Early T-Cell Precursor Acute Lymphoblastic Leukemia in an Infant With an NRAS Q61R Mutation and Clinical Features of Juvenile Myelomonocytic Leukemia.

Early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) is a subtype of T-acute lymphoblastic leukemia (T-ALL) arising from a primitive precursor. We present a unique case of an infant with ETP-ALL with a missense NRAS mutation in codon 61 (c.182A>G, p.Q61R). The patient also had a minor population of non-ETP T-ALL blasts and clinical features typically associated with juvenile myelomonocytic leukemia (JMML), namely, absolute monocytosis, splenomegaly, and elevated hemoglobin F. The treatment was initiated with chemotherapy, followed by cord blood transplantation. The patient achieved remission, but unfortunately died from transplant-related complications. This case highlights an NRAS mutation in ETP-ALL with JMML-like phenotype.

Molecular profiling of soft tissue sarcomas using next-generation sequencing: a pilot study toward precision therapeutics.

Next-generation sequencing (NGS) can provide in-depth detection of numerous gene alterations. To date, there are very few reports describing the use of this technique in soft tissue sarcomas. Herein, we aim to test the utility of NGS in identifying targetable mutations in these tumors. NGS was performed using a clinically validated multiplexed gene sequencing panel interrogating the full coding sequence of 194 cancer-related genes. A custom bioinformatics pipeline was developed to detect all classes of mutations directly from the NGS data, including single-nucleotide variants, small insertions and deletions, copy number variation, and complex structural variations. Twenty-five soft tissue sarcomas were analyzed; 18 of these patients had metastatic disease and 7 primary locally advanced tumors. Targetable mutations for which clinical trials are available were identified in 60% of the cases. MAP2K4, AURKA, AURKB, and c-MYC amplification were recurrent events in leiomyosarcomas. Frequent non-targetable variants included copy losses of the TP53 (24%), PTEN (16%), and CDKN2A (20%). Additional frameshift mutations, deletion mutations, and single-nucleotide variants involving numerous genes, including RB1, NOTCH1, PIK3CA, PDGFRB, EPHA5, KDM6A, NF1, and FLT4 genes, were also identified. NGS is useful in identifying targetable mutations in soft tissue sarcomas that can serve as a rationale for inclusion of patients with advanced disease in ongoing clinical trials and allow for better risk stratification.

Digenic inheritance of deafness caused by 8J allele of myosin-VIIA and mutations in other Usher I genes.

Inherited hearing loss in mice has contributed substantially to our understanding of inner-ear function. We identified a new allele at the Myo7a locus, Myo7a(sh1-8J); genomic characterization indicated that Myo7a(sh1-8J) arose from complex deletion encompassing exons 38-40 and 42-46. Homozygous mutant mice had no detectable auditory brainstem response, displayed highly disorganized hair-cell stereocilia and had no detectable MYO7A protein. We generated mice that were digenic heterozygotes for Myo7a(sh1-8J) and one of each Cdh23(v-2J), Ush1g(js) or Pcdh15(av-3J) alleles, or an Ush1c null allele. Significant levels of age-related hearing loss were detected in +/Myo7a(sh1-8J) +/Ush1g(js), +/Myo7a(sh1-8J) +/Cdh23(v-2J) and +/Myo7a(sh1-8J) +/Pcdh15(av-3J) double heterozygous mice compared with age-matched single heterozygous animals, suggesting epistasis between Myo7a and each of the three loci. +/Pcdh15(av-3J) +/Ush1g(js) double heterozygous mice also showed elevated hearing loss, suggesting Pcdh15-Ush1g epistasis. While we readily detected MYO7A, USH1C, CDH23 and PCDH15 using mass spectrometry of purified chick utricle hair bundles, we did not detect USH1G. Consistent with that observation, Ush1g microarray signals were much lower in chick cochlea than those of Myo7a, Ush1c, Cdh23 and Pcdh15 and were not detected in the chick utricle. These experiments confirm the importance of MYO7A for the development and maintenance of bundle function and support the suggestion that MYO7A, USH1G (Sans) and CDH23 form the upper tip-link complex in adult mice, likely in combination with USH1C (harmonin). MYO7A, USH1G and PCDH15 may form another complex in stereocilia. USH1G may be a limiting factor in both complexes.

Uveitis in patients with autoimmune hepatitis.

PURPOSE: To report seven cases of uveitis occurring in patients with autoimmune hepatitis (AIH), raising the possibility that uveitis may be an extrahepatic feature of AIH. DESIGN: Multicenter, retrospective, observational case series of patients with AIH and uveitis. METHODS: One index case was identified at Oregon Health & Science University. Further cases were identified by a web-based survey of members of the American Uveitis Society, the International Uveitis Study Group, the Proctor Foundation mailing list server, and the First SUN International Workshop. Respondents were asked to provide clinical information about uveitis phenotype, AIH features, and treatment. RESULTS: Clinical information was obtained for seven individuals (four females and three males; age range, seven to 67 years) who suffered from AIH and uveitis. Average duration of follow-up was 5.5 years. All patients had chronic, persistent bilateral uveitis that was anterior (n = 3), intermediate (n = 1), or pan (n = 3) in location. Every patient had complications arising from his or her uveitis, including cataract (n = 5), glaucoma (n = 3), cystoid macular edema (n = 3), and posterior synechiae (n = 3). Final visual acuities ranged from 20/16 to hand movements. To treat the uveitis and/or AIH, the majority of patients required oral prednisone and all seven patients were treated with systemic immunosuppression. CONCLUSION: Despite the small size of this study, our findings suggest an association between AIH and uveitis. The uveitis is chronic, bilateral, and associated with sight-threatening complications, necessitating systemic immunosuppression in some individuals.

Fast adaptation in vestibular hair cells requires myosin-1c activity.

In sensory hair cells of the inner ear, mechanical amplification of small stimuli requires fast adaptation, the rapid closing of mechanically activated transduction channels. In frog and mouse vestibular hair cells, we found that the rate of fast adaptation depends on both channel opening and stimulus size and that it is modeled well as a release of a mechanical element in series with the transduction apparatus. To determine whether myosin-1c molecules of the adaptation motor are responsible for the release, we introduced the Y61G mutation into the Myo1c locus and generated mice homozygous for this sensitized allele. Measuring transduction and adaptation in the presence of NMB-ADP, an allele-specific inhibitor, we found that the inhibitor not only blocked slow adaptation, as demonstrated previously in transgenic mice, but also inhibited fast adaptation. These results suggest that mechanical activity of myosin-1c is required for fast adaptation in vestibular hair cells.

Progress toward a human CD4/CCR5 transgenic rat model for de novo infection by human immunodeficiency virus type 1.

The development of a permissive small animal model for the study of human immunodeficiency virus type (HIV)-1 pathogenesis and the testing of antiviral strategies has been hampered by the inability of HIV-1 to infect primary rodent cells productively. In this study, we explored transgenic rats expressing the HIV-1 receptor complex as a susceptible host. Rats transgenic for human CD4 (hCD4) and the human chemokine receptor CCR5 (hCCR5) were generated that express the transgenes in CD4(+) T lymphocytes, macrophages, and microglia. In ex vivo cultures, CD4(+) T lymphocytes, macrophages, and microglia from hCD4/hCCR5 transgenic rats were highly susceptible to infection by HIV-1 R5 viruses leading to expression of abundant levels of early HIV-1 gene products comparable to those found in human reference cultures. Primary rat macrophages and microglia, but not lymphocytes, from double-transgenic rats could be productively infected by various recombinant and primary R5 strains of HIV-1. Moreover, after systemic challenge with HIV-1, lymphatic organs from hCD4/hCCR5 transgenic rats contained episomal 2-long terminal repeat (LTR) circles, integrated provirus, and early viral gene products, demonstrating susceptibility to HIV-1 in vivo. Transgenic rats also displayed a low-level plasma viremia early in infection. Thus, transgenic rats expressing the appropriate human receptor complex are promising candidates for a small animal model of HIV-1 infection.