração hepatolenticular, no qual a moléstia teve curso fulminante. Parece que o curso da moléstia foi agravado pela administração de drogas tranqüilizantes quando foi iniciado o tratamento com penicilamina. Esta observação pode ser de interesse clínico. Os teores de cobre e ferro estavam muito aumentados nos tecidos cerebrais, no fígado, nos pulmões, nos rins, no baço, na suprarenal e em outros órgãos.

Degeneração hepatolenticular

Após reverem os marcos fundamentais da história da moléstia de Wilson, os autores relatam 3 casos desta afecção. Dois pacientes faleceram, tendo o exame necroscópico confirmado o diagnóstico clínico-laboratorial. Entre as particularidades do quadro neurológico, sobressaía, em um caso, a existência de espasticidade em flexão e de sinais cerebelares. O anel corneano de Kayser-Fleischer apresentou-se sempre completo e bilateral. Entre os caracteres inconstantes do proteinograma do líquido cefalor-raqueano são salientadas a ausência de pré-albumina e os baixos níveis de globulinas 1 e 2. Provàvelmente pela primeira vez, foi observada redução dos valôres de fósforo e magnésio no sôro sangüíneo. O estudo das funções hepática e renal foi realizado por meio dos testes convencionais, tendo-se verificado que o comprometimento do fígado era discreto, em nítida desproporção com o grau de lesão histológica do órgão (cirrose pós-necrótica). Em relação aos rins, foi comprovada hiperaminacidúria em dois casos, associada a discreta diminuição da excreção tubular, em um deles. A análise genética pôde ser mais aprofundada em um dos casos, incluindo a pesquisa, nos seus familiares, do anel de Kayser-Fleischer, a determinação dos valôres de cobre no sangue e urina, e da ceruloplasminemia, além do estudo citogenético do paciente. O anel corneano foi comprovado em uma irmã assintomática, ocorrendo nela e em outros parentes nítidas alterações do metabolismo do cobre. O estudo do conteúdo de cobre nos tecidos confirmou os dados da literatura quanto ao acúmulo desse metal no pancreas, rins, supra-renais, fígado, substâncias branca e cinzenta do cérebro, tálamo, córtex cerebelar e núcleo lentículo-caudado, assim como níveis normais nas unhas e baixos nos cabelos. Verificação provàvelmente inédita foi o achado de acúmulo de cobre na substância negra e núcleo rubro, assim como nas glândulas submandibulares e no cerume. No líquido cefalorraqueano os valôres do cobre total se encontravam dentro dos limites normais e muito próximos dos do cobre de reação direta. Na bile, de acordo com as referências da literatura, observamos concentração de cobre normal na bile total e na fração B, e valôres diminuídos nas biles A e C. Em todos os casos verificou-se diminuição da concentração de cobre e ceruloplasmina no sangue e elevação dos valores na urina e saliva. O cobre de reação direta do soro, determinado em um caso, mostrou-se em nível relativamente alto. O estudo dos balanços metabólicos demonstrou positividade para o cobre nos períodos de contrôle, e discreta negatividade do balanço do fósforo. Após o emprego do BAL, e particularmente da D-penicilamina, o balanço do cobre se negativou e o do fósforo tornou-se mais acentuadamente negativo. Dieta hipocúprica, resinas permutadoras de cations ou sulfeto de potássio foram associados aos agentes complexantes. A melhora clínica, embora nítida no caso 3 após o uso de D-penicilamina e estrógenos, não correspondeu ao excelente resultado bioquímico.