There are selective differences between the BALP isoforms in CRF compared with healthy adults. The commercial BALP immunoassays are comparable with each other but are unable to distinguish the BALP isoform-specific differences in CRF patients.

Our results have identified three novel HRPT2 mutations (two germline and one somatic). The Asp379Asn mutation is likely to disrupt interaction with the human homologue of the yeast Paf1 complex, and the demonstration of combined germline and somatic HRPT2 mutations in a parathyroid tumour provide further evidence for the tumour suppressor role of the HRPT2 gene.

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Alkaline phosphatase (ALP) is a glycoprotein and functions as an ectoenzyme attached to the cell membrane by a hydrophobic glycosyl-phosphatidylinositol (GPI) anchor. Three bone ALP (BALP) isoforms in human serum were separated and quantitated by high-performance liquid chromatography. B/I, a minor fraction, is composed on average of bone (70%) and intestinal (30%) ALP, and two major isoforms, B1 and B2. Treatment with GPI-specific phospholipase C (GPI-PLC) did not influence the activities or retention times for B1 and B2, indicating that the biochemical differences between B1 and B2 are likely to be due to different glycosylation patterns. The B/I fraction in serum, on average 4% of total ALP, was found to be composed of B1 and B2 isoforms, each with an intact hydrophobic GPI cell membrane anchor. We investigated the origin of these three BALP isoforms and osteocalcin in human femora from five healthy individuals (four males), mean age 51 years, obtained from a tissue bank. Bone was sampled from three sites: cortical bone, trabecular bone from the diaphysis, and trabecular bone from the greater trochanter. Trabecular bone, from both sites, had higher BALP activities compared with cortical bone. Conversely, the osteocalcin content of cortical bone was more than 3-fold greater than that of trabecular bone. Cortical bone had approximately 2-fold higher activity of B1 compared with B2, whereas trabecular bone had ∼2-fold higher activity of B2 compared with B1. We observed a previously undescribed BALP isoform (B1x) in all bone samples. B1x was also observed in sera from some patients (60%) with severe renal insufficiency and on chronic dialysis therapy (n = 20). The isoforms of BALP may provide information relating to bone metabolism within specific bone

To review whether osteoporosis in the absence of vertebral fracture (VFX) affects health-related quality of life (HRQoL), a systematic search of the main literature databases for HRQoL in patients with osteoporosis without VFX was undertaken. This was undertaken. This identified 1,327 articles as potentially relevant to the review. After screening of abstracts and reviewing 168 articles in detail, 27 were considered relevant. HRQoL data were extracted and collated into tables and, where possible, were converted into normative scores and further analysed. Data relating to the associations between HRQoL and bone mineral density (BMD) were also collated. Of the 27 articles included, only 5 directly compared osteoporosis without VFX with a control group (BMD T-score > -1.0, without VFX). Extracted raw data from 21 articles demonstrated that patients with osteoporosis without VFX had clinically relevant reductions in role physical, general health, vitality, mental health domains and the mental component summary score, using SF36. Using Qualeffo-41, pain and physical function were worse in these patients. Also, HRQoL was related to upper femur, but not lumbar spine BMD. HRQoL data in patients with osteoporosis without VFX are limited and variable but suggest that HRQoL is adversely affected by osteoporosis in the absence of VFX. The association of lower BMD and worse HRQoL suggests that more attention should be paid to HRQoL in those without VFX. Future studies are needed to investigate HRQoL in patients with osteoporosis in the absence of fracture, controlling for co-morbidities and social and economic status.