Identification of crossovers in Wilson disease families as reference points for a genetic localization of the gene

Case report: concordant traumatic brainstem contusion delayed diagnosis in a young man with Wilson's disease

Wilson's disease is a hereditary autosomal recessive disorder of copper metabolism. The corresponding gene locus has been localized on the long arm of chromosome 13. Three different clinical variants of the disease can be distinguished: hepato-cerebral, abdominal/hepatic, and central nervous type. The heterogeneity of symptoms can cause problems in differential diagnosis, especially when another concordant disorder can also explain the pathogenesis of symptoms. The case report of a young man who suffered from brainstem contusion demonstrates the possibilities of misinterpretation because presenting symptoms could be attributed either to traumatic brain injury followed by adjustment disorder or Wilson's disease. Clinical signs included leftsided hemiparesis, bilateral gaze direction nystagmus, marked dysarthria with consecutive pervasive mutism, choreo-athetoid movements, spasmodic torticollis and diplopia dependent on gaze direction. Slit lamp examination showed Kayser-Fleischer's corneal ring. EEG- and computer assisted tomography investigations revealed non-specific findings. The patient was treated with D-Penicillamine. Alternative treatment with oral zinc preparations is discussed.

Physical localisation of the chromosomal marker D13S31 places the Wilson disease locus at the junction of bands q14.3 and q21.1 of chromosome 13

D13S31 is the marker closest to the Wilson disease locus according to genetic analysis. Its physical localisation was refined by fluorescent in situ hybridisation to the junction to chromosomal bands 13q14.3 and 13q21.1. Using polymerase chain reaction analysis, D13S31 and D13S59 (the closest proximal and distal marker, respectively) were found to be located on the end of the der(13) consisting of 13pter-13q14.3: in the somatic cell hybrid ICD, and to be absent from the cell lines WC-H38B3B6 containing a del(13) (13pter-q13::13q21.1-qter) and KSF39 containing a del(13) (13pter-q14.1:).

DNA markers for the diagnosis of Wilson disease

Wilson disease is an autosomal recessive disorder of copper transport for which the basic defect is unknown. Laboratory diagnosis of Wilson disease is usually made by measuring serum ceruloplasmin concentration, urinary copper excretion, and liver copper concentration. However, discrimination between heterozygotes and patients is sometimes difficult. The gene for Wilson disease has been assigned to chromosome-13 at q14-q21. In this study, 10 markers from the 13q14-13q21 region were investigated in 12 families with a well-established diagnosis, to confirm reported linkage results. Markers from the same region were tested in two additional families, in which a sib of each index case had unclear results with conventional biochemical assays. The linkage results in this study are similar to those of Middle Eastern families, and support the hypothesis of a single disease locus. In the two families studied for diagnostic purposes, the status of 2 presymptomatic sibs was established as affected and 1 as unaffected. This study therefore shows that DNA markers can be used to discriminate between presymptomatic patients and non-affected individuals when biochemical results are equivocal, as long as an index case with Wilson disease of known status is available and markers are informative.