Archival bone marrow samples: suitable for multiple biomarker analysis.

AB Archival samples represent a significant potential for genetic studies, particularly in severe diseases with risk of lethal outcome, such as in cancer. In this pilot study, we aimed to evaluate the usability of archival bone marrow smears and biopsies for DNA extraction and purification, whole genome amplification (WGA), multiple marker analysis including 10 short tandem repeats, and finally a comprehensive genotyping of 33,683 single nucleotide polymorphisms (SNPs) with multiplexed targeted next-generation sequencing. A total of 73 samples from 21 bone marrow smears and 13 bone marrow biopsies from 18 Danish and Norwegian childhood acute lymphoblastic leukemia patients were included and compared with corresponding blood samples. Samples were grouped according to the age of sample and whether WGA was performed or not. We found that measurements of DNA concentration after DNA extraction was dependent on detection method and that spectrophotometry overestimated DNA amount compared with fluorometry. In the short tandem repeat analysis, detection rate dropped slightly with longer fragments. After WGA, this drop was more pronounced. Samples stored for 0 to 3 years showed better results compared with samples stored for 4 to 10 years. Acceptable call rates for SNPs were detected for 7 of 42 archival samples. In conclusion, archival bone marrow samples are suitable for DNA extraction and multiple marker analysis, but WGA was less successful, especially when longer fragments were analyzed. Multiple SNP analysis seems feasible, but the method has to be further optimized.

Host genome variations and risk of infections during induction treatment for childhood acute lymphoblastic leukaemia.

OBJECTIVES: To investigate association of host genomic variation and risk of infections during treatment for childhood acute lymphoblastic leukaemia (ALL). METHODS: We explored association of 34,000 single-nucleotide polymorphisms (SNPs) related primarily to pharmacogenomics and immune function to risk of infections among 69 ALL patients on induction therapy. RESULTS: Forty-eight (70%) patients experienced infectious events including 23 with positive blood cultures. Infectious events and positive blood cultures were associated significantly with 24 and 21 SNPs, respectively (P < 0.01). Classification and regression tree analysis demonstrated rs11033797 (OR51F1), rs2835265 (CBR1), rs28627172 (POLDIP3) and rs1129844 (CCL11) to be predictive of outcome. Among 61 patients for whom read-outs were available for all four SNPs, 40 of 41 patients with the worst SNP profile experienced at least one infectious event compared with five of the remaining 20 patients (Hazard ratio 9.0, 95% CI 3.4-23.5, which was unchanged after adjustments for neutrophil counts). Pathway analysis identified variations in 'G-protein-coupled receptor (GPCR) downstream signalling', 'Bile acid and bile salt metabolism' and 'Class I MHC-mediated antigen processing and presentation' to be highly predictive of infections. CONCLUSIONS: Our data indicate that host genomic profiling may predict the risk of infections during induction therapy. This may facilitate development of individualised supportive care.

Serological screening for celiac disease in schoolchildren in Jordan. Is height and weight affected when seropositive?

BACKGROUND: Celiac disease (CD) emerged as a public health problem, and the disease prevalence varies among different races. The present study was designed to investigate the prevalence of CD using serological markers in apparently healthy schoolchildren in Irbid City, Jordan. Additionally, the effect of positive serology on height, weight and body mass index (BMI) was evaluated. METHODS: The study population consisted of 1985 children (1117 girls and 868 boys), age range was 5.5 to 9.5 years. Height and weight were measured and blood samples were collected from each individual. Serum samples were analyzed for IgA anti-tissue transglutaminase antibodies (tTG) using a commercial enzyme-linked immunosorbent assay (ELISA). tTG positive samples were further analyzed for IgA anti-endomysium antibodies (EmA) with a commercial ELISA. Samples confirmed positive with EmA were considered seropositive. RESULTS: Sixteen children were CD positive. The serological prevalence was estimated to be 1:124 (0.8%; 95% CI, 0.5% to 1.3%). Significant impact on growth (height) was found in seropositive children. When both sexes were individually analyzed, only boys showed height reduction. Furthermore, seropositive boys also had a significant weight reduction. CONCLUSION: This study demonstrated that CD is prevalent among schoolchildren in Jordan. The seropositive children tend to have lower height, weight, and BMI than the seronegative group. These differences were significant only for boys. None of the participants is known to have CD prior to the study.

Significance of the parkin and PINK1 gene in Jordanian families with incidences of young-onset and juvenile parkinsonism.

BACKGROUND: Parkinson's disease is a progressive neurodegenerative disorder, where most cases are sporadic with a late onset. In rare incidences familial forms of early-onset parkinsonism occur, and when recessively inherited, cases are often explained by mutations in either the parkin (PARK2) or PINK1 (PARK6) gene or on exceptional occasions the DJ-1 (PARK7) or ATP13A2 (PARK9) gene. Recessively inherited deletions/duplications and point mutations in the parkin gene are the most common cause of early-onset parkinsonism known so far, but in an increasing number of studies, genetic variations in the serine/threonine kinase domain of the PINK1 gene are found to explain early-onset parkinsonism. METHODS: In this study all families were from a population with a high incidence of consanguinity. We investigated 11 consanguineous families comprising 17 affected with recessively inherited young-onset parkinsonism for mutations both in the parkin and PINK1 gene. Exons and flanking regions were sequenced, and segregation patterns of genetic variation were assessed in members of the respective families. An exon dosage analysis was performed for all exons in both genes. RESULTS: In the parkin gene, a three generation family was identified with an exon 4 deletion segregating with disease. Both affected were homozygous for the deletion that segregated on a haplotype that spanned the gene in a haplotype segregation analysis that was performed using additional markers. Exon dosage analysis confirmed the recessive pattern of inheritance with heterozygous deletions segregating in healthy family members. In the PINK1 gene we identified two novel putative pathogenic substitutions, P416R and S419P, located in a conserved motif of the serine/threonine kinase domain. Both substitutions segregated with disease in agreement with a recessive pattern of inheritance within respective families and both were present as homozygous in two affected each. We also discuss common polymorphisms in the two genes found to be co-segregating within families. CONCLUSION: Our results further extend on the involvement of PINK1 mutations in recessive early-onset parkinsonism with clinical features similar to carriers of parkin mutations.

The HLA-G 14bp gene polymorphism and decidual HLA-G 14bp gene expression in pre-eclamptic and normal pregnancies.

Trophoblast expression of the non-classical MHC, HLA-G, is considered essential for feto-maternal immune tolerance and successful placentation in pregnancy. The HLA-G 14bp polymorphism in the 3'-untranslated region (UTR) of the HLA-G gene has been reported to be associated with development of pre-eclampsia (PE). In this study, maternal (peripheral blood, n=54) and fetal (cord blood, n=57) HLA-G 14bp genotypes have been determined by PCR in pre-eclamptic and normal pregnancies. In addition, HLA-G 14bp gene expression in decidua basalis (n=59) was analyzed by RT-PCR. The pre-eclamptic syndrome was neither associated with the HLA-G 14bp genotype (maternal or fetal), nor with altered decidual HLA-G 14bp gene expression. Furthermore, the HLA-G 14bp mRNA expressed in decidua basalis was of fetal origin and all potential transcripts, as predicted from the fetal HLA-G 14bp genotype, were expressed. In contrast to previous findings, we found no correlation between the HLA-G 14bp polymorphism and fetal growth. In conclusion, the fetal HLA-G 14bp genotype is reflected in the decidual HLA-G mRNA splice form profile, but does not appear to be associated with increased risk for development of PE.

Genetic association study of synphilin-1 in idiopathic Parkinson's disease.

BACKGROUND: Post-mortem Lewy body and Lewy neuritic inclusions are a defining feature of Parkinson's disease (PD) and dementia with Lewy bodies (DLB). With the discovery of missense and multiplication mutations in the alpha-synuclein gene (SNCA) in familial parkinsonism, Lewy inclusions were found to stain intensely with antibodies raised against the protein. Yeast-two-hybrid studies identified synphilin-1 as an interacting partner of alpha-synuclein, and both proteins show co-immunolocalization in a subset of Lewy body inclusions. In the present study, we have investigated whether common variability in synphilin-1, including coding substitutions are genetically associated with disease pathogenesis. METHODS: We screened the synphilin-1 gene for 11 single nucleotide polymorphisms (SNPs) in 300 affected subjects with idiopathic Parkinson's disease and 412 healthy controls. Six of these were rare variants including five previously identified amino acid substitutions that were chosen in a direct approach for association of rare disease causing mutations. An additional five highly heterozygous SNPs were chosen for an indirect association approach including haplotype analysis, based on the assumption that any disease causing mutations might be in linkage disequilibrium with the SNPs selected. We also genotyped a microsatellite marker (D5S2950) within intron 6 of the gene and five additional microsatellites clustered downstream of the 5p23.1-23.3 synphilin-1 locus. Genome-wide linkage analysis, in a number of independent studies, has previously highlighted suggestive linkage to PD in this region of chromosome 5. RESULTS: Screening of previously known amino acid substitutions in the synphilin-1 gene, identified the C1861>T (R621C) substitution in four patients (chromosomes n = 600) and 10 control subjects (chromosomes n = 824), whereas the G2125>C (E706Q) substitution was detected in one patient and four control subject, suggesting both these substitutions are not associated with susceptibility to PD. Heterozygous non-synonymous T131>C (V44A) and synonymous C636>T (P212P) amino acid substitutions were each detected in only one patient with PD. Heterozygous C1134>T (L378L) synonymous substitutions were found in two patients with PD and one control subject. D5S2010 the most distal telomeric microsatellite marker genotyped,15.3 Mb from synphilin-1, was genetically associated with PD (p = 0.006, 27df) independently adjusted for multiple testing according to its high amount of alleles but not the total number of other markers investigated. Other flanking and intronic SNP and microsatellite markers showed no evidence for genetic association with disease. CONCLUSION: In this study rare synphilin-1 SNPs were assessed in a direct association approach to identify amino acid substitutions that might confer risk of PD in a homozygous or compound heterozygous state. We found none of these rare variations were associated with disease. In contrast to prior studies the frequency of the R621C substitution was not significantly different between PD and control subjects, neither were the V44A or E706Q substitutions. Similarly, our indirect study of more heterozygous SNPs, including both single marker and haplotype analyses, showed no significant association to PD. However, marginal association of microsatellite alleles with idiopathic PD, within the chromosome 5q21 region, indicates further studies are warranted.

Altered expression of PGK1 in a family with phosphoglycerate kinase deficiency.

The X-linked recessive disease phosphoglycerate kinase (PGK) deficiency is caused by altered expression of the PGK1 enzyme, which causes muscle stiffness, hemolytic anemia, and mental retardation. In this study we characterized the PGK1 gene in a family of two brothers, two sisters, and their parents. A single mutation in exon 6, which was associated with the pattern of inheritance of PGK1 deficiency, was observed. This silent G213G; c.639C>T mutation was localized to the conserved exon-intron boundary. We have developed a method for quantification of PGK1 mRNA and demonstrated a marked reduction in PGK1 mRNA in both brothers with the disease. A smaller decrease in PGK1 expression was observed in one sister with symptoms of PGK deficiency and in her mother. Only the normal PGK1 allele was expressed in the two heterozygous women. Whereas most known PGK1 mutations cause amino acid alterations, our study indicates that inhibition of the transcription mechanism is the cause of PGK deficiency.

Two cysteine substitutions in the MC1R generate the blue variant of the Arctic fox (Alopex lagopus) and prevent expression of the white winter coat.

We have characterized two mutations in the MC1R gene of the blue variant of the arctic fox (Alopex lagopus) that both incorporate a novel cysteine residue into the receptor. A family study in farmed arctic foxes verified that the dominant expression of the blue color phenotype cosegregates completely with the allele harboring these two mutations. Additionally to the altered pigment synthesis, the blue fox allele suppresses the seasonal change in coat color found in the native arctic fox. Consequently, these findings suggest that the MC1R/agouti regulatory system is involved in the seasonal changes of coat color found in arctic fox.

Mapping and characterization of the dominant black colour locus in sheep.

Dominant black pigment synthesis in sheep is caused by alterations of the melanocortin-1 receptor (MC1-R) coding sequence. Using five bovine microsatellite markers we have mapped the sheep MC1-R gene to chromosome 14, corresponding to the location in other mammalian species. The existence of two independent mutations, both causing an amino acid substitution, in distantly related breeds of sheep, support the hypothesis that the observed black pigment synthesis is caused by a mutual effect of the two mutations. As similar mutations are found separately at both locations in dominant black variants of other animal species, it is also possible that any of the two mutations could be sufficient for a partial pigment switch.

The use of genetic markers to measure genomic response to selection in livestock.

A method to measure genomic response to natural and artificial selection by means of genetic markers in livestock is proposed. Genomic response through several levels of selection was measured using sequential testing for distorted segregation of alleles among selected and nonselected sons, single-sperm typing, and a test with records for growth performance. Statistical power at a significance level of 0.05 was >0.5 for a marker linked to a QTL with recombination fractions 0, 0.10, and 0.20 for detecting genomic responses for gene effects of 0.6, 0.7, and 1.0 phenotypic standard deviations, respectively. Genomic response to artificial selection in six commercial bull sire families comprising 285 half-sib sons selected for growth performance was measured using 282 genetic markers evenly distributed over the cattle genome. A genome-wide test using selected sons was significant (P < 0.001), indicating that selection induces changes in the genetic makeup of commercial cattle populations. Markers located in chromosomes 6, 10, and 16 identified regions in those chromosomes that are changing due to artificial selection as revealed by the association of records of performance with alleles at specific markers. Either natural selection or genetic drift may cause the observed genomic response for markers in chromosomes 1, 7, and 17.