MPZL2-a common autosomal recessive deafness gene related to moderate sensorineural hearing loss in the Chinese population.

BACKGROUND: Mutations in MPZL2, the characteristic genetic etiology of autosomal recessive deafness loci 111 (DFNB111), cause non-syndromic and moderate sensorineural hearing loss. METHODS: In this study, we analyzed the phenotype and genotype of eight pedigrees consisting of 10 hearing loss patients with bi-allelic pathogenic or likely pathogenic variants in MPZL2. These patients were identified from a 3272 Chinese patient cohort who underwent genetic testing. RESULTS: Apart from symmetrical and moderate sensorineural hearing loss, the MPZL2-related phenotype was characterized by progressive hearing loss with variation in the onset age (congenital defect to onset at the young adult stage). We determined that in the Chinese population, the genetic load of MPZL2 defects was 0.24% (8/3272) in patients diagnosed with hearing loss and 7.02% (8/114) in patients diagnosed with hereditary moderate sensorineural hearing loss caused by STRC, OTOA, OTOG, OTOGL, TECTA, MPZL2 and others. Three known MPZL2 variants (c.220C > T (p.Gln74*), c.68delC (p.Pro23Leufs*2), c.463delG (p.Ala155Leufs*10)) and a novel start loss variant (c.3G > T (p.Met1?)) were identified. MPZL2 c.220C > T was identified as the hotspot variant in the Chinese population and even in East Asia compared with c.72delA (p.Ile24Metfs*22) in European and West Asia through allele frequency. CONCLUSIONS: We concluded that apart from moderate HL, progressive HL is another character of MPZL2-related HL. No specified variant was verified for the progression of HL, the penetrance and expressivity cannot be determined yet. A novel MPZL2 variant at the start codon was identified, enriching the variant spectrum of MPZL2. The hotspot variants of MPZL2 vary in different ethnicities. This study provides valuable data for the diagnosis, prognosis evaluation and genetic counseling of patients with moderate sensorineural hearing loss related to MPZL2.

[Speciation analysis of cadmium in cadmium-enriched plants with SE-HPLC combined with ICP-MS and ESI-MS].

Different species of ferns (pyrrosia lingua, Lepisorus thunbergianus, Lycopodium japonicum, Elaphoglossum yoshinagae and Woodwardia japonica) were cultivated using different species of cadmium as cultivation solution. The results showed that there were differences in enrichment amounts of cadmium in different parts of plants (amounts in root > in stem > in leaves). And it was found that different species of cadmium could induce synthesization of plant--chelated peptides (PCs) with different extents. And then PCs was coordinated with cadmium to decrease the toxicity from cadmium. There are some kinds of peptides ligands found in plants, which are mainly PC3, iso-PC3(betaAla) and iso-PC2(betaAla). In the present paper, the distribution of cadmium in different parts of ferns was studied after the ferns were intimidated with different species of cadmium. And the species of PCs-Cd coordination compounds were also investigated to explain the detoxification mechanism aroused by it.

[New approaches to selenium speciation].

A review of the recent developments in selenium speciation analysis was presented, focusing on the techniques of separation, interface, elemental specific detection and identification of selenium species; the methods of sample storage and pretreatment storage for selenium speciation were also introduced.

[Digital signal acquisition and processing software for atomic fluorescence spectrometry and its application to elemental speciation].

A program was developed to collect and process digital signal by using Visual C++ for atomic fluorescence spectrometry (AFS). The software solves the data acquisition problem of coupling AFS with HPLC and other successive separation techniques. This program employs three signal processing techniques, i.e. Savitzky-Golay smoothing, Fourier filter and wavelet denoising, to smooth and filter the noisy data. The processes and comparisons of these techniques have been discussed. The program was successfully applied to the preliminary study of Cd speciation by using cation exchange HPLC coupled to AFS, and will provide a new possibility for extending the application of atomic fluorescence spectrometry to the field of elemental speciation analysis.