Exclusion of p75NGFR and other candidate genes in a family with hereditary sensory neuropathy type II.

Hereditary sensory neuropathy Type II (HSN II) is an autosomal recessive disorder characterized by the loss of peripheral sensory modalities in individuals with otherwise normal development. Patients with HSN II often have chronic ulceration of the fingers and toes, autoamputation of the distal phalanges, and neuropathic joint degeneration associated with loss of pain sensation. Recent descriptions of a similar phenotype in mice carrying a targeted mutation in the low affinity nerve growth factor receptor, p75NGFR, suggested the possibility that mutations in this gene or other members of the nerve growth factor (NGF) family of genes and their receptors might be responsible for this human disorder. In this study candidate genes were evaluated by their inheritance pattern in two sisters affected with HSN II, their unaffected sister and mother in a consanguineous family. The segregation of polymorphic alleles at and around loci for p75NGFR, TRKA, TRKB, BDNF, and familial dysautonomia (another hereditary sensory neuropathy having features in common with HSN II) virtually excluded these genes as the cause of HSN II in this family. Further evaluation of loci for other neurotrophic factors and their receptors, which will be possible when mapping information on their loci becomes available, may permit the identification of the gene responsible for HSN II.

Molecular cloning and expression of rat torsinA in the normal and genetically dystonic (dt) rat.

Deletions within the TOR1A gene cause early-onset (DYT1) torsion dystonia. We have cloned and sequenced the rat cDNA homologue of TOR1A and found a 91% identity with the human sequence. Northern blot analysis detects a single transcript of approximately 1.5 kb. In situ hybridization reveals a widespread distribution of torsinA mRNA within brain. No mutations were identified in the coding region of the gene in the genetically dystonic (dt) rat.

Development potential of rifalazil and other benzoxazinorifamycins.

Rifalazil and other benzoxazinorifamycins (new chemical entities [NCEs]) are rifamycins that contain a distinct planar benzoxazine ring. Rifalazil has excellent antibacterial activity, high intracellular levels and high tissue penetration, which are attributes that favour its use in treating diseases caused by the obligate intracellular pathogens of the genus Chlamydia. Recent studies have shown that rifalazil has efficacy in the treatment of human sexually transmitted disease caused by Chlamydia trachomatis. The extraordinary potency of rifalazil and other NCEs, such as ABI-0043, extends to the related microorganism, C. pneumoniae, a respiratory pathogen that can disseminate and persist chronically in the vasculature, resulting in increased plaque formation in animal studies. A pivotal clinical trial with rifalazil has been initiated for the treatment of peripheral arterial disease. Other opportunities include gastric ulcer disease caused by Helicobacter pylori and antibiotic-associated colitis caused by infection with Clostridium difficile in the colon. The NCEs could prove to be valuable as follow-on compounds in these indications, as rifampin replacements in antibacterial combination therapy or as stand-alone topical antibacterials (e.g., to treat acne). Neither rifalazil nor NCEs appear to induce the cytochrome P450 3A4, an attribute of rifampin that can result in adverse events due to drug-drug interactions.