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Context Vitamin D status is usually assessed by serum total 25-hydroxyvitamin D (t25-OHD). Whether free 25-hydroxyvitamin D measures better correlate with various clinical outcomes is unclear. Objective To identify correlations between t25-OHD, calculated and direct measures of free 25-OHD, and to identify associations of these measures with other outcomes in children, across the 6 common GC haplotypes. Design Healthy urban-dwelling children underwent measurement of relevant variables. Setting Academic medical center. Participants The study included 203 healthy, urban-dwelling children, aged 6 months to 10 years, predominantly of Hispanic background and representative of all common GC haplotypes. Intervention None. Main Outcome Measures Total and free 25-OHD and 1,25(OH)2D, calcium, phosphate, parathyroid hormone (PTH), glucose, insulin, aldosterone, and renin. Results Mean t25-OHD [26.3 ± 6.7ng/ml; 65.8 ± 16.8nmol/L] were lowest in the GC2 genotype. Mean t1,25(OH)2D [57.6 ± 16.5pg/ml; 143.9 ± 41.3pmol/L], were lowest in GC1f/1f, GC1f/2, and GC2/2 groups. T25-OHD correlated strongly with calculated free 25-OHD (cf25-OHD) (r = 0.89) and moderately with directly measured free 25-OHD (dmf25-OHD) (r = 0.69). Cf25-OHD correlated with dmf25-OHD (r = 0.69) (P Conclusions Measures of circulating total and free 25-OHD are comparable measures of vitamin D status in heathy children. Correlations are similar with other outcome variables, however t25-OHD remains the strongest correlate of circulating PTH and other variables. These data argue against routine refinement of the t25-OHD measure using currently available assessments of free 25-OHD. Clinical Trial Information Clinicaltrials.gov registration no: NCT01050387 (January 15, 2010).

Objective The aim of this study was to analyze variants of the gene glial cells missing-2 (GCM2), encoding a parathyroid cell-specific transcription factor, in familial hypoparathyroidism and in familial isolated hyperparathyroidism (FIHP) without and with parathyroid carcinoma. Design We characterized 2 families with hypoparathyroidism and 19 with FIHP in which we examined the mechanism of action of GCM2 variants. Methods Leukocyte DNA of hypoparathyroid individuals was Sanger sequenced for CASR, PTH, GNA11 and GCM2 mutations. DNA of hyperparathyroid individuals underwent MEN1, CDKN1B, CDC73, CASR, RET and GCM2 sequencing. The actions of identified GCM2 variants were evaluated by in vitro functional analyses. Results A novel homozygous p.R67C GCM2 mutation which failed to stimulate transcriptional activity in a luciferase assay was identified in affected members of two hypoparathyroid families. Oligonucleotide pull-down assay and in silico structural modeling indicated that this mutant had lost the ability to bind the consensus GCM recognition sequence of DNA. Two novel (p.I383M and p.T386S) and one previously reported (p.Y394S) heterozygous GCM2 variants that lie within a C-terminal conserved inhibitory domain were identified in three affected individuals of the hyperparathyroid families. One family member, heterozygous for p.I138M, had parathyroid carcinoma (PC), and a heterozygous p.V382M variant was found in another patient affected by sporadic PC. These variants exerted significantly enhanced in vitrotranscriptional activity, including increased stimulation of the PTH promoter. Conclusions We provide evidence that two novel GCM2 R67C inactivating mutations with an inability to bind DNA are causative of hypoparathyroidism. Additionally, we provide evidence that two novel GCM2 variants increased transactivation of the PTH promoter in vitro and are associated with FIHP. Furthermore, our studies suggest that activating GCM2 variants may contribute to facilitating more aggressive parathyroid disease.

Objective GC/DBP effects on response to vitamin D supplementation have not been well-studied. Thus we assessed free and total 25-OHD after vitamin D treatment across the six common GC haplotypes. Design This double-blind, randomized study compared two vitamin D3 doses in healthy, urban-dwelling 6-month to 10-year-old children at-risk for vitamin D deficiency. Randomization was stratified by GC haplotype. Methods Children were randomized to receive 2800 or 7000 International Units of vitamin D3 weekly. 25-OHD and 1,25(OH)2D were sampled at baseline and after 1–6 months of supplementation. Results and conclusions One hundred ninety-two of 225 enrolled subjects completed the study. After one month, total 25-OHD increased with both doses and were higher with 7000 IU/week (85.5 ± 22.8 nmol/L) compared to 2800 IU/week (76.8 ± 18.0 nmol/L), despite equivalent baseline levels. No further significant increase occurred at 6 months (89.8 ± 35.5 and 74.3 ± 18.3 nmol/L, respectively). Free 25-OHD similarly changed. 25-OHD differed among GC groups at baseline. Although no significant effects of individual GC haplotypes on incremental changes were evident, a trend toward an effect of combined 'at risk' GC alleles on response was evident (P = 0.06). Total 1,25(OH)2D showed modest increases, moreso with the larger dose. In urban-dwelling children at-risk for vitamin D deficiency, 1 month of vitamin D3 2800 IU/week increased 25-OHD across all GC haplotype groups, and somewhat enhanced with 7000 IU/week with no further significant increases after 6 months of supplementation. Free 25-OHD measures offer no monitoring advantage over total 25-OHD.

The tree-based scan statistic (TreeScan; Martin Kulldorff, Harvard Medical School, Boston, Massachusetts) is a data-mining method that adjusts for multiple testing of correlated hypotheses when screening thousands of potential adverse events for signal identification. Simulation has demonstrated the promise of TreeScan with a propensity score (PS)-matched cohort design. However, it is unclear which variables to include in a PS for applied signal identification studies to simultaneously adjust for confounding across potential outcomes. We selected 4 pairs of medications with well-understood safety profiles. For each pair, we evaluated 5 candidate PSs with different combinations of 1) predefined general covariates (comorbidity, frailty, utilization), 2) empirically selected (data-driven) covariates, and 3) covariates tailored to the drug pair. For each pair, statistical alerting patterns were similar with alternative PSs (≤11 alerts in 7,996 outcomes scanned). Inclusion of covariates tailored to exposure did not appreciably affect screening results. Inclusion of empirically selected covariates can provide better proxy coverage for confounders but can also decrease statistical power. Unlike tailored covariates, empirical and predefined general covariates can be applied “out of the box” for signal identification. The choice of PS depends on the level of concern about residual confounding versus loss of power. Potential signals should be followed by pharmacoepidemiologic assessment where confounding control is tailored to the specific outcome(s) under investigation.

Glycans represent a promising but only marginally accessed source of cancer markers. We previously reported the development of a molecularly bottom-up approach to plasma and serum (P/S) glycomics based on glycan linkage analysis that captures features such as α2–6 sialylation, β1–6 branching, and core fucosylation as single analytical signals. Based on the behavior of P/S glycans established to date, we hypothesized that the alteration of P/S glycans observed in cancer would be independent of the tissue in which the tumor originated yet exhibit stage dependence that varied little between cancers classified on the basis of tumor origin. Herein, the diagnostic utility of this bottom-up approach as applied to lung cancer patients (n = 127 stage I; n = 20 stage II; n = 81 stage III; and n = 90 stage IV) as well as prostate (n = 40 stage II), serous ovarian (n = 59 stage III), and pancreatic cancer patients (n = 15 rapid autopsy) compared to certifiably healthy individuals (n = 30), nominally healthy individuals (n = 166), and risk-matched controls (n = 300) is reported. Diagnostic performance in lung cancer was stage-dependent, with markers for terminal (total) fucosylation, α2–6 sialylation, β1–4 branching, β1–6 branching, and outer-arm fucosylation most able to differentiate cases from controls. These markers behaved in a similar stage-dependent manner in other types of cancer as well. Notable differences between certifiably healthy individuals and case-matched controls were observed. These markers were not significantly elevated in liver fibrosis. Using a Cox proportional hazards regression model, the marker for α2–6 sialylation was found to predict both progression and survival in lung cancer patients after adjusting for age, gender, smoking status, and stage. The potential mechanistic role of aberrant P/S glycans in cancer progression is discussed.

Background The occurrence of parathyroid carcinoma in multiple endocrine neoplasia type I (MENI) is rare and the 15 cases of malignant parathyroid tumor reported so far have been associated with MENI in individuals and not with multiple members within a family. Methods We report on a 61-year-old male, operated for a 7.3 cm parathyroid carcinoma infiltrating the esophagus. In his brother, a 4.6 cm parathyroid carcinoma was diagnosed histologically, while in the daughter, neck ultrasonography revealed 2 extrathyroidal nodules, yet to be excised. Results Screening of the MEN1 gene identified a known germline heterozygous missense mutation (c.1252G>A; p.D418N) in exon 9, in all affected subjects. Conclusions The occurrence of parathyroid carcinoma in more than one affected member of a single MEN1 family represents the first reported familial case. This suggests that additional constitutional genetic mutations may contribute to the variation in malignant potential and clinical behavior of parathyroid tumors in MEN1.

Background: Linkage disequilibrium (LD) is the non-random association between alleles at different loci and remains important for disease mapping studies in humans. A common measure of LD is the sample correlation between indicator variables for alleles at the 2 loci. Knowledge of LD estimate precision may help inform biomedical decisions based on those estimates. Objectives and Methods: Variance formulae are obtained for correlation measures of LD in 4 scenarios. These scenarios include data in the form of gametic and genotypic counts, with different assumptions used to simplify the analysis. Results: The formulae are expressed as polynomials (or ratios of polynomials) in higher-order disequilibrium coefficients with constants which are functions of the allele frequencies and Hardy-Weinberg disequilibrium coefficients. With genotypic data, the variance is the same as with gametic data when the phase is known and there is random mating. When the phase is unknown, the correlation LD has variance which is twice as large. Conclusions: Symbolic computation proved to be effective in facilitating algebraic derivations which would otherwise have been intractable.

We report that recessive inheritance of a post-GPI attachment to proteins 2 (PGAP2) gene variant results in the hyperphosphatasia with neurologic deficit (HPMRS) phenotype described by Mabry et al., in 1970. HPMRS, or Mabry syndrome, is now known to be one of 21 inherited glycosylphosphatidylinositol (GPI) deficiencies (IGDs), or GPI biosynthesis defects (GPIBDs). Bi-allelic mutations in at least six genes result in HPMRS phenotypes. Disruption of four phosphatidylinositol glycan (PIG) biosynthesis genes, PIGV, PIGO, PIGW and PIGY, expressed in the endoplasmic reticulum, result in HPMRS 1, 2, 5 and 6; disruption of the PGAP2 and PGAP3 genes, necessary for stabilizing the association of GPI anchored proteins (AP) with the Golgi membrane, result in HPMRS 3 and 4. We used exome sequencing to identify a novel homozygous missense PGAP2 variant NM_014489.3:c.881C > T, p.Thr294Met in two index patients and targeted sequencing to identify this variant in an unrelated patient. Rescue assays were conducted in two PGAP2 deficient cell lines, PGAP2 KO cells generated by CRISPR/Cas9 and PGAP2 deficient CHO cells, in order to examine the pathogenicity of the PGAP2 variant. First, we used the CHO rescue assay to establish that the wild type PGAP2 isoform 1, translated from transcript 1, is less active than the wild type PGAP2 isoform 8, translated from transcript 12 (alternatively spliced to omit exon 3). As a result, in our variant rescue assays, we used the more active NM_001256240.2:c.698C > T, p.Thr233Met isoform 8 instead of NM_014489.3:c.881C > T, p.Thr294Met isoform 1. Flow cytometric analysis showed that restoration of cell surface CD59 and CD55 with variant PGAP2 isoform 8, driven by the weak (pTA FLAG) promoter, was less efficient than wild type isoform 8. Therefore, we conclude that recessive inheritance of c.881C > T PGAP2, expressed as the hypomorphic PGAP2 c.698C > T, p.Thr233Met isoform 8, results in prototypical Mabry phenotype, HPMRS3 (GPIBD 8 [MIM: 614207]). This study highlights the need for long-term follow up of individuals with rare diseases in order to ensure that they benefit from innovations in diagnosis and treatment.

Aims To investigate the associations of 25-hydroxyvitamin D (25(OH)D) with insulin resistance (IR), beta-cell function and metabolic syndrome (MetS) in a First Nations population. Methods We conducted a cross-sectional analysis using data from the Sandy Lake Health and Diabetes Project (2003–2005). A total of 390 participants (>12y) were assessed for 25(OH)D, fasting glucose, insulin, lipids, blood pressure, inflammatory markers, anthropometric and lifestyle variables and a 75-g oral glucose tolerance test was administered. IR was calculated using the Matsuda insulin sensitivity index (IS OGTT ) and the computational homeostasis model assessment of IR (HOMA2-IR). Beta-cell function was calculated using the insulinogenic index (IGI) divided by HOMA-IR (IGI/IR) and the insulin secretion sensitivity index-2 (ISSI-2). The 2009 harmonized criteria were used to define MetS. Results Higher 25(OH)D was associated with a decreased prevalence of dysglycemia (OR=0.71 95% CI, 0.51–0.97 per SD increase). In addition, there were significant associations of 25(OH)D with measures of insulin action (IS OGTT ; beta=0.31; 95% CI, 0.12, 0.49; HOMA2-IR; beta=−29; 95% CI −0.46, −0.11 and beta-cell function (ISSI-2; beta=0.15; 95% CI, 0.02, 0.28). The prevalence of MetS was 41%. There was a decreased risk (OR=0.73, 95% CI 0.56, 0.94) of MetS per SD increase in baseline 25(OH)D. Finally, there was a significant positive association of 25(OH)D with adiponectin (beta=0.16; 95% CI=0.01, 0.31). Conclusions These results support a potential role for vitamin D metabolism in the natural history of T2DM among Aboriginal Canadians, although carefully designed randomized trials will be required to establish causality.

Objectives We aimed to compare the associations of directly measured plasma free 25-hydroxyvitamin D [25(OH)D] and total 25(OH)D concentrations with insulin sensitivity (SI) and β-cell function in nondiabetic Hispanics and African Americans. We hypothesized that directly measured free 25(OH)D would be more strongly associated with these measures of glucose homeostasis and that associations would differ by race. Design We studied 1189 nondiabetic participants in the Insulin Resistance Atherosclerosis Study Family Study using data from baseline examinations from 2000 to 2002. SI, acute insulin response, and disposition index (DI) were determined from frequently sampled intravenous glucose tolerance tests. Plasma free and total 25(OH)D concentrations were measured by enzyme-linked immunosorbent assay and radioimmunoassay, respectively. Results The median concentrations of plasma free 25(OH)D were 3.46 pg/mL for Hispanics and 2.17 pg/mL for African Americans (P < 0.0001), whereas the median concentrations of plasma total 25(OH)D were 16 ng/mL for Hispanics and 10 ng/mL for African Americans (P < 0.0001). Plasma free and total 25(OH)D were both positively associated with SI and DI in generalized estimating equations adjusted for demographic and lifestyle factors. After further adjustment with body mass index, the associations were no longer statistically significant, except for a significant association between plasma free 25(OH)D and SI. There was no effect modification by ethnicity on any of the exposure-outcome associations. Conclusions Our data showed that plasma free 25(OH)D had a slightly stronger association with SI compared with plasma total 25(OH)D, although the difference was modest and there were no marked differences in the associations between Hispanics and African Americans.

Inactivating mutations of the multiple endocrine neoplasia 1 (MEN1) gene cause MEN1 syndrome, characterized by primary hyperparathyroidism (pHPT), and parathyroid and gastro-entero-pancreatic pituitary tumors. At present, only 14 cases of malignant parathyroid tumor have been associated with the syndrome, with 6 cases carrying an inactivating mutation of the MEN1 gene. The present study presents the case of a 48-year-old female who presented with multigland pHPT and multiple pancreatic lesions. The patient underwent surgery several times for the excision of parathyroid hyperplasia, carcinoma and adenoma. The MEN1 gene was screened, revealing three variants (in cis) at the intron/exon 3 boundary (IVS2-3G>C, c.497A>T and c.499G>T) detected on the DNA of the proband, not shared by her relatives. RNA sequencing revealed that the IVS2-3C>G variant caused the skipping of the exon 3. Therefore, the present study reports on a novel rare association of MEN1 syndrome and parathyroid carcinoma. The reported splicing mutation was previously identified in subjects who always developed malignant lesions; thus, a possible genotype-phenotype association may be considered.

Background Potential vitamin D–related influences on inflammatory diseases such as asthma are controversial, including the suggestion that vitamin D insufficiency is associated with increased asthma morbidity. Vitamin D–binding protein transports vitamin D metabolites in the circulation. Single nucleotide polymorphisms in the GC gene encoding vitamin D–binding protein are associated with circulating vitamin D metabolite levels in healthy infants and toddlers. Objective To test the hypothesis that GC single nucleotide polymorphisms encoding the D432E and T436K variants predict subsequent development of asthma in healthy children. Methods A retrospective medical record review was performed to determine the development of asthma in 776 children in whom GC genotype, vitamin D–binding protein concentration, and circulating 25-hydroxyvitamin D had been determined at 6 to 36 months of age. Demographic and detailed current clinical data were collected and criteria for asthma were recorded. Results GC genotype was available for 463 subjects. After an initial analysis of all subject data, the analysis was limited to the predominant Hispanic population (72.1%) to minimize potential confounding effects of ethnicity. Asthma was diagnosed in 87 children (26%). Subjects with the GC genotype encoding the ET/ET (Gc1s/Gc1s) variant had lower odds of developing asthma, representing a protective effect compared with subjects with the DT/DT (Gc1f/Gc1f) variant. Conclusion In the Hispanic population of inner-city New Haven, Connecticut, the ET/ET (Gc1s/Gc1s) genotype of vitamin D–binding protein might confer protection against the development of asthma compared with the wild-type genotype DT/DT (Gc1f/Gc1f).

Vitamin D insufficiency, as measured by 25-hydroxyvitamin D (25[OH]D) levels, has been associated with important health outcomes. The majority of vitamin D in circulation is bound to vitamin D–binding protein (DBP) and albumin, and recent genetic studies have demonstrated that serum DBP is a major determinant of 25(OH)D concentrations in adults. The impact of circulating DBP levels on vitamin D's biologic action, is unclear, but is of particular relevance to vitamin D epidemiology, because a lack of control for DBP levels could strongly influence the association of vitamin D with disease. Serum parathyroid hormone (PTH) levels can act as a biological readout of 25(OH)D activity. We therefore assessed the relationship between serum total and free 25(OH)D and PTH with and without adjusting for DBP, in 2073 subjects of European descent. Total 25(OH)D levels correlated positively (r = 0.19, p = 1.8 × 10−17) with DBP, whereas the free 25(OH)D correlated negatively (r = −0.14, p = 5.0 × 10−12). Total and free 25(OH)D levels correlated negatively with PTH (r = −0.29, p = 1.3 × 10−39; r = −0.26, p = 1.9 × 10−33, respectively). Including age, body mass index (BMI), sex, estimated glomerular filtration rate, calcium, and season of blood draw as covariates, total 25(OH)D levels were significantly associated with log-transformed PTH (lnPTH) levels (linear term: β = −0.010, p

Voriconazole is an important antifungal agent used to treat invasive fungal infections; however, its administration can be difficult because of the narrow range between the level required for therapeutic efficacy and the level at which there is risk for hepatic and neurological toxicity. The purpose of this study was to elucidate the relationships among oral dosage, voriconazole levels and liver enzyme levels among leukemia patients., INTRODUCTION: Voriconazole plasma concentrations have been correlated with oral dosing in healthy subjects, but have been poorly characterized in ill patients with hematological malignancies receiving intensive chemotherapy. METHODS: The relationship between orally administered voriconazole, plasma concentrations and liver toxicity was examined in a cohort of 69 primarily acute leukemia patients undergoing intensive chemotherapy. RESULTS: Oral administration of voriconazole was associated with significant interpatient variability, with voriconazole steady-state concentrations ranging from 0 μg/mL to 16.6 μg/mL. Approximately 20% of patients achieved steady-state concentrations

The calcium-sensing receptor (CaSR) is a G protein-coupled receptor encoded by a single copy gene. The human CASR gene spans ∼103-kb and has eight exons. Promoters P1 and P2 drive transcription of exons 1A and 1B, respectively, encoding alternative 5′-UTRs that splice to exon 2 encoding the common part of the 5′-UTR. Exons 2–7 encode the CaSR protein of 1078 amino acids. Functional elements responsive to 1,25-dihydroxyvitamin D, proinflammatory cytokines, and glial cells missing-2 are present in the CASR promoters. Evolutionarily, the exon structure, first seen in aquatic vertebrates, is well-conserved with a single linkage disequilibrium haplotype block for protein coding exons 2–7. Structural features of the human CaSR protein are: an N-terminal signal peptide (19 amino acids (aa)); an extracellular domain (∼600 aa) having a bi-lobed Venus Flytrap (VFT) domain with several Ca 2+ -binding sites; and a nine-cysteines domain that transduces the activation signal to the 7-transmembrane domain (250 aa) and the C-terminal tail (216 aa).

The vitamin D binding protein (DBP) is the major plasma carrier for vitamin D and its metabolites, but it is also an actin scavenger, and is the precursor to the immunomodulatory protein, Gc-MAF. Two missense variants of the DBP gene - rs7041 encoding Asp432Glu and rs4588 encoding Thr436Lys - change the amino acid sequence and alter the protein function. They are common enough to generate population-wide constitutive differences in vitamin D status, based on assay of the serum metabolite, 25-hydroxyvitamin D (25OHD). Whether these variants also influence the role of vitamin D in an immunologic milieu is not known. However, the issue is relevant, given the immunomodulatory effects of DBP and the role of protracted innate immune-related inflammation in response to tissue injury or repeated infection. Indeed, DBP and vitamin D may jointly or independently contribute to a variety of adverse health outcomes unrelated to classical notions of their function in bone and mineral metabolism. This review summarizes the reports to date of associations between DBP variants, and various chronic and infectious diseases. The available information leads us to conclude that DBP variants are a significant and common genetic factor in some common disorders, and therefore, are worthy of closer attention. In view of the heightened interest in vitamin D as a public health target, well-designed studies that look simultaneously at vitamin D and its carrier in relation to genotypes and adverse health outcome should be encouraged.

Summary Genotypic counts of paired relatives discordant for a complex late-onset disease are often used to test for genetic association. The power of the various statistical test options, when data on covariates are unavailable, has been the focus of recent research. Comparison of the Cochran-Armitage, Bhapkar, and McNemar tests indicates that none is superior to the others in all cases. Using an alternative approach, we found that the theoretical genotypic frequencies of the discordant pairs depend only on the penetrance odds ratios, after conditioning. These odds ratios can be estimated by maximizing a product binomial likelihood and provide insight into the mode of inheritance. We identified cases where exact maximum likelihood (ML) estimates can be explicitly obtained. This approach led us to two tests for association which depend on likelihood ratio (LR) or score statistics. We quantified the power of these tests analytically and examined their performance through simulation. We explored the utility of these tests with an example from the literature—the association between complement factor H (CFH) polymorphisms and age-related macular degeneration. The LR and Score tests serve as simple and effective ways of interpreting paired case-control data sets.

Background Inactivating mutations of CDC73 cause Hyperparathyroidism-Jaw Tumour syndrome (HPT-JT), Familial Isolated Hyperparathyroidism (FIHP) and sporadic parathyroid carcinoma. We conducted CDC73 mutation analysis in an HPT-JT family and confirm carrier status of the proband’s daughter. Methods The proband had primary hyperparathyroidism (parathyroid carcinoma) and uterine leiomyomata. Her father and daughter had hyperparathyroidism (parathyroid adenoma) but no other manifestations of HPT-JT. CDC73 mutation analysis (sequencing of all 17 exons) and whole-genome copy number variation (CNV) analysis was done on leukocyte DNA of the three affecteds as well as the proband’s unaffected sister. Results A novel deletion of exons 4 to 10 of CDC73 was detected by CNV analysis in the three affecteds. A novel insertion in the 5’UTR (c.-4_-11insG) that co-segregated with the deletion was identified. By in vitro assay the 5’UTR insertion was shown to significantly impair the expression of the parafibromin protein. Screening for the mutated CDC73 confirmed carrier status in the proband’s daughter and the biochemistry and ultrasonography led to pre-emptive surgery and resolution of the hyperparathyroidism. Conclusions A novel gross deletion mutation in CDC73 was identified in a three-generation HPT-JT family emphasizing the importance of including screening for large deletions in the molecular diagnostic protocol.

Primary hyperparathyroidism (PHPT) is associated with hypovitaminosis D as assessed by serum total 25-hydroxyvitamin D (TotalD) levels. The aim of this study is to evaluate whether this is also the case for the calculated bioavailable 25-hydroxyvitamin D (BioD) or free 25-hydroxyvitamin D (FreeD), and whether the vitamin D status is influenced by genetic background. We compared vitamin D status of 88 PHPT patients each with a matched healthy family member sharing genetic background, i.e., first-degree relative (FDR), or not, namely an in-law relative (ILR). We compared TotalD and vitamin D-binding protein (DBP), using the latter to calculate BioD and FreeD. We also genotyped two common DBP polymorphisms (rs7041 and rs4588) likely to affect the affinity for and levels of vitamin D metabolites. TotalD was lower (p

Objectives To assess allele frequency and potential predictive value of recurrent polymorphisms affecting warfarin metabolism in an unselected patient cohort attending an anticoagulant clinic (n = 186). Design and methods Genotyping of ten SNPs in five candidate genes ( VKORC1, CYP2C9, CALU, EPHX and GGCX ) was carried out by ABI PRISM SNaPshot® multiplex method. Results We confirm the association between high-frequency SNPs, VKORC1 c.-1639G>A and CYP2C9 *2/*3 and warfarin sensitivity, and contribute additional evidence that the VKORC1 p.Asp36Tyr variant is recurrent and independently associated with warfarin resistance in our population. Other SNPs made little contribution. Conclusion Warfarin sensitivity was predicted by known VKORC1 and CYP2C9 SNPs. However, resistance associated with p.Asp36Tyr in VKORC1 would not be predicted by the usual markers. Despite its relatively low frequency (3/186 or 1.6%) clinical considerations may warrant its inclusion in pharmacogenetic screening for initial warfarin dosing in clinic populations with a heterogeneous population base.

Background: Vitamin D, from diet and sunlight exposure, may be associated with reduced breast-cancer risk. This study investigated if candidate gene variants in vitamin D pathways are associated with breast cancer risk, or modify the associations between breast cancer and vitamin D exposure. Methods: Breast cancer cases aged 25 to 74 years were identified from the Ontario Cancer Registry (histopathologically confirmed and diagnosed 2002–2003) and population-based controls were identified through random digit dialing of Ontario households. Saliva (DNA) was available for 1,777 cases and 1,839 controls. Multivariate logistic regression was used to evaluate associations between 19 single nucleotide polymorphisms (SNP) in vitamin D related genes, including vitamin D binding protein (GC), vitamin D receptor (VDR), and cytochrome P450 type 24A1 (CYP24A1). Statistical interactions were assessed using the likelihood ratio test. Results: Some SNPs were found to be significantly associated with breast cancer risk. For example, breast cancer risk was associated with the GC rs7041 TT genotype (age-adjusted odds ratio (OR) = 1.23; 95% CI: 1.01, 1.51) and inversely with the VDR Fok1 (rs2228570) ff genotype (OR = 0.71; 95% CI: 0.57, 0.88). Few significant gene-environment interactions were observed between dietary vitamin D and genetic variants. Conclusion: Our study suggests certain vitamin D related genetic variants may influence breast-cancer risk and we found limited evidence that genetic variants modify the associations between vitamin D exposure and breast cancer risk. Impact: Variation in vitamin D-related genotypes may help to explain inconsistent results from previous epidemiologic studies and may lead to targeted prevention strategies. Cancer Epidemiol Biomarkers Prev; 20(8); 1708–17. ©2011 AACR.

Previous research indicates that circulating vitamin D levels are low in many otherwise healthy adults and that there is considerable seasonal variation in 25-hydroxyvitamin D [25(OH)D] concentrations at high latitudes. We examined seasonal variation in 25(OH)D levels in a sample of young adults of diverse ancestry living in the Greater Toronto Area. Three hundred and fifty-one (351) healthy young adults completed both a fall and winter visit during this study. The study was conducted over 2 y (y 1: fall 2007 to winter 2008 and y 2: fall 2008 to winter 2009). At both visits, each participant's serum 25(OH)D concentration was measured. Information was also obtained on skin pigmentation (measured via reflectometer), vitamin D intake, and extent of sun exposure. Overall, the serum 25(OH)D concentration was 54.4 ± 1.3 nmol/L in the fall and 38.4 ± 1.1 nmol/L in the winter. Concentrations differed among ancestral groups at both visits (P0.001), with South Asians and East Asians having substantially lower concentrations than Europeans. Skin pigmentation (r(2) = 0.14; P0.001), supplemental vitamin D intake (r(2) = 0.09; P0.001), sun exposure (r(2) = 0.04; P0.001), and study year (r(2) = 0.02; P = 0.017) were predictors of fall 25(OH)D concentrations. During the wintertime, serum 25(OH)D concentrations were associated with concentrations taken in the fall (r(2) = 0.45; P0.001), supplemental (r(2) = 0.15; P0.001) and dietary vitamin D intake (r(2) = 0.06; P0.001), and with study year (r(2) = 0.02; P = 0.009). Our study confirms that serum 25(OH)D concentrations undergo strong seasonal variation at high latitudes and are influenced by vitamin D intake, skin pigmentation, and sun exposure.

Persistent hyperphosphatasia associated with developmental delay and seizures was described in a single family by Mabry et al. 1970 (OMIM 239300), but the nosology of this condition has remained uncertain ever since. We report on five new patients (two siblings, one offspring of consanguineous parents, and two sporadic patients) that help delineate this distinctive disorder and provide evidence in favor of autosomal recessive inheritance. Common to all five new patients is facial dysmorphism, namely hypertelorism, a broad nasal bridge and a tented mouth. All patients have some degree of brachytelephalangy but the phalangeal shortening varies in position and degree. In all, there is a persistent elevation of alkaline phosphatase activity without any evidence for active bone or liver disease. The degree of hyperphosphatasia varies considerably (∼1.3–20 times the upper age-adjusted reference limit) between patients, but is relatively constant over time. In the first family described by Mabry et al. 1970, at least one member was found to have intracellular inclusions on biopsy of some but not all tissues. This was confirmed in three of our patients, but the inclusions are not always observed and the intracellular storage material has not been identified. © 2010 Wiley-Liss, Inc.

Obesity is a major risk factor for type 2 diabetes mellitus (T2DM), which is a significant health problem worldwide. Active disease is associated with low-grade chronic inflammation resulting in part from the activation of the innate immune system. In obesity, this activation leads to the release of pro-inflammatory cytokines such as tumor necrosis factor-α, interleukin-1β and interleukin-6 that block major anabolic cascades downstream of insulin signaling and thus disrupt insulin homeostasis and action. Cytokines also trigger the production of acute-phase reactants such as C-reactive protein, plasminogen activator inhibitor-1, serum amyloid-A, and haptoglobin. The elevated synthesis of pro-inflammatory cytokines and acute-phase proteins (inflammatory network) characterizes the early (or pre-clinical) stages of T2DM and exhibits a graded increase with the disease progression. Current evidence suggests that understanding inflammatory networks can point to new biomarkers that may permit capturing the interaction between genetic and environmental risk factors in the pathogenesis of T2DM. Such biomarkers have a significant public health potential in the prediction of disease occurrence beyond risk factors presently monitored, such as family history, lifestyle assessment and standard clinical chemistry profiles. Furthermore, inflammatory markers may assist in the evaluation of novel strategies for prevention, particularly in relation to micronutrients. This review discusses the current knowledge linking T2DM risk to inflammatory signaling pathways interacting with the innate immunity system and the prospect of inflammatory markers serving as molecular targets for prevention and/or biomarkers for early risk prediction of T2DM. The potential of micronutrients replenishment to improve insulin action by attenuating inflammation is also evaluated in the context of the public health relevance of this approach.

Context: Inactivating mutations of the calcium-sensing receptor (CASR) are implicated in different hypercalcemic syndromes, including familial hypocalciuric hypercalcemia (FHH), primary hyperparathyroidism (PHPT), and familial isolated hyperparathyroidism (FIHP). However, molecular diagnostics applied to large nonselected hypercalcemic cohorts from a single center have not been reported. Objective: Our objective was to describe the prevalence, type, and potential pathogenicity of CASR mutations in a series of cases with FHH (n = 17), PHPT (n = 165), and FIHP (n = 3) and controls (n = 198) presenting at a single endocrine clinic. Subjects: All were prospectively evaluated at the “Casa Sollievo della Sofferenza” Hospital in southern Italy over a 3-yr period. Methods: CASR screening was conducted by denaturing HPLC. The variant CASRs were functionally characterized by transient transfection studies in kidney cells in vitro. Results: A single novel missense variant was identified in one PHPT case. However, in FHH probands, mutations were found in eight of 17 (47%). With a hypercalcemic family member, mutation detection rate in FHH rose to seven of eight (87%), whereas only one of nine sporadic cases was positive, and none of the three FIHP cases had detectable CASR mutations. Five missense variant CASRs, identified in control subjects, performed as wild type in functional assays, whereas the missense mutant CASRs identified in the FHH patients, and in the one PHPT case, exhibited significant impairment. A novel intronic mutation (IVS4-19a→c) found in one FHH family, created an abnormally spliced product in an in vitro minigene assay. Conclusion: CASR testing, with functional analysis, provides critical confirmatory evidence in the differential diagnosis of hypercalcemic states.

Summary Loci exhibiting Hardy-Weinberg disequilibrium (HWD) are often excluded from association studies, because HWD may indicate genotyping error, population stratification or selection bias. For case-control studies, HWD can result from a genetic effect at the locus. We extend the modelling to accommodate both stratification and genetic effects. Theoretical genotype frequencies and HWD coefficients are derived under a general genetic model for a population with two strata. Maximum likelihood is used to estimate model parameters and a test for lack of fit identifies the models most consistent with the data. Simulations were used to assess the method. The technique was applied to a group of ethnically and clinically heterogeneous kidney stone formers and controls, both exhibiting HWD for the R990G SNP of the CASR gene. Results indicate the best fitting model incorporates both stratification and genetic association. The ability of our method to apportion HWD to stratification and genetic effects may well be a significant advance in dealing with heterogeneity in case-control genetic association studies.

Background Serum magnesium concentration is a quantitative trait with substantial heritability. Although the pool of candidate genes continues to grow, only the histocompatibility locus has been associated with magnesium levels. To explore other possibilities, we targeted 6 candidate genes physiologically relevant to magnesium metabolism. Methods We studied a large cohort (n = 471) derived from a well-characterized population of healthy Caucasian women 18 to 35 years. Total serum magnesium and calcium were measured by atomic absorption spectrophotometry (aaMg & aaCa). Genomic DNA was amplified and SNPs in candidate genes (CASR, VDR, ESR1, CLDN16, EGF1, TRPM6) genotyped by routine methods. Results We found a significant association between estrogen receptor α (ESR1) polymorphisms, PvuII and XbaI, and magnesium (r = − 0.116, p = 0.012 and r = − 0.126, p = 0.006, respectively). Stratifying by PvuII genotype (P/p alleles), the mean adjusted total magnesium (aaMg) concentration was significantly higher (p = 0.01) in the pp group (0.823 ± 0.005 mmol/l, n = 130) than in PP homozygotes (0.805 ± 0.006 mmol/l, n = 70), and the mean in Pp heterozygotes was intermediate (0.810 ± 0.005 mmol/l, n = 180). No significant associations were observed with the other candidate genes tested. Conclusions The significant association between magnesium and ESR1 polymorphisms supports previous studies linking physiologic changes in serum magnesium to estrogen status.

Primary hyperparathyroidism (PHPT) is a common endocrine disease that is associated with multiple endocrine neoplasia type 1 (MEN1) in approximately 2% of PHPT cases. Lack of a family history and other specific expressions may lead to underestimated MEN1 prevalence in PHPT. The aim of this study was to identify clinical or biochemical features predictive of MEN1 and to compare the severity of the disease in MEN1-related versus sporadic PHPT (sPHPT). We performed a 36-mo cross-sectional observational study in three tertiary referral centers on an outpatient basis on 469 consecutive patients with sporadic PHPT and 64 with MEN1-related PHPT. Serum calcium, phosphate, PTH, 25(OH)D(3), and creatinine clearance were measured, and ultrasound examination of the urinary tract/urography was performed in all patients. In 432 patients, BMD was measured at the lumbar spine (LS) and femoral neck (FN). MEN1 patients showed lower BMD Z-scores at the LS (-1.33 +/- 1.23 versus -0.74 +/- 1.4, p = 0.008) and FN (-1.13 +/- 0.96 versus -0.6 +/- 1.07, p = 0.002) and lower phosphate (2.38 +/- 0.52 versus 2.56 +/- 0.45 mg/dl, p = 0.003) and PTH (113.8 +/- 69.5 versus 173.7 +/- 135 pg/ml, p = 0.001) levels than sPHPT patients. Considering probands only, the presence of MEN1 was more frequently associated with PTH values in the normal range (OR, 3.01; 95% CI, 1.07-8.50; p = 0.037) and younger age (OR, 1.61; 95% CI, 1.28-2.02; p = 0.0001). A combination of PTH values in the normal range plus age

Background To determine the effect of vitamin D binding protein (DBP) genotypes on 25-hydroxyvitamin D [25(OH)D] changes with vitamin D supplements, we studied 98 adults receiving 600 or 4000 IU/d vitamin D3 for one year. Methods The DBP functional variant, T436K, was genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Results Mean 25(OH)D increases were 97% for TT (n = 48), 151% for TK (n = 31) and 307% (n = 6) for KK genotypes (p = .004). Conclusions As with baseline 25(OH)D, T436K genotype predicts 25(OH)D changes after long-term vitamin D supplementation.

Summary Renal stone formation due to hypercalciuria is a relatively common disorder with clear evidence for genetic predisposition, but cryptic phenotypic heterogeneity has hampered identification of candidate genes. The R990G single-nucleotide polymorphism (SNP) of the calcium sensing receptor (CASR) gene has been associated with hypercalciuria in stone formers and shows the appropriate functional phenotype in cell culture. In our preliminary association analysis of a case-control cohort, however, we observed significant Hardy-Weinberg disequilibrium (HWD) for the cases (n= 223), but not controls (n= 676) at the R990G locus, pointing us toward the general disease model incorporating HWD. Because there is an adjacent CASR SNP, A986S, which is in negative linkage disequilibrium with R990G, we extended the general disease model to enable testing of a two-site hypothesis. In our data set, there is no lack of fit (P= .345) for the single-locus model for the R990G genotype, and likelihood ratio testing favors a recessive effect with an eight-fold increase in risk (P < .001) for GG homozygotes, relative to wild-type, based on a population prevalence of 2%. Addition of the A986S genotype provides no additional information either by itself or when included in our two-site model.

Although early epidemiologic studies showed a protective effect of adequate maternal folic acid (FA) status against neural tube defects (NTDs), the role of adequate vitamin B-12 nutrition in the putative reduction of NTD frequency has remained uncertain. Evaluating vitamin B-12 status was complicated by the need to control for altered FA status after fortification in Canada. More recent studies have made use of better biomarkers of vitamin B-12 status, including methylmalonic acid and holotranscobalamin (holoTC). HoloTC provides a useful measure of vitamin B-12 status because it represents the bioavailable fraction of circulating vitamin B-12. By assessing bioavailable vitamin B-12 status in a large Canadian cohort accrued before and after FA fortification, we found a 3-fold increase in the risk of NTDs in mothers who had vitamin B-12 status in the lower quartile, regardless of FA fortification. Our work suggests that vitamin B-12 fortification, analogous to the FA fortification program, may reduce NTDs more than FA fortification alone. A multicenter randomized controlled trial comparing periconceptional vitamin B-12 in combination with FA against FA alone is warranted.

The calcium-sensing receptor (CASR), a plasma membrane G-protein-coupled receptor, is expressed in parathyroid gland and kidney, and controls systemic calcium homeostasis. Inactivating CASR mutations are associated with familial hypocalciuric hypercalcemia (FHH) and neonatal severe hyperparathyroidism, and activating mutations cause autosomal dominant hypocalcemia (ADH). CASR mutation identification plays an important role in the clinical management of mineral metabolism disorders. We describe here a high-throughput method using screening with denaturing high performance liquid chromatography (DHPLC) to initially interrogate 12 amplicons covering translated exons and exon/intron boundaries, followed by sequencing of any amplicon with a modified melting curve relative to wild type, and direct sequencing of a 13th amplicon encoding the COOH-terminal tail to distinguish causative mutations from three common missense single nucleotide polymorphisms. A blinded analysis of 32 positive controls representing mutations throughout the CASR sequence, as well as 22 negative controls, yielded a concordance rate of 100%. We report eight novel and five recurrent FHH mutations, along with six novel and two recurrent ADH mutations. Thus, DHPLC provides a rapid and effective means to screen for CASR mutations.

Glial cells missing-2 (GCM2) is a transcription factor expressed in the parathyroid hormone (PTH)-secreting cells of the parathyroid gland and is essential for their development. Thus far, downstream targets of GCM2 have not been identified. Here, we show that both promoters (P1 and P2) of the calcium-sensing receptor (CASR) gene, a differentiation marker for the parathyroid gland, are transactivated by wild-type GCM2. GCM response elements within CASR P1 (-451 to -441; relative to the transcription start site at +1) and CASR P2 (-166 to -156) were identified by mutated promoter-reporter studies as well as oligonucleotide precipitation assays. Primary hypoparathyroidism is a heterogeneous group of conditions characterized by hypocalcemia and hyperphosphatemia due to deficient PTH secretion. A few cases of familial isolated hypoparathyroidism with autosomal recessive inheritance have been identified that are caused by homozygous inactivating mutations in the GCM2 gene. We describe the GCM2 mutations in two families with hypoparathyroidism, one inherited in an autosomal recessive fashion and the other in an autosomal dominant manner. In transfection studies using a promoter-reporter construct having synthetic multimerized GCM elements in the promoter, the dominantly inherited mutant GCM2 exerted a dominant-negative effect on wild-type GCM2 activity, whereas recessively inherited mutants did not. In addition, we show that the transactivation of the CASR promoter-reporter constructs by wild-type GCM2 is completely abolished in the presence of the dominant-negative mutant GCM2.

Replication is a critical step to validate positive genetic associations. In this study, we tested two previously reported positive associations. The low density lipoprotein receptor-related protein 5 (LRP5) Val667Met and lumbar spine bone density are replicated. This result is in line with results from large consortiums such as Genomos. However, the estrogen-related receptor alpha (ESRRA) repeat in the promoter is not replicated although the polymorphism studied was functional and could have been a causative variant. We sought to validate associations previously reported between LRP5 V667M polymorphism and lumbar spine (LS, p = 0.013) and femoral neck (FN, p = 0.0002) bone mineral density (BMD), and between ESRRA 23 base pair repeat polymorphism and LS BMD (p = 0.0036) in a sample of premenopausal Caucasian women using an independent sample. For the replication sample, we recruited 673 premenopausal women from the Toronto metropolitan area. All women were Caucasian and had BMD measured. LRP5 V667M was genotyped by allele-specific PCR and ESRRA repeats by sizing of PCR products on agarose gels. We reproduced the same association as we reported previously between LRP5 V667M and LS BMD (p = 0.015) but not with FN BMD (p = 0.254). The combined data from the two populations indicate an effect size of 0.28SD for LS BMD (p = 0.00048) and an effect size of 0.26 SD for FN BMD (p = 0.00037). In contrast, the association we reported earlier between ESRRA repeats and LS BMD was not replicated in the sample from Toronto (p = 0.645). The association between LRP5 V667M and LS BMD is confirmed but not that between ESRRA repeats and LS BMD. This result indicates that it is imperative to validate any positive association in an independent sample.

Summary We described the approximate variance for a composite measure of linkage disequilibrium (LD), which depends only on genotype frequencies and allows for departure from Hardy-Weinberg disequilibrium (Hamilton et al. 2006). Here we extend this work to allow for inferences about differences in composite LD coefficients, as we illustrate with two examples. Simulations demonstrate consistency of type I error rates under most conditions. Calculations for power and sample size are also given.

Objectives HLA-B*5701 strongly predicts abacavir hypersensitivity (HSR), but implementation of effective routine screening into clinical practice requires testing be practical and accurate. We tested the proficiency of HLA-B*5701 typing among laboratories using sequence-specific primer PCR. Design and methods DNA panels (1 and 2) were distributed to seven laboratories (A to G) for blinded typing of the HLA-B*5701 allele. Panel 1 ( n=10 samples; n=7 laboratories) included 3 positives and other closely related B17 subtypes (B*5702, B*5703, B*5704 and B*5801). Panel 2 ( n=96 samples; n=4 laboratories) included 36 positives among a broad spectrum of other B alleles. Two laboratories (A and B) also submitted 96 routine samples, typed by the same methodology, to the reference centre for additional analysis by sequence-based typing. Results All laboratories correctly typed panel 1 for HLA-B*5701 carriage. Laboratories A, B and C identified HLA-B*5701 alleles in panel 2 with 100% sensitivity and 100% specificity. Laboratory D reported one false negative, reportedly due to a sampling error. The results obtained for routine samples typed by laboratories A and B and those generated by the reference laboratory using sequencing were fully concordant. Conclusions Detection of HLA-B*5701 alleles among laboratories was 100% specific and 99.4% sensitive, indicating that participating HIV testing laboratories were currently offering effective primary screening to identify individuals at high risk of abacavir HSR. Accurate reporting of HLA-B*5701 status is critical for the safe administration of this drug and participation in quality assurance programmes by all sites who report HLA-B*5701 status should be promoted.

Objectives: The calcium-sensing receptor (CASR) is critical for maintenance of blood calcium in a narrow physiologic range. Naturally occurring mutations in the calcium-sensing receptor gene ( CASR ) cause hypocalcaemia or hypercalcaemia, and molecular diagnosis of these mutations is clinically important. Knowledge of SNP frequency and haplotype structure is essential in understanding molecular test results. Design and methods: Genotyping and haplotype analysis of 26 CASR SNPs (and a tetranucleotide insertion/deletion polymorphism) in control cohorts of Caucasian, Asian and African-American origin ( n = 1136, 88 and 104 chromosomes, respectively). Results: The three SNPs in exon 7 (A986S, R990G, Q1011E) are the only common exonic variants in our cohorts, and synonymous exonic SNPs are uncommon. Linkage disequilibrium analysis of the Caucasian cohort (Haploview) showed that the CASR locus is divided into three haplotype blocks, coincident with 5' regulatory, coding, and 3' regulatory domains. Conclusions: These analyses provide an important framework for appropriate interpretation of CASR mutation screening now offered by a number of laboratories for the diagnosis of calcium disorders. They will assist in the study of CASR polymorphisms as predictors of complex disease states.

Low maternal vitamin B(12) status may be a risk factor for neural tube defects (NTDs). Prior studies used relatively insensitive measures of B(12), did not adjust for folate levels, and were conducted in countries without folic acid food fortification. In Canada, flour has been fortified with folic acid since mid-1997.We completed a population-based case-control study in Ontario. We measured serum holotranscobalamin (holoTC), a sensitive indicator of B(12) status, at 15 to 20 weeks' gestation. There were 89 women with an NTD and 422 unaffected pregnant controls. A low serum holoTC was defined as less than 55.3 pmol/L, the bottom quartile value in the controls.The geometric mean serum holoTC levels were 67.8 pmol/L in cases and 81.2 pmol/L in controls. There was a trend of increasing risk with lower levels of holoTC, reaching an adjusted odds ratio of 2.9 (95% confidence interval = 1.2-6.9) when comparing the lowest versus highest quartile.There was almost a tripling in the risk for NTD in the presence of low maternal B(12) status, measured by holoTC. The benefits of adding synthetic B(12) to current recommendations for periconceptional folic acid tablet supplements or folic-acid-fortified foods need to be considered. It remains to be determined what fraction of NTD cases in a universally folate-fortified environment might be prevented by higher periconceptional intake of B(12).

Bisphosphonates are considered standard therapy in the treatment of patients with bone metastases from breast cancer. While bisphosphonate use has increased in recent years, it is important to appreciate that these agents are not a panacea. Some of the newer and more potent bisphosphonates are expensive, both in terms of drug acquisition costs and in terms of patient time, as they require frequent return visits to the clinic for intravenous therapy. Furthermore, the use of the potent intravenous bisphosphonates has been associated with serious toxicity, including renal dysfunction and osteonecrosis of the jaw. In many patients who receive these drugs, the course of their disease is not materially altered. Therefore, there is growing interest in the role of biochemical markers of bone turnover as predictors of which patients are going to derive the most palliative benefit from bisphosphonates. Of these markers, urinary N-telopeptide (uNTX) has been extensively investigated. This article reviews th...

Cysteinyl-leukotrienes (cysteinyl-LTs), that is, LTC4, LTD4, and LTE4, trigger contractile and inflammatory responses through the specific interaction with G protein-coupled receptors (GPCRs) belonging to the purine receptor cluster of the rhodopsin family, and identified as CysLT receptors (CysLTRs). Cysteinyl-LTs have a clear role in pathophysiological conditions such as asthma and allergic rhinitis (AR), and have been implicated in other inflammatory conditions including cardiovascular diseases, cancer, atopic dermatitis, and urticaria. Molecular cloning of human CysLT1R and CysLT2R subtypes has confirmed most of the previous pharmacological characterization and identified distinct expression patterns only partially overlapping. Interestingly, recent data provide evidence for the immunomodulation of CysLTR expression, the existence of additional receptor subtypes, and of an intracellular pool of CysLTRs that may have roles different from those of plasma membrane receptors. Furthermore, genetic variants have been identified for the CysLTRs that may interact to confer risk for atopy. Finally, a crosstalk between the cysteinyl-LT and the purine systems is being delineated. This review will summarize and attempt to integrate recent data derived from studies on the molecular pharmacology and pharmacogenetics of CysLTRs, and will consider the therapeutic opportunities arising from the new roles suggested for cysteinyl-LTs and their receptors. © 2006 Wiley Periodicals, Inc. Med Res Rev, 27, No. 4, 469–527, 2007

An autosomal recessive syndrome of hyperphosphatasia (elevated circulating alkaline phosphatase (AP), seizures and neurologic deficits) was first described by Mabry and colleagues in 1970. Over the ensuing four decades, few cases were reported. In 2010, however, new families were identified and the syndromic nature of the disorder confirmed. Shortly thereafter, next generation sequencing was used to characterize causative defects in the glycosyl phosphatidylinositol (GPI) biosynthetic pathway, based partly on our understanding of how AP is anchored by GPI to the plasma membrane. Whether the seizures and cognitive defects seen in Mabry syndrome patients are attributable in part to the constant hyperphosphatasia is not known, as there are more than 250 other proteins dependent on GPI for their anchoring to the plasma membrane. However, Mabry syndrome may provide a new window on AP function in growth and development.