Huntington's disease (HD) is a late manifesting neurodegenerative disorder in humans caused by an expansion of a CAG trinucleotide repeat of more than 39 units in a gene of unknown function. Several mouse models have been reported which show rapid progression of a phenotype leading to death within 3-5 months (transgenic models) resembling the rare juvenile course of HD (Westphal variant) or which do not present with any symptoms (knock-in mice). Owing to the small size of the brain, mice are not suitable for repetitive in vivo imaging studies. Also, rapid progression of the disease in the transgenic models limits their usefulness for neurotransplantation. We therefore generated a rat model transgenic of HD, which carries a truncated huntingtin cDNA fragment with 51 CAG repeats under control of the native rat huntingtin promoter. This is the first transgenic rat model of a neurodegenerative disorder of the brain. These rats exhibit adult-onset neurological phenotypes with reduced anxiety, cognitive impairments, and slowly progressive motor dysfunction as well as typical histopathological alterations in the form of neuronal nuclear inclusions in the brain. As in HD patients, in vivo imaging demonstrates striatal shrinkage in magnetic resonance images and a reduced brain glucose metabolism in high-resolution fluor-deoxy-glucose positron emission tomography studies. This model allows longitudinal in vivo imaging studies and is therefore ideally suited for the evaluation of novel therapeutic approaches such as neurotransplantation.

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A 50 year old woman underwent laparoscopic supracervical hysterectomy because of symptomatic fibroids. Histologic examination of samples obtained after morcellation revealed typical uterine leiomyomas in all samples investigated. 28 and 47 months later, respectively, the patient presented with peritoneal spreading of nodules that were surgically removed and histologically classified as leiomyosarcoma. In 3/4 of samples obtained after morcellation copy number/SNP-array hybridization showed complex genomic alterations widely identical to the pattern characterizing the sarcoma. Therefore, we conclude that the leiomyosarcoma had unambiguously developed from one of the leiomyomas as a result of secondary genetic alterations i.e. a rearrangement of ALK and a del(14q). The case is challenging the current risk estimates for spreading of unexpected malignant uterine tumors due to power morcellation and highlights the relevance of certain genetic alterations for rare malignant transformation of uterine benign smooth muscle tumors.

Regional and subtype selective changes of neurotransmitter receptor density in a rat transgenic for the Huntington's disease mutation.

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