An Emerging Female Phenotype with Loss‐of‐Function Mutations in the Aristaless‐Related Homeodomain Transcription Factor ARX

The devastating clinical presentation of X‐linked lissencephaly with abnormal genitalia (XLAG) is invariably caused by loss‐of‐function mutations in the Aristaless‐related homeobox (ARX) gene. Mutations in this X‐chromosome gene contribute to intellectual disability (ID) with co‐morbidities including seizures and movement disorders such as dystonia in affected males. The detection of affected females with mutations in ARX is increasing. We present a family with multiple affected individuals, including two females. Two male siblings presenting with XLAG were deceased prior to full‐term gestation or within the first few weeks of life. Of the two female siblings, one presented with behavioral disturbances, mild ID, a seizure disorder, and complete agenesis of the corpus callosum (ACC), similar to the mother's phenotype. A novel insertion mutation in Exon 2 of ARX was identified, c.982delCinsTTT predicted to cause a frameshift at p.(Q328Ffs^*37). Our finding is consistent with loss‐of‐function mutations in ARX causing XLAG in hemizygous males and extends the findings of ID and seizures in heterozygous females. We review the reported phenotypes of females with mutations in ARX and highlight the importance of screening ARX in male and female patients with ID, seizures, and in particular with complete ACC.     

Acute hearing loss

Opinion statement Acute hearing loss (AHL) is a medical urgency. The management of patients presenting with sudden deafness involves detecting the causal mechanism and administering emergency therapeutic drugs to restore hearing by minimizing the period of cellular ischemia to the inner ear. Acute management of AHL consists of administering a 10-day course of high-dose corticosteroids (prednisone 60 to 80 mg) until a cause can be established. Magnetic resonance imaging with gadolinium is indicated, with a study dedicated to the internal auditory canals. The natural history of idiopathic AHL is characterized by spontaneous improvement in two thirds of patients. Maximum improvement occurs within 2 weeks of onset of AHL. In the vast majority of patients (>90%), the AHL is idiopathic. For an identifiable etiology, the treatment is specific and may consist of stopping ototoxic medications, repair of perilymphatic fistulas, administering antimicrobial agents for viral or bacterial infections, correction of metabolic imbalances, management of stroke, and possible surgery for cerebellopontine angle tumors. Management of idiopathic AHL is controversial. Various therapeutic agents, such as vasodilators, diuretics, anticoagulants, plasma expanders, contrast agents, and carbogen inhalation, have been tried in single therapy or as a combination therapy. The empiric use of these drugs is mainly based on improving the blood circulation and restoring the oxygen tension to the inner ear. The use of interventional procedures, such as low-density lipoprotein apheresis as well as newer drug delivery systems for corticosteroids, and immunosuppressive agents have opened new options in the treatment of AHL secondary to immunemediated diseases of the inner ear. Prognosis for AHL is best when patients are seen early, begin recovery within 2 weeks, and have a mild hearing loss (<90 dB) with upward-sloping audiograms. Greater than 90 dB of hearing loss along with flat or down sloping audiogram, advanced age, and presence of vertigo are adverse prognostic factors for recovery of hearing loss.     

The absence of direct antimicrobial activity in extracts of cytotoxic lymphocytes

An important mechanism used by the immune system in resisting infections by intracellular pathogens is the destruction of host cells by cytolytic lymphocytes. Whether these lymphocytes display a more direct antimicrobial action remains unclear. We have attempted to answer this question by testing extracts of cytolytic lymphocytes, prepared by cell fractionation, against three bacterial species - Escherichia coli, Salmonella typhimurium, and Listeria monocytogenes. We also tested these extracts against two viruses - pseudorabies virus and vesicular stomatitis virus. The extracts showed negligible activity against the test organisms under the conditions used.     

Microsampling: A role to play in Covid-19 diagnosis,surveillance, treatment and clinical trials

The outbreak of the new coronavirus disease changed the world upside down. Every day, millions of people were subjected to diagnostic testing for Covid-19, all over the world. Molecular tests helped in the diagnosis of current infection by detecting the presence of viral genome whereas serological tests helped in detecting the presence of antibody in blood as well as contributed to vaccine development. This testing helped in understanding the immunogenicity, community prevalence, geographical spread and conditions post-infection. However, with the contagious nature of the virus, biological specimen sampling involved the risk of transmission and spread of infection. Clinic or pathology visit was the most concerning part. Trained personnel and resources was another barrier. In this scenario, microsampling played an important role due to its most important advantage of remote, contactless, small volume and self-sampling. Minimum requirements for sample storage and ease of shipment added value in this situation. The highly sensitive instruments and validated assay formats assured the accuracy of results and stability of samples. Microsampling techniques are contributing effectively to the Covid-19 pandemic by reducing the demand for clinical staff in population-level testing. The validated and established applications supported the use of microsampling in diagnosis, therapeutic drug monitoring, development of treatment or vaccines and clinical trials for Covid-19.     

Inhibition of SETMAR–H3K36me2–NHEJ repair axis in residual disease cells prevents glioblastoma recurrence

BackgroundResidual disease of glioblastoma (GBM) causes recurrence. However, targeting residual cells has failed, due to their inaccessibility and our lack of understanding of their survival mechanisms to radiation therapy. Here we deciphered a residual cell–specific survival mechanism essential for GBM relapse.MethodsTherapy resistant residual (RR) cells were captured from primary patient samples and cell line models mimicking clinical scenario of radiation resistance. Molecular signaling of resistance in RR cells was identified using RNA sequencing, genetic and pharmacological perturbations, overexpression systems, and molecular and biochemical assays. Findings were validated in patient samples and an orthotopic mouse model.ResultsRR cells form more aggressive tumors than the parental cells in an orthotopic mouse model. Upon radiation-induced damage, RR cells preferentially activated a nonhomologous end joining (NHEJ) repair pathway, upregulating Ku80 and Artemis while downregulating meiotic recombination 11 (Mre11) at protein but not RNA levels. Mechanistically, RR cells upregulate the Su(var)3-9/enhancer-of-zeste/trithorax (SET) domain and mariner transposase fusion gene (SETMAR), mediating high levels of H3K36me2 and global euchromatization. High H3K36me2 leads to efficiently recruiting NHEJ proteins. Conditional knockdown of SETMAR in RR cells induced irreversible senescence partly mediated by reduced H3K36me2. RR cells expressing mutant H3K36A could not retain Ku80 at double-strand breaks, thus compromising NHEJ repair, leading to apoptosis and abrogation of tumorigenicity in vitro and in vivo. Pharmacological inhibition of the NHEJ pathway phenocopied H3K36 mutation effect, confirming dependency of RR cells on the NHEJ pathway for their survival.ConclusionsWe demonstrate that the SETMAR-NHEJ regulatory axis is essential for the survival of clinically relevant radiation RR cells, abrogation of which prevents recurrence in GBM.     

A quality improvement initiative to increase pneumococcal vaccination coverage among children after kidney transplant

Pneumococcal vaccination rates among children receiving a kidney transplant remain suboptimal. Current practice guidelines in the United States recommend giving the PPSV23 after priming with the PCV13. We conducted a QI initiative to increase pneumococcal vaccine rates in our kidney transplant recipients by developing an age‐based vaccine algorithm, obtaining vaccine records, and generating reminders for patients and clinicians. A monthly report from the EHR tracked outcomes. The process metric was missed vaccine opportunities, and the overall objective was to improve coverage with both the PCV13 and PPSV23. Over the first six months, we increased the percentage of visits where the vaccine was given from a baseline of 4% to 33%. However, by the end of the 12‐month period, the percentage of eligible visits where the vaccine was given decreased to 8.7%. Nevertheless, over the 12‐month observation period, we were able to increase the percentage of transplant patients receiving the PCV13 and PPSV23 from 6% to 52%. Utilizing an age‐based algorithm and the electronic medical record, vaccine champions can track both missed visit opportunities and the number of vaccinated patients to improve pneumococcal immunization coverage for these high‐risk patients.     

Pathogenesis of SIVmac Infection in Chinese and Indian Rhesus Macaques: Effects of Splenectomy on Virus Burden

The spleen and lymph nodes are the predominant sites of viral replication in SIV and HIV infections. We studied splenectomized and control unsplenectomized rhesus macaques of both the Indian and the Chinese subspecies of Macaca mulatta. All animals were inoculated with SIV_mac239, a molecularly cloned strain of SIV. Our data showed: (1) splenectomized animals, particularly among the Indian subspecies, had a lower virus burden and longer survival than unsplenectomized controls, (2) the Chinese macaques controlled virus replication more effectively than did the Indian animals, and (3) that a higher infectious virus burden was present in LN/spleen than in blood in both splenectomized and control animals.