The DNA Alkylguanine DNA Alkyltransferase-2 (AGT-2) Of Caenorhabditis Elegans Is Involved In Meiosis And Early Development Under Physiological Conditions.

DNA alkylguanine DNA alkyltransferases (AGTs) are evolutionary conserved proteins that repair alkylation damage in DNA, counteracting the effects of agents inducing such lesions. Over the last years AGTs have raised considerable interest for both the peculiarity of their molecular mechanism and their relevance in cancer biology. AGT knock out mice show increased tumour incidence in response to alkylating agents, and over-expression of the human AGT protein in cancer cells is frequently associated with resistance to alkylating chemotherapy. While all data available point to a function of AGT proteins in the cell response to alkylation lesions, we report for the first time that one of the two AGT paralogs of the model organism C. elegans, called AGT-2, also plays unexpected roles in meiosis and early development under physiological conditions. Our data suggest a role for AGT-2 in conversion of homologous recombination intermediates into post-strand exchange products in meiosis, and show that agt-2 gene down-regulation, or treatment of animals with an AGT inhibitor results in increased number of germ cells that are incompatible with producing viable offspring and are eliminated by apoptosis. These results suggest possible functions for AGTs in cell processes distinct from repair of alkylating damage.

Agrypnia excitata in a patient with progeroid short stature and pigmented Nevi (Mulvihill-Smith syndrome).

We report the video-polysomnographic sleep characteristics of a 25-year-old woman with the Mulvihill-Smith syndrome, a rare clinical condition characterized by progeria-like aspect, peculiar multiple pigmented nevi, low stature, and cognitive impairment. Among the various exams, two overnight video-polysomnographic recordings were carried out; moreover, cerebral MRI and molecular analysis of the prion protein gene (PRNP) were also performed. The video-polysomnographic recordings showed the absence of clear sleep episodes but the presence of periods during which the patient had poor contact with the environment, stereotyped afinalistic movements of the upper limbs and hands, irregular or periodic breathing (with central apnea episodes), heart rate arrhythmia, and rapid eye movements. Cerebral MRI showed only diffuse mild enlargement of the cortical sulci and the molecular genetics analysis of the PRNP was normal. Our clinical and neurophysiological study seems to indicate that a particular condition of severe sleep disruption, similar to some extent to that reported in the fatal familial insomnia and in the Morvan fibrillary chorea, which has been indicated as Agrypnia Excitata in recent literature, might be associated with the Mulvihill-Smith syndrome. The inclusion of a detailed study on the sleep characteristics of eventual additional patients will certainly help our understanding of this rare condition.

Hereditary haemochromatosis is unlikely to cause movement disorders--a critical review.

Hereditary haemochromatosis (HH) is a common autosomal recessive systemic iron overload disorder in which CNS manifestations, particularly movement disorders, have been reported. We report a 63-year-old woman with familial HH with a four-year history of progressive gait disturbance, chorea, and mild cervical and laryngeal dystonia. Her movement disorder was thought to be related to the haemochromatosis. On further investigation, analysis for the Huntington's disease expansion was positive. A review of the seven published cases of movement disorders associated with HH as well as data concerning brain iron deposition in this condition leads us to debate the causal link between movement disorders and HH. We suggest that movement disorders are rare in association with HH, and that such patients should be thoroughly investigated for another cause for their movement disorder.

An unusual family with multiple movement disorders.

Multiple movement disorders presenting in the same family are rare. We present an unusual family where generalized dystonia, Huntington's disease, progressive supranuclear palsy and secondary paroxysmal dyskinesia co-exist. The index case presented with young-onset dystonia and tested negative for the DYT1 gene deletion. Her father was similarly affected. The father's brother (paternal uncle of the index) also had abnormal movements-a mixture of chorea and dystonia-and tested positive for the HD expansion. His son had secondary paroxysmal dyskinesia, and tested negative for the HD expansion. The index case and her father were also negative for the HD expansion. A paternal aunt of two of the cases had a clinical diagnosis of progressive supranuclear palsy. Dystonia is known to be a genetically heterogeneous condition. The co-existence of inherited generalized dystonia with other movement disorders may provide clues to its genetic localization.