A novel locus for dHMN with pyramidal features maps to chromosome 4q34.3-q35.2.

The distal hereditary motor neuropathy (dHMN) is a rare genetically and clinically heterogeneous disorder characterized by weakness and wasting of distal limb muscles in absence of overt sensory abnormalities. Recently, pyramidal signs have been also described in some patients with dominant or recessive dHMN, and two different loci have been identified in families affected by dHMN complicated with pyramidal dysfunction. We investigated an Italian family affected by an autosomal dominant dHMN complicated by pyramidal signs in order to map a new gene locus. The disease maps to a novel locus in a 26-cM region flanked by D4S1552 and D4S2930 on chromosome 4q34.3-35.2. Three candidate genes (SNX25, CASP3 and TUBB4Q) located in the critical region were screened for the presence of mutations by heteroduplex analysis. No mutations have been detected in the analyzed genes. In conclusion, the new private genetic locus we reported further confirms the wide heterogeneity of dHMN.

Non-convulsive status epilepticus during lithium treatment at therapeutic doses.

The purpose of this study is to report the case of a patient with normal lithium serum levels who developed non-convulsive status epilepticus (NCSE). A 52-year-old woman with bipolar disorder type I (DSM-IV) treated with lithium experienced bradypsychism and episodes of confusion and spatial disorientation without signs or symptoms of lithium intoxication. Lithium serum levels were in the normal range. A brain MR scan was negative; the electroencephalogram (EEG) revealed a background 3-4 Hz delta rhythm and diffuse spike discharges. Prompt EEG and clinical response to intravenous diazepam therapy was observed. Based on these findings, a diagnosis of NCSE was made and lithium therapy was withdrawn, resulting in symptom remission and EEG normalization. The treatment was resumed after two months to test the correlation between NCSE and lithium therapy. Resumption of therapeutic range lithium induced the same clinical symptoms and EEG patterns; the therapy was thus definitively discontinued. The present data-signalling the temporal correlation of clinical and EEG changes with drug administration and withdrawal-suggest that even in the therapeutic range lithium treatment may trigger NCSE onset in predisposed subjects.