The pb-zn (Ba) nonsulfide mineralizations at bou caïd (ouarsenis, algeria): Mineralogy, isotope geochemistry, and genetic inferences

The ore deposits of Bou Caïd (Ouarsenis, Algeria) occur in Jurassic and Cretaceous sedimentary rocks. The barite and Pb-Zn (Fe, Cu, and F) ore deposits of Bou Caïd belong to vein-and karst-type. The mineralization is represented in the whole area by a mixture of barite (currently still exploited) and nonsulfides consisting of hemimorphite, smithsonite, cerussite, hydrozincite, and Feoxy-hydroxides, with remnants of galena and sphalerite in variable proportions. Mineralogical and geochemical analyses were carried out on the Bou Caïd nonsulfides. Several samples representing nonsulfide mineralization (Grand Pic and at Srâa Abdelkader) were subjected to a multidisciplinary analytical approach, using optical microscopy (OM), powder X-ray diffraction (PXRD), Scanning Electron Microscopy with Energy Dispersive Spectrometry (SEM-EDS). Nonsulfide mineralization consists of a mixture of hemimorphite, hydrozincite, smithsonite, cerussite, and Fe-oxy-hydroxides, often with zebra-like textures. In the proposed paragenetic scheme, covellite and chalcocite are followed by cerussite, jarosite, smithsonite, and hydrozincite. Then, hemimorphite crystallizes, accompanied by mimetite, traces of malachite and clay minerals (also Zn-bearing), precipitate. Fe(Mn)-oxy-hydroxides can form during various phases of the supergene stage. Small amounts of late barite can be related to partial remobilization and occur as reprecipitation products. Stable isotope analyses were performed on the calcites and metal carbonates of the supergene ores. Carbon and oxygen isotope values of smithsonite and hydrozincite were comparable to published supergene Zn carbonate data. The isotope values of the Bou Caïd calcites fell both into the hydrothermal carbonate and in the supergene fields

Adult cases of mitochondrial DNA depletion due to TK2 defect: an expanding spectrum

In this study we aim to demonstrate the occurrence of adult forms of TK2 mutations causing progressive mitochondrial myopathy with significant muscle mitochondrial DNA (mtDNA) depletion.status: publishe

A novel biallelic splice site mutation of TECTA causes moderate to severe hearing impairment in an Algerian family

International audienceCongenital deafness is certainly one of the most common monogenic diseases in humans, but it is also one of the most genetically heterogeneous, which makes molecular diagnosis challenging in most cases. Whole-exome sequencing in two out of three Algerian siblings affected by recessively-inherited, moderate to severe sensorineural deafness allowed us to identify a novel splice donor site mutation (c.5272+1G>A) in the gene encoding α-tectorin, a major component of the cochlear tectorial membrane. The mutation was present at the homozygous state in the three affected siblings, and at the heterozygous state in their unaffected, consanguineous parents. To our knowledge, this is the first reported TECTA mutation leading to the DFNB21 form of hearing impairment among Maghrebian individuals suffering from congenital hearing impairment, which further illustrates the diversity of the genes involved in congenital deafness in the Maghreb

Diversity of the causal genes in hearing impaired Algerian individuals identified by whole exome sequencing

The genetic heterogeneity of congenital hearing disorders makes molecular diagnosis expensive and time-consuming using conventional techniques such as Sanger sequencing of DNA. In order to design an appropriate strategy of molecular diagnosis in the Algerian population, we explored the diversity of the involved mutations by studying 65 families affected by autosomal recessive forms of nonsyndromic hearing impairment (DFNB forms), which are the most prevalent early onset forms. We first carried out a systematic screening for mutations in GJB2 and the recurrent p.(Arg34*) mutation in TMC1, which were found in 31 (47.7%) families and 1 (1.5%) family, respectively. We then performed whole exome sequencing in nine of the remaining families, and identified the causative mutations in all the patients analyzed, either in the homozygous state (eight families) or in the compound heterozygous state (one family): (c.709C>T: p.(Arg237*)) and (c.2122C>T: p.(Arg708*)) in OTOF, (c.1334T>G: p.(Leu445Trp)) in SLC26A4, (c.764T>A: p.(Met255Lys)) in GIPC3, (c.518T>A: p.(Cys173Ser)) in LHFPL5, (c.5336T>C: p.(Leu1779Pro)) in MYO15A, (c.1807G>T: p.(Val603Phe)) in OTOA, (c.6080dup: p.(Asn2027Lys*9)) in PTPRQ, and (c.6017del: p.(Gly2006Alafs*13); c.7188_7189ins14: p.(Val2397Leufs*2)) in GPR98. Notably, 7 of these 10 mutations affecting 8 different genes had not been reported previously. These results highlight for the first time the genetic heterogeneity of the early onset forms of nonsyndromic deafness in Algerian families