Evidence for susceptibility genes to familial Wilms tumour in addition to WT1, FWT1 and FWT2

Three loci have been implicated in familial Wilms tumour: WT1 located on chromosome 11p13, FWT1 on 17q12-q21, and FWT2 on 19q13. Two out of 19 Wilms tumour families evaluated showed strong evidence against linkage at all three loci. Both of these families contained at least three cases of Wilms tumour indicating that they were highly likely to be due to genetic susceptibility and therefore that one or more additional familial Wilms tumour susceptibility genes remain to be found.

Spinobulbar muscular atrophy: polyglutamine-expanded androgen receptor is proteolytically resistant in vitro and processed abnormally in transfected cells

The neuronotoxicity of genes with expanded CAG repeats is most likely mediated by their respective polyglutamine (Gln)-expanded gene products. Gln- expanded portions of these products may be sufficient, or necessary, for pathogenesis. We tested whether a Gln-expanded human androgen receptor (AR) is structurally altered, so that it allows for the proteolytic generation of a potentially pathogenic portion that may be resistant to further degradation. We found, in vitro , that a Gln-expanded AR is more proteolytically resistant than normal, and that it yields a distinct set of Gln-expanded fragments even after extended proteolysis in the presence of 2 M urea. Furthermore, COS cells transfected with CAG-expanded AR cDNA generate an aberrant, nuclear-associated 75 kDa derivative containing the Gln-expanded tract. They are also twice as likely to die by 24 h apoptotically than those transfected with normal AR cDNA. Our data support the notion that an unconventional derivative of the Gln- expanded AR is a component of the proximate motor neuronopathic agent in spinobulbar muscular atrophy. They also focus attention on two ways in which neuronotoxic derivatives may originate from various Gln-expanded proteins: (i) generation of an unusual derivative that is pathogenic de novo ; and (ii) the toxic accumulation of a normal derivative because of an inability to dispose of it.