Exome sequencing reveals three homozygous missense variants in SNRPA in two sisters with syndromic intellectual disability.

Splicing-related gene mutations might affect the expression of a single gene or multiple genes and cause clinically heterogeneous diseases. With the advent of next-generation sequencing, several splicing gene mutations have been exposed, yet most major spliceosome genes have no reports of germline mutations and therefore, their effects are largely unknown. We describe the previously unreported concurrence of intellectual disability, short stature, poor speech, and minor craniofacial and hand anomalies in 2 female siblings with 3 homozygous missense variants in SNRPA (a component of the U1 small nuclear ribonucleoprotein complex) characterized by homozygosity mapping and whole exome sequencing. Combined, c.97A>G, c.98T>C, and c.100T>A, in exon 2 of SNRPA lead to p.Ile33Ala and p.Phe34Ile exchanges, which were predicted in silico to be deleterious. Although both patients exhibited some clinical features seen in other spliceosomal disorders, their complete clinical phenotype appears to be rather uncommon, a finding that may further support the notion that mutations in components of the major spliceosome do not strictly lead to the same syndromes/phenotypes.

Genetic contribution of CYP2C9, CYP2C19, and APOE variants in acenocoumarol response.

Oral anticoagulants of the coumarin type have an inconveniently narrow therapeutic window, making their use difficult. In Mexico, genetic variables that participate in the heterogeneity of the therapeutic response remain poorly investigated. With the focus on warfarin, extensive pharmacogenomic studies have been performed, including those on the CYP450 family and APOE. The objective of this study was to determine the contribution of CYP2C9, CYP2C19, and APOE polymorphisms to the variations in response to the doses of acenocoumarol, which is the main anticoagulant prescribed to the Mexican population. The polymerase chain reaction-restriction fragment length polymorphism method was applied to identify 2 and 3 of CYP2C9, 2 of CYP2C19, and APOE variants. The genetic distribution of every polymorphism tested showed high variability when compared with other populations worldwide. Our results showed statistical differences only in the CYP2C19 gene between the 1 1 and 1 2 groups, with effective acenocoumarol doses of 2.56 ± 1.34 mg/day vs 1.35 ± 0.84 mg/day (P = 0.005), respectively. Multiple regression analysis, including patient age and both the CYP2C9 and CYP2C19 genes, showed that these variables explained more than 20% of the dose variations. This is the first report in Mexico searching for the relationship between CYP450 and APOE polymorphisms and the dose requirements of acenocoumarol. Our results suggest that, in the Mexican population, CYP2C19 is more involved in acenocoumarol metabolism than CYP2C9 and APOE. Besides considering the age factor, pharmacogenetic testing for CYP2C19 2 before initiating acenocoumarol treatment could lead to a safer anticoagulation therapy in Mexican patients.

Adrenal hypofunction from histoplasmosis: a literature review from 1971 to 2012.

PURPOSE: While histoplasmosis has been reported from most continents, the disease is most often recognized in the midwestern United States. The recent diagnosis of adrenal hypofunction in two patients with progressive disseminated histoplasmosis (PDH) in our hospital led us to review the literature. METHODS: We reviewed PubMed using the search term "adrenal histoplasmosis" for the years 1971 to 2012. RESULTS: The results included 242 patients with adrenal histoplasmosis from either case reports or case series. Most of the reported patients were from countries not previously considered to be heavily endemic for histoplasmosis. In addition, 41.3 % of patients with adrenal involvement developed adrenal hypofunction. CONCLUSION: As modern technology elucidates more cases of adrenal histoplasmosis, the global boundaries of endemicity are being redefined.

Genetic variants associated with deep vein thrombosis: the F11 locus.

BACKGROUND: Recent studies have found associations between deep vein thrombosis (DVT) and single nucleotide polymorphisms (SNPs) in a 4q35.2 locus that contains genes encoding factor XI (F11), a cytochrome P450 family member (CYP4V2), and prekallikrein (KLKB1). OBJECTIVE: We investigated which of the common SNPs in this locus are independently associated with DVT. METHODS: The study populations were the Leiden Thrombophilia Study (LETS) (443 DVT cases and 453 controls) and the Multiple Environmental and Genetic Assessment of risk factors for venous thrombosis (MEGA study) (2712 DVT cases and 4634 controls). We assessed the association between DVT and 103 SNPs in a 200 kb region using logistic regression. RESULTS: We found that two SNPs (rs2289252 and rs2036914 in F11) were independently associated with DVT. After adjusting for age, sex, and the other SNP, the odds ratios (risk vs. non-risk homozygotes) of these two SNPs were 1.49 for rs2289252 (95% CI, 1.25-1.76) and 1.33 for rs2036914 (95% CI, 1.11-1.59). We found that rs2289252 was also associated with FXI levels, as has been previously reported for rs2036914; these two SNPs remained associated with DVT with somewhat attenuated risk estimates after adjustment for FXI levels. CONCLUSION: Two SNPs, rs2289252 and rs2036914 in F11, appear to independently contribute to the risk of DVT, a contribution that is explained at least in part by an association with FXI levels.

Factor V Leiden and thrombosis in patients with systemic lupus erythematosus: a meta-analysis.

The aim of this study was to perform a meta-analysis of the association between the factor V Leiden polymorphism (FVL) and thrombosis among patients with systemic lupus erythematosus (SLE) and/or antiphospholipid antibody (aPL) positivity. Included studies recruited patients based on SLE or aPL-positive status, confirmed subjects' SLE diagnosis as defined by the American College of Rheumatology, and documented thrombotic events. Excluded studies were non-English or considered only arterial thrombosis. Individual patient data, available from 5 studies, together with unpublished data from 1210 European-American SLE patients from the UCSF Lupus Genetics Collection genotyped for FVL, were further analyzed. Seventeen studies (n=2090 subjects) were included in the initial meta-analysis. Unadjusted odds ratios (OR) were calculated to assess association of FVL with thrombosis. The OR for association of thrombosis with FVL was 2.88 (95% confidence interval (CI) 1.98-4.20). In the secondary analysis with our individual patient dataset (n=1447 European-derived individuals), SLE subjects with the FVL polymorphism still had more than two times the odds of thrombosis compared to subjects without this polymorphism, even when adjusting for covariates such as gender, age and aPL status. SLE and/or aPL-positive patients with the FVL variant have more than two times the odds of thrombosis compared to those without this polymorphism.

Detailed genetic characterization of the interleukin-23 receptor in psoriasis.

Using a multi-tiered, case-control association design, scanning 25 215 gene-centric SNPs, we previously identified two psoriasis susceptibility genes: IL12B and IL23R. These results have recently been confirmed. To better characterize the IL23R psoriasis-association, we used a fine mapping strategy to identify 59 additional IL23R-linked SNPs, which were genotyped in our three independent, white North American sample sets (>2800 individuals in toto). A sliding window of haplotype association demonstrates colocalization of psoriasis susceptibility effects within the boundaries of IL23R across all sample sets, thereby decreasing the likelihood that neighboring genes, particularly IL12RB2, are driving the association at this region. Additional haplotype work identified two 5-SNP haplotypes with strong protective effects, consistent across our three sample sets (OR(common)=0.67; P(comb)=4.32E-07). Importantly, heterogeneity of effect was extremely low between sample sets for these haplotypes (P(Het)=0.961). Together, these protective haplotypes attain a frequency of 16% in controls, declining to 11% in cases. The characterization of association patterns within IL23R to specific predisposing/protective variants will play an important role in the elucidation of psoriasis etiology and other related phenotypes. Further, this work is essential to lay the foundation for the role of IL23R genetics in response to pharmaceutical therapy and dosage.

Variants in the 5q31 cytokine gene cluster are associated with psoriasis.

A multitiered genetic association study of 25 215 single-nucleotide polymorphisms (SNPs) in three case-control sample sets (1446 patients and 1432 controls) identified three IL13-linked SNPs (rs1800925, rs20541 and rs848) associated with psoriasis. Although the susceptibility effects at these SNPs were modest (joint allelic odds ratios (ORs): 0.76 to 0.78; P(comb): 1.3E-03 to 2.50E-04), the association patterns were consistent across the sample sets, with the minor alleles being protective. Haplotype analyses identified one common, susceptible haplotype CCG (joint allelic OR=1.27; P(comb)=1.88E-04) and a less common, protective haplotype TTT (joint allelic OR=0.74; P(comb)=7.05E-04). In combination with the other known genetic risk factors, HLA-C, IL12B and IL23R, the variants reported here generate an 11-fold psoriasis-risk differential. Residing in the 5q31 cytokine gene cluster, IL13 encodes an important T-cell-derived cytokine that regulates cell-mediated immunity. These results provide the foundation for additional studies required to fully dissect the associations within this cytokine-rich genomic region, as polymorphisms in closely linked candidate genes, such as IRF1, IL5 or IL4, may be driving these results through linkage disequilibrium.

Schilbach-Rott syndrome in a third family: further delineation of an autosomal dominant trait.

We describe a father-son Mexican pair with typical features of Schilbach-Rott syndrome (SRS): ocular hypotelorism, cleft palate, hypospadias (only in the child), and microcephaly. This observation documents for the first time a male to male transmission and therefore confirms that the SRS is inherited as an autosomal dominant trait with variable expressivity.

A bacterial artificial chromosome library for sequencing the complete human genome.

A 30-fold redundant human bacterial artificial chromosome (BAC) library with a large average insert size (178 kb) has been constructed to provide the intermediate substrate for the international genome sequencing effort. The DNA was obtained from a single anonymous volunteer, whose identity was protected through a double-blind donor selection protocol. DNA fragments were generated by partial digestion with EcoRI (library segments 1--4: 24-fold) and MboI (segment 5: sixfold) and cloned into the pBACe3.6 and pTARBAC1 vectors, respectively. The quality of the library was assessed by extensive analysis of 169 clones for rearrangements and artifacts. Eighteen BACs (11%) revealed minor insert rearrangements, and none was chimeric. This BAC library, designated as "RPCI-11," has been used widely as the central resource for insert-end sequencing, clone fingerprinting, high-throughput sequence analysis and as a source of mapped clones for diagnostic and functional studies.

A physical map of the human genome.

The human genome is by far the largest genome to be sequenced, and its size and complexity present many challenges for sequence assembly. The International Human Genome Sequencing Consortium constructed a map of the whole genome to enable the selection of clones for sequencing and for the accurate assembly of the genome sequence. Here we report the construction of the whole-genome bacterial artificial chromosome (BAC) map and its integration with previous landmark maps and information from mapping efforts focused on specific chromosomal regions. We also describe the integration of sequence data with the map.

The physical maps for sequencing human chromosomes 1, 6, 9, 10, 13, 20 and X.

We constructed maps for eight chromosomes (1, 6, 9, 10, 13, 20, X and (previously) 22), representing one-third of the genome, by building landmark maps, isolating bacterial clones and assembling contigs. By this approach, we could establish the long-range organization of the maps early in the project, and all contig extension, gap closure and problem-solving was simplified by containment within local regions. The maps currently represent more than 94% of the euchromatic (gene-containing) regions of these chromosomes in 176 contigs, and contain 96% of the chromosome-specific markers in the human gene map. By measuring the remaining gaps, we can assess chromosome length and coverage in sequenced clones.

Semiautomated clone verification by real-time PCR using molecular beacons.

Conventional, high-throughput PCR analysis of common elements utilizing numerous primer sets and template DNA requires multiple rounds of PCR to ensure optimal conditions. Laborious gel electrophoresis and staining is then necessary to visualize amplification products. We propose novel multicolor molecular beacons, to establish a high-throughput, PCR-based sequence tagged site (STS) detection system that swiftly and accurately confirms marker content in template containing common repeat elements. A simple, one-tube, real-time PCR assay system was developed to specifically detect regions containing CA and GATA repeats. Ninety-six samples can be confirmed for marker content in a closed-tube format in 3 h, eliminating product confirmation on agarose gels and avoiding crossover contamination. Multiple STSs can be detected simultaneously in the same reaction tube by utilizing molecular beacons labeled with multicolor fluorophores. Template DNA from 260 RPCI-11 bacterial artificial chromosome (BAC) clones was examined for the presence of CA and/or GATA repeats using molecular beacon PCR and compared with conventional PCR results of the same clones. Of the 205 clones containing CA and GATA repeats, we were able to identify 129 clones (CA, n = 99; GATA, n = 30) by using molecular beacons and only 121 clones (CA, n = 92; GATA, n = 29) by conventional PCR amplification. As anticipated, 55 clones that contained sequences other than CA or GATA failed molecular beacon detection. Molecular beacon PCR, employing beacons specific for tandem repeat elements, provides a fast, accurate, and sensitive multiplex detection assay that will expedite verification of marker content in a multitude of template containing these repeats.

A BAC-based physical map of the major autosomes of Drosophila melanogaster.

We constructed a bacterial artificial chromosome (BAC)-based physical map of chromosomes 2 and 3 of Drosophila melanogaster, which constitute 81% of the genome. Sequence tagged site (STS) content, restriction fingerprinting, and polytene chromosome in situ hybridization approaches were integrated to produce a map spanning the euchromatin. Three of five remaining gaps are in repeat-rich regions near the centromeres. A tiling path of clones spanning this map and STS maps of chromosomes X and 4 was sequenced to low coverage; the maps and tiling path sequence were used to support and verify the whole-genome sequence assembly, and tiling path BACs were used as templates in sequence finishing.

Bacterial artificial chromosome libraries for mouse sequencing and functional analysis.

Bacterial artificial chromosome (BAC) and P1-derived artificial chromosome (PAC) libraries providing a combined 33-fold representation of the murine genome have been constructed using two different restriction enzymes for genomic digestion. A large-insert PAC library was prepared from the 129S6/SvEvTac strain in a bacterial/mammalian shuttle vector to facilitate functional gene studies. For genome mapping and sequencing, we prepared BAC libraries from the 129S6/SvEvTac and the C57BL/6J strains. The average insert sizes for the three libraries range between 130 kb and 200 kb. Based on the numbers of clones and the observed average insert sizes, we estimate each library to have slightly in excess of 10-fold genome representation. The average number of clones found after hybridization screening with 28 probes was in the range of 9-14 clones per marker. To explore the fidelity of the genomic representation in the three libraries, we analyzed three contigs, each established after screening with a single unique marker. New markers were established from the end sequences and screened against all the contig members to determine if any of the BACs and PACs are chimeric or rearranged. Only one chimeric clone and six potential deletions have been observed after extensive analysis of 113 PAC and BAC clones. Seventy-one of the 113 clones were conclusively nonchimeric because both end markers or sequences were mapped to the other confirmed contig members. We could not exclude chimerism for the remaining 41 clones because one or both of the insert termini did not contain unique sequence to design markers. The low rate of chimerism, approximately 1%, and the low level of detected rearrangements support the anticipated usefulness of the BAC libraries for genome research.