Karla J. Matteson

Maternal antibrain antibodies in autism

Autism is a neurodevelopmental disorder of prenatal onset that is behaviorally defined. There is increasing evidence for systemic and neuroimmune mechanisms in children with autism. Although genetic factors are important, atypical prenatal maternal immune responses may also be linked to the pathogenesis of autism. We tested serum reactivity in 11 mothers and their autistic children, maternal controls, and several groups of control children, to prenatal, postnatal, and adult rat brain proteins, by immunoblotting. Similar patterns of reactivity to prenatal (gestational day 18), but not postnatal (day 8) or adult rat brain proteins were identified in autistic children, their mothers, and children with other neurodevelopmental disorders, and differed from mothers of normal children, normal siblings of children with autism and normal child controls. Specific patterns of antibody reactivity were present in sera from the autism mothers, from 2 to 18 years after the birth of their affected children and were unrelated to birth order. Immunoblotting using specific antigens for myelin basic protein (MBP) and glial acidic fibrillary protein (GFAP) suggests that these proteins were not targets of the maternal antibodies. The identification of specific serum antibodies in mothers of children with autism that recognize prenatally expressed brain antigens suggests that these autoantibodies could cross the placenta and alter fetal brain development.

A silica-based mitochondrial DNA extraction method applied to forensic hair shafts and teeth.

The purpose of this study is to evaluate the applicability of a nonorganic DNA extraction method for use in the analysis of environmentally compromised forensic hair shaft and tooth samples. The condition of the samples included cases of water decomposition, severe incineration, and varying stages of putrefaction. Enzymatic amplification and manual sequencing of the first segment of the mitochondrial hypervariable region were performed successfully on each of the 20 autopsied individuals. The results indicate that the silica-based extraction method produces mtDNA suitable for genetic identification from forensic samples including hair shafts and teeth.

Establishment of Stably EBV-Transformed Cell Lines from Residual Clinical Blood Samples for Use in Performance Evaluation and Quality Assurance in Molecular Genetic Testing

Positive control materials for clinical molecular genetic testing applications are currently in critically short supply or non-existent for many genetically based diseases of public health importance. Here we demonstrate that anonymous, residual, clinical blood samples are potential sources of viable lymphocytes for establishing Epstein-Barr virus (EBV)-transformed blood lymphocyte cell lines. We attempted to transform 34 residual blood samples, and analyzed transformation success with respect to sample age, anticoagulant, storage temperature, volume, hemolysis, and patient age and sex. In univariate analysis, sample age was significantly associated with transformation success (P = 0.002). The success rate was 67% (6 of 9) for samples 1 to 7 days old, 38% (3 of 8) for samples 8 to 14 days old and 0% for samples 15 to 21 (0 of 11) days old. When we controlled for sample age in multivariate logistic regression, anticoagulant and storage temperature approached significance (P = 0.070 and 0.087, respectively; samples in acid citrate dextrose (ACD) and refrigerated samples were more likely to transform). Based on these findings, we suggest that samples collected in either ACD or ethylene diamine tetraacetic acid, and up to 14 days old (refrigerated) or 7 days old (stored ambient), are reasonable candidates for EBV transformation. The transformation rate for samples that met these criteria was 63% (10 of 16). Implementation of this process could help alleviate the shortage of positive control materials for clinical molecular genetic testing.

Effects of processing techniques on the forensic DNA analysis of human skeletal remains

Human remains processed by forensic anthropologists may potentially be used for genetic analysis. Therefore, the condition of the deoxyribonucleic acid (DNA) in processed remains may become an issue for future analysis. Processing techniques employed by anthropologists are highly variable and scanning electron microscopy reveals significant alterations to the bone surface depending upon the technique used. Such damage to the bone indicates differences may exist in quality and quantity of DNA extracted. This study assessed how five processing procedures used by major forensic anthropology laboratories around the country affects the amounts of DNA extracted from human rib bones and the subsequent DNA analysis. The DNA was analyzed using the short tandem repeat (STR) locus CSF1PO and amelogenin. The findings indicate processing procedures used by forensic anthropologists do not adversely affect DNA analysis but prolonged exposure to heat during processing may decrease the yield of information from the DNA.

Comparison of clonal relatedness and antimicrobial susceptibility of fecal Escherichia coli from healthy dogs and their owners

OBJECTIVE To determine prevalence of within-household sharing of fecal Escherichia coli between dogs and their owners on the basis of pulsed-field gel electrophoresis (PFGE), compare antimicrobial susceptibility between isolates from dogs and their owners, and evaluate epidemiologic features of cross-species sharing by use of a questionnaire. SAMPLE POPULATION 61 healthy dog-owner pairs and 30 healthy control humans. PROCEDURES 3 fecal E coli colonies were isolated from each participant; PFGE profiles were used to establish relatedness among bacterial isolates. Susceptibility to 17 antimicrobials was determined via disk diffusion. A questionnaire was used to evaluate signalment, previous antimicrobial therapy, hygiene, and relationship with dog. RESULTS A wide array of PFGE profiles was observed in E coli isolates from all participants. Within-household sharing occurred with 9.8% prevalence, and across-household sharing occurred with 0.3% prevalence. No behaviors were associated with increased clonal sharing between dog and owner. No differences were found in susceptibility results between dog-owner pairs. Control isolates were more likely than canine isolates to be resistant to ampicillin and trimethoprim-sulfamethoxazole. Owners and control humans carried more multdrug-resistant E coli than did dogs. CONCLUSIONS AND CLINICAL RELEVANCE Within-household sharing of E coli was detected more commonly than across-household sharing, but both direct contact and environmental reservoirs may be routes of cross-species sharing of bacteria and genes for resistance. Cross-species bacterial sharing is a potential public health concern, and good hygiene is recommended.

Development of genomic reference materials for Huntington disease genetic testing

Purpose: Diagnostic and predictive testing for Huntington disease requires an accurate measurement of CAG repeats in the HD (IT15) gene. However, precise repeat sizing can be technically challenging, and is complicated by the lack of quality control and reference materials (RM). The aim of this study was to characterize genomic DNA from 14 Huntington cell lines available from the National Institute of General Medical Sciences Human Genetic Cell Repository at the Coriell Cell Repositories for use as reference materials for CAG repeat sizing.Methods: Fourteen Huntington cell lines were selected for study. The alleles in these materials represent a large range of sizes that include important diagnostic cutoffs and allele combinations. The allele measurement study was conducted by ten volunteer laboratories using a variety of polymerase chain reaction-based in-house developed methods and by DNA sequence analysis.Results: The Huntington alleles in the 14 genomic DNA samples range in size from 15 to 100 CAG repeats. There was good agreement among the ten laboratories, and thus, the 95% confidence interval was small for each measurement. The allele size determined by DNA sequence analysis agreed with the laboratory developed tests.Conclusion: These DNA materials, which are available from Coriell Cell Repositories, will facilitate accurate and reliable Huntington genetic testing.

Use of a molecular genetic approach to diagnosing the fragile X genotype

We report the direct molecular detection of the fragile X genotype in 111 individuals from 17 families with a total of 31 cases of fragile X syndrome. Comparison of our molecular data with our previous cytogenetic and linkage data from these same families indicates the effectiveness of the direct molecular analysis. We have been able to assign a genotype unambiguously in 100% of the persons tested, and in all cases the molecular data correlated with the cytogenetic or linkage findings or both. Two of the three families presented in this study represent inheritance of this gene through normal transmitting males, and the third is strongly suggestive of this mode of inheritance. Our data show that the direct molecular approach will be of great utility for confirmation of the diagnosis and for the detection of female carriers and normal transmitting males who are at high risk for having affected children or grandchildren.