Detecting genomic mosaicism in "de novo" genetic epilepsy by amplicon-based deep sequencing.

AIM: To investigate the occurrence of mosaicism in epilepsy probands and their parents using amplicon-based deep sequencing (ADS). METHODS: Patients were recruited from the outpatient of Peking University First Hospital. Two hundred and sixty-four probands with pathogenic variants tested by next-generation sequencing (NGS) were enrolled. RESULTS: Mosaic variants were detected in seventeen disease-associated genes from 20 probands, 5 paternal, and 6 maternal parents. The frequency of mosaicism was 11.74% (31/264). Mosaicism in 11 genes was identified from 20 probands with the mutant allelic fractions (MAFs) of 12.95-38.00% in autosomal dominant genes. Five paternal mosaicisms were identified in genes with a MAF of 6.30-20.99%, and six maternal mosaic individuals with a MAF of 2.07-21.90%. Only four mosaic parents had milder seizure history. The affected sibling had the same phenotype consistent with that of the proband, who inherited the variant of SLC1A2 or STXBP1 from their unaffected mosaic mothers, respectively. INTERPRETATION: Mosaic phenomenon is not rare in families with epilepsy. Phenotypes of mosaic parents were milder or normal. Mosaicism detection is helpful to identify the mutation origin and it provides a theoretical basis for prenatal diagnosis of family reproduction. ADS is a reliable way of mosaicism detection for clinical application.

ATP1A3 mosaicism in families with alternating hemiplegia of childhood.

Alternating hemiplegia of childhood (AHC) is a rare and severe neurodevelopmental disorder characterized by recurrent hemiplegic episodes. Most AHC cases are sporadic and caused by de novo ATP1A3 pathogenic variants. In this study, the aim was to identify the origin of ATP1A3 pathogenic variants in a Chinese cohort. In 105 probands including 101 sporadic and 4 familial cases, 98 patients with ATP1A3 pathogenic variants were identified, and 96.8% were confirmed as de novo. Micro-droplet digital polymerase chain reaction was applied for detecting ATP1A3 mosaicism in 80 available families. In blood samples, four asymptomatic parents, including two paternal and two maternal, and one proband with a milder phenotype were identified as mosaicism. Six (7.5%) parental mosaicisms were identified in multiple tissues, including four previously identified in blood and two additional cases identified from paternal sperms. Mosaicism was identified in multiple tissues with varied mutant allele fractions (MAFs, 0.03%-33.03%). The results suggested that MAF of mosaicism may be related to phenotype severity. This is the first systematic report of ATP1A3 mosaicism in AHC and showed mosaicism as an unrecognized source of previously considered "de novo" AHC. Identifying ATP1A3 mosaicism provides more evidence for estimating recurrence risk and has implications in genetic counseling of AHC.

Effect of Surface Ionization of Doped MnO2 on Capacitive Deionization Efficiency.

Associating MnO2 with carbonaceous supports profoundly enhances capacitive deionization (CDI) efficiency. A fundamental question of how the surface chemistry of MnO2 itself influences CDI efficiency is not yet fully understood. In this study, the effect of surface ionization on the CDI efficiencies of Fe-, Co-, and Ni-doped α-MnO2 (<0.1 mol %) as a model cathode material was studied. A pattern that CDI efficiency decreased with increasing negative surface charge density resulting from surface deprotonation was noted. This is likely attributed to the appreciable co-ion expulsion occurring at a highly ionized surface in the mesopores of MnO2. It is thus concluded that the combination of surface charge modification and a microporous environment would be important for CDI efficiency enhancement by minimizing co-ion exclusion effect. In the former case, structural stress adjustment by doping elements would be a practical route to regulate the p Ka1 and p Ka2 values and consequently the degree of surface ionization of MnO2.

[ATP1A3 gene mutations in patients with alternating hemiplegia of childhood].

OBJECTIVE: To analyze the ATP1A3 mutations in patients with alternating hemiplegia of childhood (AHC) and recognize its value in diagnosing atypical cases. METHOD: Data of all AHC patients seen at Peking University First Hospital from August 2005 to November 2014 were prospectively collected. Clinical information of the AHC patients and their family members were collected and analyzed. Genomic DNAs were extracted from their peripheral blood. Mutations in ATP1A3 were screened by Sanger sequencing after PCR. RESULT: A total of 78 AHC patients were recruited, including 50 males and 28 females. Only three patients had family history of AHC. The first family case had affected mother with AHC; the second family case was the older one of a monozygotic male twins with AHC but their parents were normal; the third family case had a sister with AHC but their parents were normal. The age of onset ranged from six hours to eight years and six months (median: 4 months). According to the Aicardi's clinical diagnostic criteria, 72 patients were considered as typical AHC cases and the other six patients were considered as atypical AHC cases for their age of onset was older than 18 months. Twenty-seven different missense ATP1A3 mutations were detected in 71 (91.0%, 71/78) patients with AHC, including 66 typical and 5 atypical cases. 11 novel ATP1A3 mutations were first reported. ATP1A3 mutations were identified in the three AHC cases with family history. Parental analysis verified that the ATP1A3 mutation of 63 patients (95.5%, 63/66) were de novo origin except lack of five unavailable maternal or paternal genomic DNA. Mutation D801N was found in 20 cases (28.2%), and E815K in 12 cases (16.9%). In the six atypical AHC patients, ATP1A3 mutations were detected in five of them. CONCLUSION: ATP1A3 was the major causative gene of AHC, and mutations were identified as de novo mostly. ATP1A3 mutations in AHC had mutational hotspot, and the most common mutations were D801N and E815K. ATP1A3 mutation screening is helpful for the genetic and definite diagnosis of the atypical AHC cases.

Determination of geniposide in adjuvant arthritis rat plasma by ultra-high performance liquid chromatography tandem mass spectrometry method and its application to oral bioavailability and plasma protein binding ability studies.

A specific, sensitive and high throughput ultra-high performance liquid chromatography-electrospray ionization tandem mass spectrometric method (UHPLC-ESI-MS/MS) was established and validated to assay geniposide (GE), a promising anti-inflammatory drug, in adjuvant arthritis rat plasma: application to pharmacokinetic and oral bioavailability studies and plasma protein binding ability. Plasma samples were processed by de-proteinised with ice-cold methanol and separated on an ACQUITY UPLC™ HSS C18 column (100 mm × 2.1mm i.d., 1.8 µm particle size) at a gradient flow rate of 0.2 mL/min using acetonitrile-0.1% formic acid in water as mobile phase, and the total run time was 9 min. Mass detection was performed in selected reaction monitoring (SRM) mode with negative electro-spray ionization includes the addition of paeoniflorin (Pae) as an internal standard (IS). The mass transition ion-pair was followed as m/z 387.4 → 122.4 for GE and m/z 479.4 → 449.0 for IS. The calibration curves were linear over the concentration range of 2-50,000 ng/mL with lower limit of quantification of 2 ng/mL. The intra-day and inter-day precisions (RSD, %) of the assay were less than 8.4%, and the accuracy was within ± 6.4% in terms of relative error (RE). Extraction recovery, matrix effect and stability were satisfactory in adjuvant arthritis rat plasma. The UHPLC-ESI-MS/MS method was successfully applied to a pharmacokinetic study of GE after oral administration of depurated GE at 33, 66, 132 mg/kg and intravenous injection at 33, 66, 132 mg/kg in adjuvant arthritis (AA) rats. In addition, it was found that GE has rapid absorption and elimination, low absolute bioavailability, high plasma protein binding ability in AA rats after oral administration within the tested dosage range. It suggested that GE showed slow distribution into the intra- and extracellular space, and the binding rate was not proportionally dependent on plasma concentration of GE when the concentration of GE was below 5.0 µg/mL.

Tibetans at extreme altitude.

Between 1960 and 2003, 13 Chinese expeditions successfully reached the summit of Chomolungma (Mt Everest or Sagarmatha). Forty-five of the 80 summiteers were Tibetan highlanders. During these and other high-altitude expeditions in Tibet, a series of medical and physiological investigations were carried out on the Tibetan mountaineers. The results suggest that these individuals are better adapted to high altitude and that, at altitude, they have a greater physical capacity than Han (ethnic Chinese) lowland newcomers. They have higher maximal oxygen uptake, greater ventilation, more brisk hypoxic ventilatory responses, larger lung volumes, greater diffusing capacities, and a better quality of sleep. Tibetans also have a lower incidence of acute mountain sickness and less body weight loss. These differences appear to represent genetic adaptations and are obviously significant for humans at extreme altitude. This paper reviews what is known about the physiologic responses of Tibetans at extreme altitudes.