[Misdiagnosis of Wilson's disease despite positive genetics]

Nuklearmedizinische Diagnostik beim Morbus Wilson

Wilson's disease is an autosomal recessive disorder of copper metabolism and is caused by a genetic defect on chromosome 13. Nuclear medicine methods can prove the metabolic defect and contribute to the assessment of central neurological deficits.With high specificity and sensitivity, the intravenous radiocopper test enables the diagnosis to be confirmed as the basis for initiating treatment. The oral radiocopper test is used to monitor zinc treatment.[¹²³I]β-CIT-SPECT and [¹²³I]IBZM-SPECT provide functional information of the nigrostriatal system.[¹²³I]β-CIT-SPECT also allows the determination of SERT availability in the hypothalamus/brain stem as a surrogate parameter of depression.Metabolic parameters of the cortex, basal ganglia and cerebellum can be assessed by [¹⁸F]FDG-PET studies.SPECT and [¹⁸F]FDG-PET studies show significant differences between neurological and non-neurological Wilson patients. Overall, only noninvasive in vivo nuclear medicine enables a deeper insight into the pathophysiology of neurological processes in Wilson's disease.

Classification and differential diagnosis of Wilson's disease

Wilson's disease is characterized by hepatic and extrapyramidal movement disorders (EPS) with variable manifestation primarily between age 5 and 45. This variability often makes an early diagnosis difficult. A classification defines different clinical variants of Wilson's disease, which enables classifying the current clinical findings and making an early tentative diagnosis. Until the unequivocal proof or an autosomal recessive disorder of the hepatic copper transporter ATP7B has been ruled out, differential diagnoses have to be examined. Laboratory-chemical parameters of copper metabolism can both be deviations from the norm not related to the disease as well as other copper metabolism disorders besides Wilson's disease. In addition to known diseases such as Menkes disease, occipital horn syndrome (OHS), Indian childhood cirrhosis (ICC) and ceruloplasmin deficiency, recently discovered disorders are taken into account. These include MEDNIK syndrome, Huppke-Brendel syndrome and CCS chaperone deficiency. Another main focus is on differential diagnoses of childhood icterus correlated with age and anaemia as well as disorders of the extrapyramidal motor system. The Kayser-Fleischer ring (KFR) is qualified as classical ophthalmologic manifestation. The recently described manganese storage disease presents another rare metabolic disorder with symptoms similar to Wilson's disease. As this overview shows, Wilson's disease fits into a broad spectrum of internal and neurological disease patterns with icterus, anaemia and EPS.