BackgroundAgalsidase β is a form of enzyme replacement therapy for Fabry disease, a genetic disorder characterised by low α-galactosidase A activity, accumulation of glycosphingolipids and life-threatening cardiovascular, renal and cerebrovascular events. In clinical trials, agalsidase β cleared glycolipid deposits from endothelial cells within 6 months; clearance from other cell types required sustained treatment. We hypothesised that there might be a ‘lag time’ to clinical benefit after initiating agalsidase β treatment, and analysed the incidence of severe clinical events over time in patients receiving agalsidase β.MethodsThe incidence of severe clinical events (renal failure, cardiac events, stroke, death) was studied in 1044 adult patients (641 men, 403 women) enrolled in the Fabry Registry who received agalsidase β (average dose 1 mg/kg every 2 weeks) for up to 5 years.ResultsThe incidence of all severe clinical events was 111 per 1000 person-years (95% CI 84 to 145) during the first 6 months. After 6 months, the incidence decreased and remained stable within the range of 40–58 events per 1000 patient-years. The largest decrease in incidence rates was among male patients and those aged ≥40 years when agalsidase β was initiated.ConclusionsContrary to the expected increased incidence of severe clinical events with time, adult patients with Fabry disease had decreased incidence of severe clinical events after 6 months treatment with agalsidase β 1 mg/kg every 2 weeks.Trial registration numberNCT00196742.

Burosumab, a fully human monoclonal antibody to FGF23, is the only approved treatment for X-linked hypophosphatemia (XLH), a rare genetic disorder characterized by renal phosphate wasting and substantial cumulative musculoskeletal morbidity. During an initial 24-week randomized, controlled trial, 134 adults with XLH received burosumab 1 mg/kg (n = 68) or placebo (n = 66) every 4 weeks. After 24 weeks, all subjects received open-label burosumab until week 48. This report describes the efficacy and safety of burosumab during the open-label treatment period. From weeks 24-48, serum phosphorus concentrations remained normal in 83.8% of participants who received burosumab throughout and were normalized in 89.4% who received burosumab after placebo. By week 48, 63.1% of baseline fractures/pseudofractures healed fully with burosumab, compared with 35.2% with burosumab after placebo. In both groups, burosumab was associated with clinically significant and sustained improvement from baseline to week 48 in scores for patient-reported outcomes of stiffness, pain, physical function, and total distance walked in 6 min. Rates of adverse events were similar for burosumab and placebo. There were no fatal adverse events or treatment-related serious adverse events. Nephrocalcinosis scores did not change from baseline by more than one grade at either week 24 or 48. These data demonstrate that in participants with XLH, continued treatment with burosumab is well tolerated and leads to sustained correction of serum phosphorus levels, continued healing of fractures and pseudofractures, and sustained improvement in key musculoskeletal impairments.

Height is a complex genetic trait that involves multiple genetic loci. Recently, 44 loci associated with height were identified in Caucasian individuals by large-scale genome-wide association (GWA) studies. To identify genetic variants influencing height in the Korean population, we analyzed GWA data from 8842 Korean individuals and identified 15 genomic regions with one or more sequence variants associated with height (Po1Â10 À5 ). Of these, eight loci were newly identified in Koreans (SUPT3H, EXT1, FREM1, PALM2-AKAP2, NUP37-PMCH, IGF1, KRT20 and ANKRD60). The 15 significant loci account for approximately 1.0% of height variation, with a 3.7-cm difference between individuals with p8 height-increasing alleles (5.1%) and X19 height-increasing alleles (4.2%). We also examined the associations between height loci and idiopathic short stature (ISS). Five loci (SPAG17, KBTBD8, HHIP, HIST1H1D and ACAN) were significantly associated with ISS (uncorrected Po0.05), indicating that height-associated genes in the adult population are involved in extreme cases of short stature in children. This study validates previous reports of loci associated with human height and identified novel candidate regions involved in human growth and development.

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The lysyl oxidase-like protein 4 (LOXL4) is the latest member of the emerging family of lysyl oxidases, several of which were shown to function as copper-dependent amine oxidases catalyzing lysine-derived cross-links in extracellular matrix proteins. LOXL4 contains four scavenger receptor cysteine-rich domains in addition to the characteristic domains of the LOX family, including the copper-binding domain, the cytokine receptor-like domain, and the residues of the lysyl-tyrosyl quinone cofactor. In an effort to assess its amine oxidase activity, we expressed LOXL4 as recombinant forms attached with hexa-histidine residues at the carboxyl terminus by using an Escherichia coli expression system. The recombinant proteins were purified with nickel-chelating affinity chromatography and converted into enzymatically active forms by stepwise dialysis. The purified LOXL4 proteins showed ␤-aminopropionitrile-inhibitable activity of 0.022-0.032 units/mg toward a nonpeptidyl substrate, benzylamine. These results indicate that LOXL4, with the four scavenger receptor cysteine rich domains, may also function as an active amine oxidase. Availability of the pure and active forms of LOXL4 will be significantly helpful in functional studies related to substrate specificity and crystal structure of this amine oxidase, which should provide significant insights into functional differences within the LOX family members.

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