Alu element insertion in PKLR gene as a novel cause of pyruvate kinase deficiency in Middle Eastern patients.

Pyruvate kinase deficiency (PKD) is the most frequent red blood cell enzyme abnormality of the glycolytic pathway and the most common cause of hereditary nonspherocytic hemolytic anemia. Over 250 PKLR-gene mutations have been described, including missense/nonsense, splicing and regulatory mutations, small insertions, small and gross deletions, causing PKD and hemolytic anemia of variable severity. Alu retrotransposons are the most abundant mobile DNA sequences in the human genome, contributing to almost 11% of its mass. Alu insertions have been associated with a number of human diseases either by disrupting a coding region or a splice signal. Here, we report on two unrelated Middle Eastern patients, both born from consanguineous parents, with transfusion-dependent hemolytic anemia, where sequence analysis revealed a homozygous insertion of AluYb9 within exon 6 of the PKLR gene, causing precipitous decrease of PKLR RNA levels. This Alu element insertion consists a previously unrecognized mechanism underlying pathogenesis of PKD.

Extensive error in the number of genes inferred from draft genome assemblies.

Current sequencing methods produce large amounts of data, but genome assemblies based on these data are often woefully incomplete. These incomplete and error-filled assemblies result in many annotation errors, especially in the number of genes present in a genome. In this paper we investigate the magnitude of the problem, both in terms of total gene number and the number of copies of genes in specific families. To do this, we compare multiple draft assemblies against higher-quality versions of the same genomes, using several new assemblies of the chicken genome based on both traditional and next-generation sequencing technologies, as well as published draft assemblies of chimpanzee. We find that upwards of 40% of all gene families are inferred to have the wrong number of genes in draft assemblies, and that these incorrect assemblies both add and subtract genes. Using simulated genome assemblies of Drosophila melanogaster, we find that the major cause of increased gene numbers in draft genomes is the fragmentation of genes onto multiple individual contigs. Finally, we demonstrate the usefulness of RNA-Seq in improving the gene annotation of draft assemblies, largely by connecting genes that have been fragmented in the assembly process.

Kinematic, kinetic, and blood lactate profiles of continuous and intraset rest loading schemes.

The purpose of this study was to investigate and compare the acute kinematic, kinetic, and blood lactate responses to continuous and intraset rest loading schemes that differed in terms of rest frequency but not total rest duration. Nine male subjects performed an isoinertial bench press task (6 repetition maximum load) with a continuous, an intraset rest equated by total rest time, volume, and load (ISRV), and an intraset rest equated by total rest time and load (ISRR) loading scheme. The scheme order was assigned in a block-randomized order with a minimum of 48 hours of recovery between testing sessions. Attached to the bar of the Smith machine was a linear position transducer that measured vertical displacement with an accuracy of 0.01 cm. Displacement data was sampled at 1,000 Hz and collected by a laptop computer running custom-built data acquisition software. Finger prick blood lactate samples were taken from the nondominant hand before exercise, immediately after exercise, and 5, 15 and 30 minutes after exercise. Blood glucose samples were taken before exercise only. It was observed that manipulating the rest period, by increasing the frequency but decreasing the length of each rest period, did not significantly influence the kinematics and kinetics associated with resistance training, but did have an effect on the postexercise blood lactate response when the load, rest duration, and training volume were equated (ISRV). This finding may be of practical significance if fatigue is important in strength development or conversely if power training requires minimal fatigue. It was also observed that increasing the frequency of the rest period enabled the subjects to perform a greater number of repetitions (ISRR), resulting in significantly greater kinematics, kinetics, and blood lactate accumulation.