Fragile X Syndrome: Scientific Background and Screening Technologies.

Fragile X is the most common inherited cause of mental retardation with a prevalence of 1 in 4000 for males and 1 in 5000 to 8000 for females. The American College of Medical Genetics and Genomics has recommended diagnostic testing for fragile X in symptomatic persons, women with ovarian dysfunction, and persons with tremor/ataxia syndrome. Although medical and scientific professionals do not currently recommend screening nonsymptomatic populations, improvements in current treatment approaches and ongoing clinical trials have generated growing interest in screening for fragile X.

Detection of Antibodies Directed to the N-Terminal Region of GAD Is Dependent on Assay Format and Contributes to Differences in the Specificity of GAD Autoantibody Assays for Type 1 Diabetes.

GAD autoantibodies (GADAs) are sensitive markers of islet autoimmunity and type 1 diabetes. They form the basis of robust prediction models and are widely used for the recruitment of subjects at high risk of type 1 diabetes to prevention trials. However, GADAs are also found in many individuals at low risk of diabetes progression.

Novel method to characterize CYP21A2 in Florida patients with congenital adrenal hyperplasia and commercially available cell lines.

Congenital adrenal hyperplasia (CAH) is an autosomal recessive disorder and affects approximately 1 in 15,000 births in the United States. CAH is one of the disorders included on the Newborn Screening (NBS) Recommended Uniform Screening Panel. The commonly used immunological NBS test is associated with a high false positive rate and there is interest in developing second-tier assays to increase screening specificity.

Serum proteomics reveals systemic dysregulation of innate immunity in type 1 diabetes.

Using global liquid chromatography-mass spectrometry (LC-MS)-based proteomics analyses, we identified 24 serum proteins that were significantly variant between those with type 1 diabetes (T1D) and healthy controls. Functionally, these proteins represent innate immune responses, the activation cascade of complement, inflammatory responses, and blood coagulation. Targeted verification analyses were performed on 52 surrogate peptides representing these proteins, with serum samples from an antibody standardization program cohort of 100 healthy control and 50 type 1 diabetic subjects.

Diabetes antibody standardization program: first proficiency evaluation of assays for autoantibodies to zinc transporter 8.

Background: Zinc transporter 8 (ZnT8) is a recently identified major autoantigen in type 1 diabetes, and autoantibodies to ZnT8 (ZnT8A) are new markers for disease prediction and diagnosis. Here we report the results of the first international proficiency evaluation of ZnT8A assays by the Diabetes Antibody Standardization Program (DASP).

Methods: After a pilot workshop in 2007, an expanded ZnT8A workshop was held in 2009, with 26 participating laboratories from 13 countries submitting results of 63 different assays.

Diabetes Antibody Standardization Program: First evaluation of assays for autoantibodies to IA-2β.

Objective: Autoantibodies to IA-2β (IA-2βA) are important risk markers of type 1 diabetes. We report the first Diabetes Antibody Standardization Program (DASP) evaluation of IA-2βA assays.

Research Design And Methods: Thirteen laboratories from nine countries received coded sera from 50 patients with newly diagnosed type 1 diabetes and 100 healthy blood donors.

Perturbations in the lipid profile of individuals with newly diagnosed type 1 diabetes mellitus: lipidomics analysis of a Diabetes Antibody Standardization Program sample subset.

Objectives: To characterize the lipid profile of individuals with newly diagnosed type 1 diabetes mellitus using LC-MS-based lipidomics and the accurate mass and time (AMT) tag approach.

Design And Methods: Lipids were extracted from plasma and sera of 10 subjects from the Diabetes Antibody Standardization Program (years 2000-2005) and 10 non-diabetic subjects and analyzed by capillary liquid chromatography coupled with a hybrid ion-trap-Fourier transform ion cyclotron resonance mass spectrometer. Lipids were identified and quantified using the AMT tag approach.

Harmonization of glutamic acid decarboxylase and islet antigen-2 autoantibody assays for national institute of diabetes and digestive and kidney diseases consortia.

Background/rationale: Autoantibodies to islet antigen-2 (IA-2A) and glutamic acid decarboxylase (GADA) are markers for diagnosis, screening, and measuring outcomes in National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) consortia studies. A harmonization program was established to increase comparability of results within and among these studies.

Methods: Large volumes of six working calibrators were prepared from pooled sera with GADA 4.

Genetic variants associated with fasting blood lipids in the U.S. population: Third National Health and Nutrition Examination Survey.

Background: The identification of genetic variants related to blood lipid levels within a large, population-based and nationally representative study might lead to a better understanding of the genetic contribution to serum lipid levels in the major race/ethnic groups in the U.S. population.

Technologies for diabetes genomics.

The genetic risk for diabetes largely depends on the type of diabetes and the penetrance and severity of the effect of the contributing genes. This ranges from the high-risk mutations of neonatal diabetes and maturityonset diabetes of the young to the lower, but still significant, risk conferred by common human leukocyte antigen alleles in type 1 diabetes to the still-lower risk conferred by the common variants associated with type 2 diabetes. There are many new molecular technologies, each with their own set of methodological issues, that have been used for genome-wide association studies and that can be used for determining the genetic risk for these various types of diabetes.

Novel human leukocyte antigen class I and class II alleles identified by sequence-based typing in the Genetics of Kidneys in Diabetes (GoKinD) study population.

Nine novel HLA class I and class II alleles were identified by sequence-based typing (SBT) in Caucasian participants from the Genetics of Kidneys in Diabetes (GoKinD) study. All novel alleles were single nucleotide substitutions. Seven alleles resulted in an amino acid change and two alleles were silent substitutions.

Assessment of DNA contamination from dried blood spots and determination of DNA yield and function using archival newborn dried blood spots.

Background: Residual dried blood spots (DBS) from newborn screening programs are often stored for years and are sometimes used for epidemiological studies. Because there is potential for DNA cross-contamination from specimen-to-specimen contact, we determined contamination levels following intentional contact and assessed archival DBS DNA degradation after storage in an uncontrolled environment.

Methods: DBS from healthy adult females were rubbed with DBS from healthy or cystic fibrosis (CF)-affected adult males.

Sequence variants in the PLEKHH2 region are associated with diabetic nephropathy in the GoKinD study population.

Nephropathy is a common microvascular complication of diabetes with a genetic component for disease development. Genetic analyses have implicated multiple chromosomal regions for disease susceptibility but no single locus can account for the majority of the genetic component. Here, we report a genetic analysis of the PLEKHH2 gene that was identified through a single nucleotide polymorphism (SNP) genome-wide association study (GWAS) for association with the development of diabetic nephropathy (DN) in the Genetics of Kidneys in Diabetes (GoKinD) study population.

Application of proteomics in the discovery of candidate protein biomarkers in a diabetes autoantibody standardization program sample subset.

Novel biomarkers of type 1 diabetes must be identified and validated in initial, exploratory studies before they can be assessed in proficiency evaluations. Currently, untargeted "-omics" approaches are underutilized in profiling studies of clinical samples. This report describes the evaluation of capillary liquid chromatography (LC) coupled with mass spectrometry (MS) in a pilot proteomic analysis of human plasma and serum from a subset of control and type 1 diabetic individuals enrolled in the Diabetes Autoantibody Standardization Program, with the goal of identifying candidate biomarkers of type 1 diabetes.

Nephropathy in type 1 diabetes is diminished in carriers of HLA-DRB1*04: the genetics of kidneys in diabetes (GoKinD) study.

Objective: The purpose of this study was to examine whether known genetic risk factors for type 1 diabetes (HLA-DRB1, -DQA1, and -DQB1 and insulin locus) play a role in the etiology of diabetic nephropathy. RESEARCH DESIGN AND METHODS; Genetic analysis of HLA-DRB1, -DQA1, -DQB1 and the insulin gene (INS) was performed in the Genetics of Kidneys in Diabetes (GoKinD) collection of DNA (European ancestry subset), which includes case patients with type 1 diabetes and nephropathy (n = 829) and control patients with type 1 diabetes but not nephropathy (n = 904). The availability of phenotypic and genotypic data on GoKinD participants allowed a detailed analysis of the association of these genes with diabetic nephropathy.

Combined testing of antibody titer and affinity improves insulin autoantibody measurement: Diabetes Antibody Standardization Program.

The aim of the workshop was to assess whether four laboratories could reproducibly measure insulin autoantibody (IAA) affinity in coded sera from non-diabetic relatives of patients with type 1 diabetes, newly diagnosed patients, and healthy blood donors, and whether combining affinity with autoantibody titer could improve concordance and performance of IAA assays. IAA affinity was measured by competitive binding using constant amounts of Tyr14A [125I] human insulin and increasing quantities of unlabeled human insulin. There was high concordance between laboratories in distinguishing high, moderate, and low affinity IAA, although IAA binding to insulin varied with assay format.

Genetics of Kidneys in Diabetes (GoKinD) study: a genetics collection available for identifying genetic susceptibility factors for diabetic nephropathy in type 1 diabetes.

The Genetics of Kidneys in Diabetes (GoKinD) study is an initiative that aims to identify genes that are involved in diabetic nephropathy. A large number of individuals with type 1 diabetes were screened to identify two subsets, one with clear-cut kidney disease and another with normal renal status despite long-term diabetes. Those who met additional entry criteria and consented to participate were enrolled.

Identification of two novel DQA1 alleles, DQA1*0107 and DQA1*0602, by sequence-based typing in the GoKinD population.

Two novel DQA1 alleles, DQA1*0107 and DQA1*0602, were discovered using DQA1 sequence-based typing (SBT) in participants in the Genetics of Kidneys in Diabetes (GoKinD) Study. The DQA1*0107 allele, found in three unrelated Caucasian participants, contains a novel polymorphism at codon 79 of exon 2 (CGC-->TGC), which results in an amino acid change from an arginine to a cysteine. The participants containing this novel polymorphism also had a 1-bp insertion in intron 2 that is common to the *01 alleles.

Polymorphism scan for differences between transmitted and nontransmitted DRB1*030101 alleles outside of exon 2 for type 1 diabetes: the frequency of polymorphisms is similar.

DRB1*030101 is a major genetic risk factor for type 1 diabetes mellitus (T1DM) and is the only DRB1*03 allele usually seen in T1DM probands. Approximately 16% of parental DRB1*030101 alleles were not transmitted to T1DM probands in our Genetics of Kidneys and Diabetes study trio families. We performed a polymorphism screen to determine whether variations exist in DRB1*030101 alleles outside of exon 2 that may modify risk for developing T1DM.

Diabetes Antibody Standardization Program: first assay proficiency evaluation.

The aims of the first proficiency evaluation of the Diabetes Antibody Standardization Program (DASP) were to assess general implementation of assay methods and to evaluate the new World Health Organization (WHO) reference reagent for autoantibodies to GAD and IA-2. Forty-six laboratories in 13 countries received coded sera from 50 patients with newly diagnosed type 1 diabetes and 50 blood donor control subjects, together with the WHO reference reagent and diluent serum. Results were analyzed using receiver operator characteristic (ROC) curves.

Homocyst(e)ine and cardiovascular disease: a systematic review of the evidence with special emphasis on case-control studies and nested case-control studies.

Background: Elevated concentrations of homocyst(e)ine are thought to increase the risk of vascular diseases including coronary heart disease and cerebrovascular disease.

Methods: We searched MEDLINE (1966-1999), EMBASE (1974-1999), SciSearch (1974- 1999), and Dissertation Abstracts (1999) for articles and theses about homocyst(e)ine concentration and coronary heart disease and cerebrovascular disease.

Results: We included 57 publications (3 cohort studies, 12 nested case-control studies, 42 case-control studies) that reported results on 5518 people with coronary heart disease (11,068 control subjects) and 1817 people with cerebrovascular disease (4787 control subjects) in our analysis.

Effects of exposure to low levels of environmental cadmium on renal biomarkers.

We conducted a study among residents of a small community contaminated with heavy metals from a defunct zinc smelter and residents from a comparison community to determine whether biologic measures of cadmium exposure were associated with biomarkers of early kidney damage. Creatinine-adjusted urinary cadmium levels did not differ between the smelter and comparison communities; thus we combined individuals from both communities (n = 361) for further analyses. The overall mean urinary cadmium level was low, 0.