FGF-23 proteins containing the ADHR mutations are secreted, and produce polypeptides less sensitive to protease cleavage than wild-type FGF-23. Therefore, the ADHR mutations may protect FGF-23 from proteolysis, thereby potentially elevating circulating concentrations of FGF-23 and leading to phosphate wasting in ADHR patients.

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The gene mutated in autosomal dominant hypophosphatemic rickets (ADHR), a phosphate wasting disorder, has been identified as FGF-23, a protein that shares sequence homology with fibroblast growth factors (FGFs). Patients with ADHR display many of the clinical and laboratory characteristics that are observed in patients with oncogenic hypophosphatemic osteomalacia (OHO), a disorder thought to arise by the secretion of a phosphate wasting factor from different mesenchymal tumors. In the present studies, we therefore investigated whether FGF-23 is a secreted factor and whether it is abundantly expressed in OHO tumors. After transient transfection of OK-E, COS-7, and HEK293 cells with the plasmid encoding full-length FGF-23, all three cell lines efficiently secreted two protein species into the medium that were approximately 32 and 12 kDa upon SDS-PAGE and subsequent Western blot analysis using an affinity-purified polyclonal antibody to FGF-23. Furthermore, Northern blot analysis using total RNA from five different OHO tumors revealed extremely high levels of FGF-23 mRNA, and Western blot analysis of extracts from a sixth tumor detected the 32 kDa FGF-23 protein species. In summary, FGF-23, the gene mutated in ADHR, is a secreted protein and its mRNA is abundantly expressed by several different OHO tumors. Our findings indicate that FGF-23 may be a candidate phosphate wasting factor, previously designated "phosphatonin".

ADO2 is an uncommon sclerosing bone disorder with incomplete penetrance and variable expressivity. Positional candidate studies were performed to identify the gene responsible for ADO2. In 11 of 12 kindreds, five different missense mutations were identified in the ClCN7 gene, indicating the genetic basis and possible dominant negative mechanism for ADO2.Introduction: Autosomal dominant osteopetrosis, type II (ADO2) is an uncommon sclerosing bone disorder with a distinct radiographic appearance and unique clinical characteristics. We present the results from our genetic studies designed to identify the ADO2 gene through a positional candidate approach. Methods: Having identified 12 families with ADO2, we initially performed linkage studies in our seven largest kindreds and observed a summed maximum LOD score of 15.91 at marker D16S521 on chromosome 16p13.3. Critical meiotic recombination events further narrowed the putative gene region to a 7.6-cM area, which contains the candidate genes ATP6L and chloride channel 7 (ClCN7). We screened affected individuals from each ADO2 family for mutations in these genes using direct sequencing. Identified mutations were subsequently confirmed through direct sequencing or restriction fragment length polymorphism analysis. We then calculated the overall disease penetrance rate after all available at-risk family members were assessed for ClCN7 gene mutations. Results:No ATP6L mutations were identified in affected subjects. Subsequently, as ClCN7 gene mutations were being reported, we identified two novel (L213F, R762L) and three known (G215R, R286W, R767W) missense mutations in 11 kindreds. In our large sample, disease penetrance was 66% (62 clinically affected individuals/94 subjects with the gene mutation). To date, nine different mutations have been discovered in the ClCN7 gene in 22 of 23 ADO2 families studied. Conclusions:We conclude that mutations in the ClCN7 gene are responsible for ADO2 and that genetic heterogeneity is unlikely to exist in this disorder. Based on the preponderance of missense mutations and the knowledge that chloride channels probably function as dimers, it seems that heterozygous ClCN7 gene mutations may cause ADO2 through a dominant negative mechanism.

BackgroundSafety surveillance of widely used artemisinin-based combination therapy (ACT) is essential, but tolerability data in the over five years age group are largely anecdotal.MethodsTwo open-label, randomized trials were conducted in Nimba County, Liberia: i) the main tolerability trial with 1,000 Plasmodium falciparum malaria patients aged over five years (Study-T), and, ii) an efficacy trial with a secondary objective of collecting tolerability data among 300 children age six to 59 months (Study-E). In both studies patients were randomized to fixed-dose artesunate-amodiaquine (ASAQ Winthrop®) or artemether-lumefantrine (AL, Coartem®), respectively. Clinical- and laboratory-adverse events (AEs) were recorded until day 28.ResultsStudy-T: most patients experienced at least one AE. Severe AEs were few, primarily asymptomatic blood system disorders or increased liver enzyme values. No treatment or study discontinuation occurred. Mild or moderate fatigue (39.8% vs 16.3%, p < 0.001), vomiting (7.1% vs 1.6%, p < 0.001), nausea (3.2% vs 1.0%, p = 0.01), and anaemia (14.9% vs 9.8%, p = 0.01) were more frequently recorded in the ASAQ versus AL arm. Study-E: mild or moderate AEs were common, including anaemia, fatigue, vomiting or diarrhoea. The few severe events were asymptomatic blood system disorders and four clinical events (pneumonia, malaria, vomiting and stomatitis).ConclusionBoth ASAQ and AL were well tolerated in patients of all age groups. No unexpected AEs occurred. Certain mild or moderate AEs were more frequent in the ASAQ arm. Standardised safety surveillance should continue for all forms of ACT.Trial registrationThe protocols were registered with Current Controlled Trials, under the identifier numbers ISRCTN40020296, ISRCTN51688713, (http://www.controlled-trials.com).

SummaryBackgroundWHO recommends combinations of an artemisinin derivative plus an antimalarial drug of longer half-life as treatment options for uncomplicated Plasmodium falciparum infection. In Africa, artemether–lumefantrine is the most widely used artemisinin-based combination therapy, whereas artesunate–mefloquine is used infrequently because of a perceived poor tolerance to mefloquine. WHO recommends reconsideration of the use of artesunate–mefloquine in Africa. We compared the efficacy and safety of fixed-dose artesunate–mefloquine with that of artemether–lumefantrine for treatment of children younger than 5 years with uncomplicated P falciparum malaria.MethodsWe did this multicentre, phase 4, open-label, non-inferiority trial in Burkina Faso, Kenya, and Tanzania. Children aged 6–59 months with uncomplicated malaria were randomly assigned (1:1), via a computer-generated randomisation list, to receive 3 days' treatment with either one or two artesunate–mefloquine tablets (25 mg artesunate and 55 mg mefloquine) once a day or one or two artemether–lumefantrine tablets (20 mg artemether and 120 mg lumefantrine) twice a day. Parasitological assessments were done independently by two microscopists who were blinded to treatment allocation. The primary outcome was the PCR-corrected rate of adequate clinical and parasitological response (ACPR) at day 63 in the per-protocol population. Non-inferiority was shown if the lower limit of the 95% CI for the difference between groups was greater than −5%. Early vomiting was monitored and neuropsychiatric status assessed regularly during follow-up. This study is registered with ISRCTN, number ISRCTN17472707, and the Pan African Clinical Trials Registry, number PACTR201202000278282.Findings945 children were enrolled and randomised, 473 to artesunate–mefloquine and 472 to artemether–lumefantrine. The per-protocol population consisted of 407 children in each group. The PCR-corrected ACPR rate at day 63 was 90·9% (370 patients) in the artesunate–mefloquine group and 89·7% (365 patients) in the artemether–lumefantrine group (treatment difference 1·23%, 95% CI −2·84% to 5·29%). At 72 h after the start of treatment, no child had detectable parasitaemia and less than 6% had fever, with a similar number in each group (21 in the artesunate–mefloquine group vs 24 in the artemether–lumefantrine group). The safety profiles of artesunate–mefloquine and artemether–lumefantrine were similar, with low rates of early vomiting (71 [15·3%] of 463 patients in the artesunate–mefloquine group vs 79 [16·8%] of 471 patients in the artemether–lumefantrine group in any of the three dosing days), few neurological adverse events (ten [2·1%] of 468 vs five [1·1%] of 465), and no detectable psychiatric adverse events.InterpretationArtesunate–mefloquine is effective and safe, and an important treatment option, for children younger than 5 years with uncomplicated P falciparum malaria in Africa.FundingAgence Française de Développement, France; Department for International Development, UK; Dutch Ministry of F...

BackgroundProspective efficacy monitoring of anti-malarial treatments is imperative for timely detection of resistance development. The in vivo efficacy of artesunate-amodiaquine (ASAQ) fixed-dose combination (FDC) was compared to that of artemether-lumefantrine (AL) among children aged six to 59 months in Nimba County, Liberia, where Plasmodium falciparum malaria is endemic and efficacy data are scarce.MethodsAn open-label, randomized controlled non-inferiority trial compared the genotyping adjusted day 42 cure rates of ASAQ FDC (ASAQ Winthrop®) to AL (Coartem®) in 300 children aged six to 59 months with uncomplicated falciparum malaria. Inclusion was between December 2008 and May 2009. Randomization (1:1) was to a three-day observed oral regimen (ASAQ: once a day; AL: twice a day, given with fatty food). Day 7 desethylamodiaquine and lumefantrine blood-concentrations were also measured.ResultsThe day 42 genotyping-adjusted cure rate estimates were 97.3% [95% CI: 91.6-99.1] for ASAQ and 94.2% [88.1-97.2] for AL (Kaplan-Meier survival estimates). The difference in day 42 cure rates was −3.1% [upper limit 95% CI: 1.2%]. These results were confirmed by observed proportion of patients cured at day 42 on the per-protocol population. Parasite clearance was 100% (ASAQ) and 99.3% (AL) on day 3. The probability to remain free of re-infection was 0.55 [95% CI: 0.46-0.63] (ASAQ) and 0.66 [0.57-0.73] (AL) (p = 0.017).ConclusionsBoth ASAQ and AL were highly efficacious and ASAQ was non-inferior to AL. The proportion of patients with re-infection was high in both arms in this highly endemic setting. In 2010, ASAQ FDC was adopted as the first-line national treatment in Liberia. Continuous efficacy monitoring is recommended.Trial registrationThe protocols were registered with Current Controlled Trials, under the identifier numbers ISRCTN51688713, ISRCTN40020296.

Amodiaquine (AQ) is an antimalarial drug that was frequently combined with artesunate (AS) for the treatment of uncomplicated malaria due to Plasmodium falciparum and is now available as a fixed-dose combination. Despite its widespread use, the simultaneous pharmacokinetics in patients of AQ and its active metabolite, desethylamodiaquine (DAQ), were not characterized to date. The pharmacokinetics of AQ and DAQ in 54 adult patients receiving the AS/AQ combination were therefore investigated by the use of a population approach. AQ followed a 1-compartment model with first-order absorption and elimination, as well as a first-order and irreversible transformation into DAQ, which in turn followed a 2-compartment model with first-order elimination from its central compartment. The mean AQ apparent clearance and distribution volume were 3,410 liters/h and 39,200 liters, respectively. The mean terminal elimination half-life of DAQ was 211 h. Body weight was found to explain the interindividual variability of the apparent volume of distribution of AQ and the elimination rate constant of DAQ. A new dosage form consisting of a fixed-dose combination of AS and AQ was found to have no effect on the pharmacokinetic parameters of AQ and DAQ. All patients achieved parasite clearance within 4 days following the initiation of the treatment, which prevented investigation of the possible relationship between DAQ exposure and treatment outcome. This study provided the first simultaneous pharmacokinetic model for AQ and DAQ.Artemisinin-based combination therapy (ACT) is currently the optimal treatment for uncomplicated malaria due to Plasmodium falciparum (8). These combinations comprise an artemisinin derivative and a slowly eliminated partner drug. The former, which is fast acting and has a short half-life, provides a rapid reduction of the parasite biomass, while the latter provides effective concentrations over a prolonged period, allowing the clearance of the residual parasites (15, 23). The high efficacy of these combinations has been documented in several trials (2,7,10,13,14,17), and thus, ACTs are now the WHO recommended treatment for uncomplicated P. falciparum malaria.Artesunate (AS) plus amodiaquine (AQ) is one of these recommended ACTs. Amodiaquine is a 4-aminoquinoline which inhibits the glutathione-mediated degradation of ferriprotoporphyrin IX (6). Despite its own efficacy, amodiaquine is considered a prodrug of its active metabolite, desethylamodiaquine (DAQ), since DAQ is eliminated much more slowly than AQ and is therefore the main agent responsible for treatment efficacy (8).The PK parameters of the drug combined with the artemisinin derivative are of interest since they determine the length of treatment efficacy, as well as the beginning and duration of the selective window, i.e., the period corresponding to concentrations that are not high enough to be efficient against a new infection but are nevertheless sufficient to select resistant parasites (15,22).The pharmacokinetics (PK) of AQ/DAQ have been investigated...