Hemophagocytic lymphohistiocytosis associated with brucellosis.

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening immune disorder categorized as familial HLH or secondary HLH. Our case report describes a 63-year-old woman with epilepsy whose clinical signs were unremitting fever and altered consciousness. Primary abnormalities consisted of fever, splenomegaly, cytopenia, hypertriglyceridemia, hyperferritinemia and hemophagocytosis in the bone marrow. Results of blood next generation sequencing and blood culture confirmed Brucella infection. This report illustrates a sHLH case caused by Brucella melitensis infection. Here, we review the classification, clinical features, diagnostic methods, treatment regimens, differential diagnosis, and prognosis of HLH and brucellosis.

A Simple and Highly Sensitive Naked-Eye Analysis of EGFR 19del via CRISPR/Cas12a Triggered No-Nonspecific Nucleic Acid Amplification.

The mutation status of epidermal growth factor receptor (EGFR) exon 19 is of great importance for predicting sensitivity to tyrosine kinase inhibitors (TKIs) in the treatment of non-small-cell lung cancer (NSCLC). However, the development of simple, sensitive, and no-nonspecific amplification platforms for EGFR 19del detection in NSCLC remains a challenge. Herein, we developed a novel, simple, and highly sensitive naked-eye assay utilizing CRISPR/Cas12a-triggered no-nonspecific nucleic acid amplification (NAA) with rolling circle amplification (RCA) as a model for EGFR 19del detection. Typically, circular padlocks are designed to be the trans-cleavage substrate of Cas12a/crRNA and serve as templates for RCA. Since the target EGFR 19del induces robust trans-cleavage activity of the Cas12a/crRNA duplex, the surrounding circular padlocks are cleaved into random short linear fragments that are unable to initiate RCA, resulting in a colorless solution. However, in the absence of EGFR 19del, the inactivated Cas12a enzymes cannot cleave the circular padlocks, and they remain able to serve as templates to initiate RCA to generate long single-stranded DNA to further fold into G-quadruplex/hemin DNAzymes to catalyze the oxidation of 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS2-), generating a color response that is obvious to the naked eye. As expected, this strategy with a detection limit as low as 20 fM exhibited robust selectivity and anti-interference ability. Moreover, this method was applicable for detecting EGFR 19del in real serum samples and showed high consistency with real-time quantitative polymerase chain reaction (qPCR) and sequencing results, providing a promising strategy for the early noninvasive diagnosis and guidance of clinical treatment for cancer.

Rapid Detection of Clostridium tetani by Recombinase Polymerase Amplification Using an Exo Probe.

Tetanus is a potentially fatal public health illness resulted from the neurotoxins generated by Clostridium tetani. C. tetani is not easily culturable and culturing the relevant bacteria from infected wounds has rarely been useful in diagnosis; PCR-based assays can only be conducted at highly sophisticated laboratories. Therefore, a real-time recombinase polymerase amplification assay (Exo-RPA) was constructed to identify the fragments of the neurotoxin gene of C. tetani. Primers and the exo probe targeting the conserved region were designed, and the resulting amplicons could be detected in less than 20 min, with a detection limit of 20 copies/reaction. The RPA assay displayed good selectivity, and there were no cross-reactions with other infectious bacteria common in penetrating wounds. Tests of target-spiked serum and pus extract revealed that RPA is robust to interfering factors and has great potential for further development for biological sample analysis. This method has been confirmed to be reliable for discriminating between toxic and nontoxic C. tetani strains. The RPA assay dramatically improves the diagnostic efficacy with simplified device architecture and is a promising alternative to real-time PCR for tetanus detection.

Rare partial trisomy and tetrasomy of 15q11-q13 associated with developmental delay and autism spectrum disorder.

BACKGROUND: Small supernumerary marker chromosomes (sSMCs), are additional abnormal chromosomes, which can't be detected accurately by banding cytogenetic analysis. Abnormal phenotypes were observed in about 30% of SMC carriers. Duplication of chromosome 15 and related disorders, characterized by hypotonia motor delays, autism spectrum disorder (ASD), intellectual disability, and epilepsy including infantile spasms, might be account for 50% of the total sSMCs. CASE PRESENTATION: An 11-month-old infant with an sSMC found by banding cytogenetics was referred to our clinic because of developmental retardation and autism spectrum disorder. After several months of rehabilitation treatment, the progress of motor development was obvious, but the consciousness was still far from satisfied. High-resolution karyotype analysis, multiplex ligation-dependent probe amplification and copy number variation sequencing (CNV-Seq) were conducted to confirm the identity of the sSMC. A bisatellited dicentric sSMC was observed clearly in high-resolution karyotype analysis and a 10.16-Mb duplication of 15q11.1q13.2 (3.96 copies) together with a 1.84-Mb duplication of 15q13.2q13.3 (3 copies) was showed by CNV-Seq in the proband. It suggested that the molecular cytogenetic karyotype was 47,XY,+dic(15;15)(q13.2;q13.3). Furthermore, the clinical symptoms of the proband mostly fit 15q duplication related disorders which are characterized by hypotonia motor delays, autism spectrum disorder (ASD), and intellectual disability. CONCLUSION: We reported for the first time using CNV-Seq to detect sSMCs and find a partial trisomy and tetrasomy of 15q11-q13 associated with developmental delay and autism spectrum disorder. Our report indicates that CNV-seq is a useful and economical way for diagnosis of dup15q and related disorders.

Molecular characterization of α- and ß-thalassemia in the Yulin region of Southern China.

Thalassemia is one of the most common hereditary blood disorders. Epidemiological data regarding the prevalence and distribution of mutations is important for planning a thalassemia control program. To reveal the prevalence of thalassemia and mutation spectrum in the Yulin region of southern China, we screened 130,318 individuals from Yulin region by hematological and genetic analysis. Totally, 24,886 (19.10%) subjects were diagnosed with thalassemia, including 16,308 (12.51%) subjects with α-thalassemia alone, 6658 (5.11%) subjects with ß-thalassemia alone and 1920 (1.47%) subjects with both α- and ß-thalassemia. Ten α-thalassemia mutations were identified in the α-thalassemia subjects, with the common α-thalassemia mutations being --SEA mutation (51.91%), -α3.7 (19.90%), αCSα (10.58%), -α4.2 (8.13%), αWSα (7.67%). Thirteen ß-thalassemia mutations and 31 genotypes were characterized in the ß-thalassemia subjects. The seven common mutations [CD41-42 (-CTTT) (43.31%), CD17 (A > T) (34.58%), CD26 (G > A) (6.86%), CD71-72 (+A) (4.25%), -28 (A > G) (3.90%), IVS-II-654 (C > T) (3.53%) and IVS-I-1 (G > T) (2.22%)] accounted for 98.65% of all ß-thalassemia defects. Furthermore, 6 cases of α-triplication and 3 cases of mutation -α2.4 were first identified in this region. Our data illustrated that there was great heterogeneity and extensive spectrum of thalassemias in the Yulin populations. The findings will contribute an available reference for prevention of thalassemia in this region.