Immune-Deficient Drosophila melanogaster: A Model for the Innate Immune Response to Human Fungal Pathogens

We explored the host-pathogen interactions of the human opportunistic fungus Candida albicans using Drosophila melanogaster. We established that a Drosophila strain devoid of functional Toll receptor is highly susceptible to the human pathogen C. albicans. Using this sensitive strain, we have been able to show that a set of specific C. albicans mutants of different virulence in mammalian infection models are also impaired in virulence in Drosophila and remarkably display the same rank order of virulence. This immunodeficient insect model also revealed virulence properties undetected in an immunocompetent murine model of infection. The genetic systems available in both host and pathogen will enable the identification of host-specific components and C. albicans genes involved in the host-fungal interplay.

Evolutionary history and global spread of the Mycobacterium tuberculosis Beijing lineage.

Mycobacterium tuberculosis strains of the Beijing lineage are globally distributed and are associated with the massive spread of multidrug-resistant (MDR) tuberculosis in Eurasia. Here we reconstructed the biogeographical structure and evolutionary history of this lineage by genetic analysis of 4,987 isolates from 99 countries and whole-genome sequencing of 110 representative isolates. We show that this lineage initially originated in the Far East, from where it radiated worldwide in several waves. We detected successive increases in population size for this pathogen over the last 200 years, practically coinciding with the Industrial Revolution, the First World War and HIV epidemics. Two MDR clones of this lineage started to spread throughout central Asia and Russia concomitantly with the collapse of the public health system in the former Soviet Union. Mutations identified in genes putatively under positive selection and associated with virulence might have favored the expansion of the most successful branches of the lineage.

STXBP1 encephalopathy: A neurodevelopmental disorder including epilepsy

OBJECTIVE To give a comprehensive overview of the phenotypic and genetic spectrum of STXBP1 encephalopathy (STXBP1-E) by systematically reviewing newly diagnosed and previously reported patients. METHODS We recruited newly diagnosed patients with STXBP1 mutations through an international network of clinicians and geneticists. Furthermore, we performed a systematic literature search to review the phenotypes of all previously reported patients. RESULTS We describe the phenotypic features of 147 patients with STXBP1-E including 45 previously unreported patients with 33 novel STXBP1 mutations. All patients have intellectual disability (ID), which is mostly severe to profound (88%). Ninety-five percent of patients have epilepsy. While one-third of patients presented with Ohtahara syndrome (21%) or West syndrome (9.5%), the majority has a nonsyndromic early-onset epilepsy and encephalopathy (53%) with epileptic spasms or tonic seizures as main seizure type. We found no correlation between severity of seizures and severity of ID or between mutation type and seizure characteristics or cognitive outcome. Neurologic comorbidities including autistic features and movement disorders are frequent. We also report 2 previously unreported adult patients with prominent extrapyramidal features. CONCLUSION De novo STXBP1 mutations are among the most frequent causes of epilepsy and encephalopathy. Most patients have severe to profound ID with little correlation among seizure onset, seizure severity, and the degree of ID. Accordingly, we hypothesize that seizure severity and ID present 2 independent dimensions of the STXBP1-E phenotype. STXBP1-E may be conceptualized as a complex neurodevelopmental disorder rather than a primary epileptic encephalopathy.