We performed a multicenter prevalence study of nontuberculous mycobacteria (NTM) involving 1,582 patients (mean age, 18.9 years; male/female ratio, 1.06) with cystic fibrosis in France. The overall NTM prevalence (percentage of patients with at least one positive culture) was 6.6% (104/1,582 patients), with prevalences ranging from 3.7% (in the east of France) to 9.6% (in the greater Paris area). Mycobacterium abscessus complex (MABSC; 50 patients) and Mycobacterium avium complex (MAC; 23 patients) species were the most common NTM, and the only ones associated with fulfillment of the American Thoracic Society bacteriological criteria for NTM lung disease. The "new" species, Mycobacterium bolletii and Mycobacterium massiliense, accounted for 40% of MABSC isolates. MABSC species were isolated at all ages, with a prevalence peak between 11 and 15 years of age (5.8%), while MAC species reached their highest prevalence value among patients over 25 years of age (2.2%).Nontuberculous mycobacteria (NTM) have emerged as "new" pathogens in cystic fibrosis (CF) patients over the last 2 decades (10). CF centers worldwide have reported isolation of NTM from the respiratory tracts of CF patients, with prevalence values ranging from 5% to 20% (5,6,8,9,13,14,16,19,22,25). Mycobacterium avium complex (MAC) and Mycobacterium abscessus complex (MABSC) species are the most frequently isolated NTM and together account for Ͼ95% of NTM lung diseases affecting CF patients. The MAC, a member of the subgroup comprising slowly growing mycobacteria, ranks first in North America (22), whereas the MABSC, a member of the subgroup comprising rapidly growing mycobacteria, seems to predominate in Western Europe (15,23,25) and is also more prevalent than the MAC in Israel (19).Previous studies have reported isolation of NTM from 6.6 to 9.8% of French CF cohorts (9,23,25). These studies also reported a much higher isolation rate for MABSC than for MAC or other NTM species (23,25). However, these studies were done exclusively in pediatric CF centers in Paris. This may have distorted the results since MABSC species are more prevalent than MAC species in children (23). Moreover, the epidemiology of NTM in Paris does not necessarily reflect the situation in other regions of France. For example, studies involving non-CF patients have reported higher rates of NTM disease in urban areas (20). Moreover, previous French studies were performed before M. abscessus (now M. abscessus sensu lato, or the MABSC) was shown to include at least three distinct species, M. abscessus (sensu stricto) (hereafter referred to as M. abscessus), Mycobacterium massiliense, and Mycobacterium bolletii (1,3). The prevalences of these three species in CF patients in France were therefore unknown.We thus conducted a large, prospective, nationwide study addressing NTM prevalence in CF patients in France. This study shows relatively low prevalence figures for French CF centers. It also provides evidence that MABSC species are currently the most prevalent NTM in the French CF populat...
Bantu languages are spoken by about 310 million Africans, yet the genetic history of Bantu-speaking populations remains largely unexplored. We generated genomic data for 1318 individuals from 35 populations in western central Africa, where Bantu languages originated. We found that early Bantu speakers first moved southward, through the equatorial rainforest, before spreading toward eastern and southern Africa. We also found that genetic adaptation of Bantu speakers was facilitated by admixture with local populations, particularly for the and loci. Finally, we identified a major contribution of western central African Bantu speakers to the ancestry of African Americans, whose genomes present no strong signals of natural selection. Together, these results highlight the contribution of Bantu-speaking peoples to the complex genetic history of Africans and African Americans.
We analyzed 12 families with autosomal dominant early-onset Alzheimer' s disease (EOAD)for mutations in the coding region of the presenilin I (PSNLI) gene corresponding to the AD3 locus on chromosome 14q24.3. A total of eight missense mutations at codons 82, 115, 139, 163, 231, 264, 392, and 410 including six novel mutations, were identified in eight families. Cosegregation of the mutations with EOAD was confirmed in three families, one including 36 affected individuals. This study underlines the great allelic heterogeneity and the large distribution of the mutations within the PSNLI coding region. Our results support the notion that PSNLI is the major gene involved in autosomal dominant EOAD.
Background: Cystic fibrosis (CF) is caused by compound heterozygosity or homozygosity of CF transmembrane conductance regulator gene (CFTR) mutations. Phenotypic variability associated with certain mutations makes genetic counselling difficult, notably for R117H, whose disease phenotype varies from asymptomatic to classical CF. The high frequency of R117H observed in CF newborn screening has also introduced diagnostic dilemmas. The aim of this study was to evaluate the disease penetrance for R117H in order to improve clinical practice. Methods: The phenotypes in all individuals identified in France as compound heterozygous for R117H and F508del, the most frequent CF mutation, were described. F508del] was estimated at 0.03% and that of severe CF in adulthood at 0.06%. Conclusions: These results suggest that R117H should be withdrawn from CF mutation panels used for screening programmes. The real impact of so-called disease mutations should be assessed before including them in newborn or preconceptional carrier screening programmes.Cystic fibrosis (CF, MIM 219700) is one of the most frequent life shortening autosomal recessive diseases, characterised in its classical form by chronic pulmonary obstruction and infections, pancreatic insufficiency, male infertility and elevated sweat chloride concentrations.
MAC affects adult patients with a mild form of CF, whereas MABSC affects younger patients with more severe CF and more frequent intravenous antimicrobial treatment.
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