Accuracy and Performance Evaluation of Triplet Repeat Primed PCR as an Alternative to Conventional Diagnostic Methods for Fragile X Syndrome

Background@#Conventional diagnosis of fragile X syndrome (FXS) is based on a combination of fragment analysis (FA) and Southern blotting (SB); however, this diagnostic approach is time- and labor-intensive and has pitfalls such as the possibility of missing large number alleles. Triplet repeat primed PCR (TP-PCR) is a current alternative used to overcome these limitations. We evaluated the diagnostic usefulness of TP-PCR compared with the conventional diagnostic protocol consisting of FA and/or SB in terms of allele categorization, repeat number correlation, and zygosity concordance in female genetic carriers. @*Methods@#From November 2013 to March 2018, 458 patients (326 males, 132 females) were simultaneously examined using FA and/or SB and TP-PCR by detecting CGG repeat numbers in FMR gene and diagnosed as per American College of Medical Genetics guidelines. @*Results@#The TP-PCR results showed high concordance with the FA and/or SB results for all three aspects (allele categorization, repeat number correlation, and zygosity concordance in female genetic carriers). TP-PCR detected CGG expansions ≥ 200 in all full mutation (FM) allele cases in male patients, as well as both the normal allele (NL) and FM allele in female carriers. In premutation (PM) allele carriers, the TP-PCR results were consistent with the FA and/or SB results. In terms of zygosity concordance in female genetic carriers, 12 NL cases detected by TP-PCR showed a merged peak consisting of two close heterozygous peaks; however, this issue was resolved using a 10-fold dilution. @*Conclusions@#TP-PCR may serve as a reliable alternative method for FXS diagnosis.

Five Cases of the Gram Variable Bacterium Paenibacillus urinalis Isolated from Clinical Specimens and its Clinical Significance

Paenibacillus urinalis was first isolated from the urine of a woman in 2008, and was reported to be a contaminant. Here, we report 5 cases of P. urinalis isolated over 5 months at a tertiary hospital. Using an API kit, 4 cases were classified as Cellulomonas species. Owing to the low reliability of API kit results and Gram stain results indicating gram variable bacilli for few specimens, MALDI-TOF MS and 16S rRNA gene sequencing were performed for identification. The last case showed Gram variable bacilli, and therefore, based on previous experience, 16S rRNA gene base sequence analysis was carried out without an additional API kit. All isolated strains were confirmed to be P. urinalis, and were judged to be contaminants. As for Gram variable bacteria, the use of current biochemical identification systems may lead to misidentification as other bacteria, which may cause unnecessary or improper use of antibiotics. Moreover, whereas most of the Paenibacillus species are reported to be contaminants, some of them are being reported as sources of infection. Therefore, more accurate identification will be necessary in the future. Accordingly, it is expected that accurate identification of this genus will help clinical physicians make decisions regarding appropriate treatment and use of antibiotics.

Therapy-related acute promyelocytic leukemia in plasma cell myeloma treated with melphalan: a case report and literature review

No abstract available.