Variation in a range of mTOR-related genes associates with intracranial volume and intellectual disability.

De novo mutations in specific mTOR pathway genes cause brain overgrowth in the context of intellectual disability (ID). By analyzing 101 mMTOR-related genes in a large ID patient cohort and two independent population cohorts, we show that these genes modulate brain growth in health and disease. We report the mTOR activator gene RHEB as an ID gene that is associated with megalencephaly when mutated. Functional testing of mutant RHEB in vertebrate animal models indicates pathway hyperactivation with a concomitant increase in cell and head size, aberrant neuronal migration, and induction of seizures, concordant with the human phenotype. This study reveals that tight control of brain volume is exerted through a large community of mTOR-related genes. Human brain volume can be altered, by either rare disruptive events causing hyperactivation of the pathway, or through the collective effects of common alleles.

Advancement in the routine identification of anaerobic bacteria by MALDI-TOF mass spectrometry.

We evaluated matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) Biotyper as a tool for the identification of anaerobic bacteria compared with 500 base-pair (bp) 16S ribosomal ribonucleic acid (rRNA) gene sequencing analysis, which is considered to be the "gold standard" method. A total of 484 anaerobic bacteria were retrieved from the clinical specimens of 318 pediatric patients. Molecular identification resulted in 18 genera and 51 species. The most prevalent genus was Clostridium (76.85 %), with 70 % C. difficile isolates. The concordance and sensitivity determined by MALDI-TOF MS for C. difficile, the most prevalent species isolated, was 94.08 %, whereas the specificity was 100 %. For the other anaerobes, the sensitivity and specificity were 94.07 % and 81.82 %, respectively, with a concordance of 93.15 %. Low performance was observed for Propionibacterium acnes and Fusobacterium nucleatum, for which a dedicated pretreatment procedure should likely be set up. MALDI-TOF MS was shown to be a valid alternative for the fast and reliable identification of the most clinically relevant anaerobic bacteria; moreover, it is less time-consuming, the cost for reagents is minimized, and it does not require dedicated personnel.

Coinfection in acute gastroenteritis predicts a more severe clinical course in children.

The objectives of this study were to determine the incidence of enteric pathogens causing acute gastroenteritis (AGE) among hospitalized children in a large Italian hospital, to measure the incidence of coinfections, and to compare the clinical characteristics of those infected with one versus multiple agents. A prospective study was conducted from March 2010 to April 2011 at the Bambino Gesù Pediatric Hospital in Rome, Italy. All patients between 1 month and 16 years of age admitted to the Pediatric Department with a diagnosis of AGE were eligible for enrollment. Two stool samples for each patient were tested for gastrointestinal pathogens. We summarized the clinical severity of episodes, describing the duration of diarrhea, duration and frequency of vomiting, fever, and severity of dehydration. All the patients underwent medical evaluation with estimation of dehydration. One or more etiological agents were detected in 151 out of 232 patients (65.1%), while we did not detect any etiological agent in 81 (34.9%). Rotavirus was detected in 96 (63.6%), adenovirus in 17 (11.2%), norovirus in 7 (4.6%), toxin-producing Clostridium difficile in 23 (15.2%), Salmonella spp. in 15 (9.9%, B group in 12/15 and D group in 3/15), C. perfringens in 12 (7.9%), Campylobacter spp. in 6 (4%), and verotoxigenic Escherichia coli (VTEC) in 2 (1.3%). In 27 children out of 151 (17.9%), we found evidence of coinfection. Coinfection with rotavirus and toxin-producing C. difficile was the most common (63%). Children with coinfection had a more severe clinical presentation and had a higher probability to be severely dehydrated, independently of age and living community type.

Cases of cryptosporidiosis co-infections in AIDS patients: a correlation between clinical presentation and GP60 subgenotype lineages from aged formalin-fixed stool samples.

Nine cases of cryptosporidiosis co-infections in AIDS patients were clinically categorised into severe (patients 1, 3, 8 and 9), moderate (patients 4 and 5) and mild (patients 2, 6 and 7). Formalin-fixed faecal specimens from these patients were treated to obtain high quality DNA competent for amplification and sequencing of the 60-kDa glycoprotein (GP60) gene. Sequence analysis revealed that one patient was infected with Cryptosporidium hominis whereas the remaining eight patients were infected with C. parvum. Interestingly, the patients showing severe cryptosporidiosis harboured two subtypes within the C. parvum allelic family IIc (IIcA5G3 and IIcA5G3R2), whereas patients with moderate or mild infections showed various subtypes of the C. parvum allelic family IIa (IIaA14G2R1, IIaA15G2R1, IIaA17G3R1 and IIaA18G3R1). DNA extraction and genotyping of Cryptosporidium spp. is a challenging task on formalin-fixed stool samples, whose diagnostic outcome is age-dependent. The method herein reported represents a step forward routine diagnosis and improves epidemiology of HIV-related clinical cases. Due to the need to elucidate genetic richness of Cryptosporidium human isolates, this approach represents a useful tool to correlate individual differences in symptoms to subgenotyping lineages.