Diagnostic per-lesion performance of a simulated gadoxetate disodium-enhanced abbreviated MRI protocol for hepatocellular carcinoma screening.

AIM: To evaluate the diagnostic per-lesion performance of a simulated gadoxetate disodium-enhanced abbreviated MRI (AMRI) in cirrhotic and chronic hepatitis B (CHB) patients for hepatocellular carcinoma (HCC) screening. MATERIALS AND METHODS: Seventy-nine consecutive patients at risk for HCC due to cirrhosis and/or CHB were included in this retrospective study. For each patient, the first gadoxetate disodium-enhanced MRI between 2008 through 2014 was analysed. Two independent readers read an anonymised abbreviated image set comprising axial T1-weighted (W) images with fat saturation in the hepatobiliary phase, 20 minutes or more after gadoxetate injection, and axial T2W single-shot fast spin echo images. Each observation >10 mm was scored as negative or suspicious for HCC. Inter-reader agreement was assessed. A composite reference standard was used to determine the per-lesion diagnostic performance for each reader. RESULTS: Inter-reader agreement was substantial (κ = 0.75). The final reference standard showed 27 HCCs in 13 patients (median 21 mm, range 11-100 mm). The two readers each correctly scored 23 as suspicious for HCC (sensitivity = 85.2%), scored a total of 27 and 32 observations as suspicious for HCC (positive predictive value [PPV] = 85.2% and 71.9%), and scored 83 and 78 observations or complete examinations as negative for HCC (negative predictive value [NPV] = 95.2% and 94.9%). CONCLUSIONS: The AMRI protocol provides higher per-lesion sensitivity and NPV than reported values for ultrasound, the current recommended technique for screening, and similar per-lesion sensitivity and PPV to reported values for complete dynamic contrast-enhanced MRI.

Alpha-thalassemia intellectual disability: variable phenotypic expression among males with a recurrent nonsense mutation - c.109C>T (p.R37X).

Alpha-thalassemia intellectual disability, one of the recognizable X-linked disability syndromes, is characterized by short stature, microcephaly, distinctive facies, hypotonic appearance, cardiac and genital anomalies, and marked skewing of X-inactivation in female carriers. With the advent of next generation sequencing, mutations have been identified that result in less severe phenotypes lacking one or more of these phenotypic manifestations. Here we report five unrelated kindreds in which a c.109C>T (p.R37X) mutation segregates with a variable but overall milder phenotype. The distinctive facial appearance of alpha-thalassemia intellectual disability was present in only one of the 18 affected males evaluated beyond the age of puberty, although suggestive facial appearance was present in several during infancy or early childhood. Although the responsible genetic alteration is a nonsense mutation in exon 2 of ATRX, the phenotype appears to be partially rescued by the production of alternative transcripts and/or other molecular mechanisms.

Identifying individuals by sequencing mitochondrial DNA from teeth.

Mitochondrial DNA (mtDNA) was extracted from teeth stored from 3 months to 20 years, including teeth from the semi-skeletonized remains of a murder victim which had been buried for 10 months. Tooth donors and/or their maternal relatives provided blood or buccal cells, from which mtDNA was also extracted. Enzymatic amplification and direct sequencing of roughly 650 nucleotides from two highly polymorphic regions of mtDNA yielded identical sequences for each comparison of tooth and fresh DNA. Our results suggest that teeth provide an excellent source for high molecular weight mtDNA that can be valuable for extending the time in which decomposed human remains can be genetically identified.

Familial male breast cancer is not linked to the BRCA1 locus on chromosome 17q.

Breast cancer in men is about a hundredfold less common than in women and this has hindered research into its genetic basis. We have examined 22 families with at least one case of male breast cancer for linkage to the hereditary breast and ovarian cancer locus, BRCA1, on chromosome 17q. We found strong evidence against linkage to BRCA1 (lod score-16.63) and the best estimate of the proportion of linked families was 0% (95% CI 0-18%). Our results indicate that there is a gene(s) other than BRCA1 which predisposes to early-onset breast cancer in women and which confers a higher risk of male breast cancer. Identification of additional pedigrees that include cases of male breast cancer may therefore facilitate the mapping and isolation of this gene.

Confirmation of BRCA1 by analysis of germline mutations linked to breast and ovarian cancer in ten families.

We provide genetic evidence supporting the identity of the candidate gene for BRCA1 through the characterization of germline mutations in 63 breast cancer patients and 10 ovarian cancer patients in ten families with cancer linked to chromosome 17q21. Nine different mutations were detected by screening BRCA1 DNA and RNA by single-strand conformation polymorphism analysis and direct sequencing. Seven mutations lead to protein truncations at sites throughout the gene. One missense mutation (which occurred independently in two families) leads to loss of a cysteine in the zinc binding domain. An intronic single basepair substitution destroys an acceptor site and activates a cryptic splice site, leading to a 59 basepair insertion and chain termination. The four families with both breast and ovarian cancer had chain termination mutations in the N-terminal half of the protein.

Growth retardation and tumour inhibition by BRCA1.

Inherited mutations in BRCA1 predispose to breast and ovarian cancer, but the role of BRCA1 in sporadic breast and ovarian cancer has previously been elusive. Here, we show that retroviral transfer of the wild-type BRCA1 gene inhibits growth in vitro of all breast and ovarian cancer cell lines tested, but not colon or lung cancer cells or fibroblasts. Mutant BRCA1 has no effect on growth of breast cancer cells; ovarian cancer cell growth is not affected by BRCA1 mutations in the 5' portion of the gene, but is inhibited by 3' BRCA1 mutations. Development of MCF-7 tumours in nude mice is inhibited when MCF-7 cells are transfected with wild-type, but not mutant, BRCA1. Most importantly, among mice with established MCF-7 tumours, peritoneal treatment with a retroviral vector expressing wild-type BRCA1 significantly inhibits tumour growth and increased survival.

BRCA1 is secreted and exhibits properties of a granin.

Germline mutations in BRCA1 are responsible for most cases of inherited breast and ovarian cancer. However, the function of the BRCA1 protein has remained elusive. We now show that BRCA1 encodes a 190-kD protein with sequence homology and biochemical analogy to the granin protein family. Interestingly, BRCA2 also includes a motif similar to the granin consensus at the C terminus of the protein. Both BRCA1 and the granins localize to secretory vesicles, are secreted by a regulated pathway, are post-translationally glycosylated and are responsive to hormones. As a regulated secretory protein, BRCA1 appears to function by a mechanism not previously described for tumour suppressor gene products.

Mutations in COL11A2 cause non-syndromic hearing loss (DFNA13).

We report that mutation of COL11A2 causes deafness previously mapped to the DFNA13 locus on chromosome 6p. We found two families (one American and one Dutch) with autosomal dominant, non-syndromic hearing loss to have mutations in COL11A2 that are predicted to affect the triple-helix domain of the collagen protein. In both families, deafness is non-progressive and predominantly affects middle frequencies. Mice with a targeted disruption of Col11a2 also were shown to have hearing loss. Electron microscopy of the tectorial membrane of these mice revealed loss of organization of the collagen fibrils. Our findings revealed a unique ultrastructural malformation of inner-ear architecture associated with non-syndromic hearing loss, and suggest that tectorial membrane abnormalities may be one aetiology of sensorineural hearing loss primarily affecting the mid-frequencies.

A truncating mutation in GPSM2 is associated with recessive non-syndromic hearing loss.

Hereditary deafness is a genetically heterogeneous phenotype for which more than 100 genomic loci have been identified thus far. By analysis of a consanguineous Palestinian family, GPSM2 was recently discovered to be the cause of autosomal recessive non-syndromic hearing loss DFNB82. Here, we report a second truncating mutation, GPSM2 p.Q562X, identified via autozygosity mapping in a consanguineous Turkish family. This report provides evidence for allelic heterogeneity of GPSM2 and confirms its causative role for non-syndromic deafness.

The effect of citalopram treatment on amyloid-ß precursor protein processing and oxidative stress in human hNSC-derived neurons.

Selective Serotonin Reuptake Inhibitors (SSRIs) may hold therapeutic benefits for people with Alzheimer's disease (AD). SSRIs may perturb AD progression, or the conversion from MCI to AD, via increased neurogenesis, reduced oxidative stress and/or favourable Amyloid-ß Precursor Protein (AßPP) processing. This study used iPSC derived cortical neuronal cells carrying 3 different PSEN1 mutations, to investigate the effect of treatment with the SSRI, Citalopram on AßPP processing and oxidative stress. Control and PSEN1 mutation (L286V, A246E, M146L) iPSC-derived neurons were treated with Citalopram for 45 days. ADAM10 activity, AßPP processing and Aß generation was measured in addition to cellular redox status. Citalopram treatment reduced the Aß1-42:40 ratio in control but not in fAD PSEN1 cells. ADAM10 activity was increased with Citalopram treatments in fAD PSEN1 cell lines, which was also seen for sAßPPα secretion. Lower superoxide generation in fAD PSEN1 cells following Citalopram treatment was identified, although there was no effect on end markers of oxidative stress. Treatment with Citalopram appears to have little effect on Aß generation in fADPSEN1 cells, but our findings suggest that treatment can significantly increase non-amyloidogenic AßPP processing and reduce oxidative stress. These changes may explain why SSRIs appear most effective in the prodromal period of the disease progression, as opposed to reducing established AD pathology. Further investigation of specific pathways conferring the beneficial effects of SSRIs treatment are warranted.

A novel founder MSH2 deletion in Ethiopian Jews is mainly associated with early-onset colorectal cancer.

Lynch syndrome is an inherited cancer predisposition syndrome caused by germline defects in any of the mismatch repair (MMR) genes. Diagnosis of carriers makes precision prevention, early detection, and tailored treatment possible. Herein we report a novel founder deletion of 18,758 bp, mediated by Alu repeats on both sides, detected in Ethiopian Jews. The deletion, which encompasses exon 9-10 of the MSH2 coding sequence, is associated mainly with early-onset MSH2/MSH6-deficient colorectal cancer (CRC) and liposarcoma. Testing of 35 members of 5 seemingly unrelated families of Ethiopian origin yielded 10/21 (48%) carriers, of whom 9 had CRC. Age at first tumor diagnosis ranged from 16 to 89 years. Carriers from the oldest generations were diagnosed after age 45 years (mean 57), and carriers from the younger generation were diagnosed before age 45 years (mean 30). Awareness of this founder deletion is important to improve patient diagnosis, institute surveillance from an early age, and refer patients for genetic counseling addressing the risk of bi-allelic constitutional MMR deficiency syndrome.

Genetics of schizophrenia in the South African Xhosa.

Africa, the ancestral home of all modern humans, is the most informative continent for understanding the human genome and its contribution to complex disease. To better understand the genetics of schizophrenia, we studied the illness in the Xhosa population of South Africa, recruiting 909 cases and 917 age-, gender-, and residence-matched controls. Individuals with schizophrenia were significantly more likely than controls to harbor private, severely damaging mutations in genes that are critical to synaptic function, including neural circuitry mediated by the neurotransmitters glutamine, γ-aminobutyric acid, and dopamine. Schizophrenia is genetically highly heterogeneous, involving severe ultrarare mutations in genes that are critical to synaptic plasticity. The depth of genetic variation in Africa revealed this relationship with a moderate sample size and informed our understanding of the genetics of schizophrenia worldwide.

Genomic views of human history.

New tools of genomic analysis shed light on historical puzzles. Migrations of ancient peoples, differences in migration patterns of males and females, historical demography of cultures with ancient roots, and patterns of human genetic diversity are increasingly the focus of integrated analysis by historians, anthropologists, and geneticists.

Nonsyndromic deafness DFNA1 associated with mutation of a human homolog of the Drosophila gene diaphanous.

The gene responsible for autosomal dominant, fully penetrant, nonsyndromic sensorineural progressive hearing loss in a large Costa Rican kindred was previously localized to chromosome 5q31 and named DFNA1. Deafness in the family is associated with a protein-truncating mutation in a human homolog of the Drosophila gene diaphanous. The truncation is caused by a single nucleotide substitution in a splice donor, leading to a four-base pair insertion in messenger RNA and a frameshift. The diaphanous protein is a profilin ligand and target of Rho that regulates polymerization of actin, the major component of the cytoskeleton of hair cells of the inner ear.

Allele increasing susceptibility to human breast cancer may be linked to the glutamate-pyruvate transaminase locus.

The patterns of the occurrence of breast cancer in 11 high-risk families were evaluated by segregation and linkage analysis. These patterns were consistent with the hypothesis that increased susceptibility to breast cancer was inherited as an autosomal dominant allele with high penetrance in women. The postulated susceptibility allele in these families may be chromosomally linked to the glutamate-pyruvate transaminase (E.C. 2.6.1.2, alanine aminotransferase) locus. Confirmation of this linkage in other families would establish the existence of a gene increasing susceptibility to breast cancer. Since there is no association in the general population between a woman's glutamate-pyruvate transaminase genotype and her cancer risk, the glutamate-pyruvate transaminase linkage cannot be used as a screening test for breast cancer.

Linkage of early-onset familial breast cancer to chromosome 17q21.

Human breast cancer is usually caused by genetic alterations of somatic cells of the breast, but occasionally, susceptibility to the disease is inherited. Mapping the genes responsible for inherited breast cancer may also allow the identification of early lesions that are critical for the development of breast cancer in the general population. Chromosome 17q21 appears to be the locale of a gene for inherited susceptibility to breast cancer in families with early-onset disease. Genetic analysis yields a lod score (logarithm of the likelihood ratio for linkage) of 5.98 for linkage of breast cancer susceptibility to D17S74 in early-onset families and negative lod scores in families with late-onset disease. Likelihood ratios in favor of linkage heterogeneity among families ranged between 2000:1 and greater than 10(6):1 on the basis of multipoint analysis of four loci in the region.

Mutation in transcription factor POU4F3 associated with inherited progressive hearing loss in humans.

The molecular basis for autosomal dominant progressive nonsyndromic hearing loss in an Israeli Jewish family, Family H, has been determined. Linkage analysis placed this deafness locus, DFNA15, on chromosome 5q31. The human homolog of mouse Pou4f3, a member of the POU-domain family of transcription factors whose targeted inactivation causes profound deafness in mice, was physically mapped to the 25-centimorgan DFNA15-linked region. An 8-base pair deletion in the POU homeodomain of human POU4F3 was identified in Family H. A truncated protein presumably impairs high-affinity binding of this transcription factor in a dominant negative fashion, leading to progressive hearing loss.

Comparison of the Simplify D-dimer assay performed at the bedside with a laboratory-based quantitative D-dimer assay for the diagnosis of pulmonary embolism in a low prevalence emergency department population.

BACKGROUND: The immunofiltration D-dimer assay could allow point-of-care testing for pulmonary embolism (PE). A study was undertaken to compare a clinician-performed qualitative D-dimer assay with the automated quantitative D-dimer test. METHODS: A prospective observational study was conducted from January to October 2005 at an urban academic emergency department (ED). 1193 patients of mean (SD) age 47 (16) years (66% female) were enrolled. The study protocol combined pretest probability estimation, D-dimer testing by both a qualitative immunochromatographic assay (Simplify) performed at the point of care by 192 different clinicians and a quantitative D-dimer test performed in a CLIA-certified laboratory. The criterion standard was image-proven PE or deep venous thrombosis within 45 days after enrollment. To test interobserver agreement for the qualitative assay, two blinded observers independently read 841 Simplify cartridges. RESULTS: Of 1193 patients enrolled, 45 were PE+ (3.8%, 95% CI 2.8% to 5.0%). Qualitative results were available for 1169 (98%) and quantitative results were available for 1136 (95%). Comparison of the qualitative and quantitative D-dimer tests gave the following results: sensitivity 91% (95% CI 78% to 98%) vs 93% (95% CI 80% to 98%); specificity 57% (95% CI 54% to 60%) vs 57% (95% CI 54% to 60%); likelihood ratio negative 0.16 (95% CI 0.06 to 0.37) vs 0.13 (95% CI 0.05 to 0.35). The weighted Cohen's kappa for interpretation of the qualitative assay was 0.69 (95% CI 0.63 to 0.76). CONCLUSIONS: In this very low-risk ED population, a qualitative D-dimer assay performed at the point of care had similar diagnostic accuracy to the quantitative D-dimer test. Interobserver agreement for the qualitative test was good.