Short-term outcome of periviable small-for-gestational-age babies: is our counseling up to date?

OBJECTIVE: There are limited data for counseling on and management of periviable small-for-gestational-age (SGA) fetuses. We therefore aimed to investigate the short-term outcome of periviable SGA fetuses in relation to the likely underlying cause. METHODS: This was a retrospective study of data from three London tertiary fetal medicine centers obtained between 2000 and 2015. We included viable singleton pregnancies with a severely small fetus, defined as those with an abdominal circumference ≤ 3rd percentile, identified between 22 + 0 and 25 + 6 weeks' gestation. Data obtained included fetal biometry, presence of placental anomalies, uterine and fetal Doppler and neonatal outcome. We excluded cases with structural abnormalities, proven or suspected abnormal karyotype or genetic syndromes. Cases were classified according to the suspected underlying cause of the small fetal size into one of the following categories: uteroplacental insufficiency, evidence of placental damage with normal uterine artery Doppler, viral infection, or unclassied. RESULTS: There were 245 cases included in the study. Of these, at diagnosis of SGA, 201 (82%) were categorized as uteroplacental cause, 13 (5%) as suspected placental cause, one (0.4%) as suspected viral cause and 30 (12%) could not be assigned to any of these categories. Overall, 101 (41%) cases survived the neonatal period; 89 (36%) underwent in-utero fetal demise, 22 (9%) died neonatally and 33 (14%) pregnancies were terminated. The diagnosis-to-delivery interval was 8.1 weeks in those that survived and 4.5 weeks in those that died neonatally. CONCLUSIONS: Almost 90% of periviable SGA cases are associated with uteroplacental insufficiency or intraplacental damage. Survival is related to gestational age at delivery, with outcomes better than might be assumed at diagnosis and some pregnancies reaching term. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Multiplex MassARRAY spectrometry (iPLEX) produces a fast and economical test for 56 familial hypercholesterolaemia-causing mutations.

Familial hypercholesterolaemia (FH) is a common single gene disorder, pre-disposing to cardiovascular disease, which is most commonly caused by mutations in the LDL-receptor (LDLR) gene. About 5% of patients carry the p.R3527Q (previously R3500Q) mutation in the apolipoprotein B (APOB) gene and 2% carry the p.D374Y mutation in the PCSK9 gene, but the lack of high-throughput methods make routine genetic diagnosis difficult. In this study, we developed an iPLEX MassARRAY Spectrometry mutation test to identify 56 mutations (54 in the LDLR gene, 1 in the APOB gene and 1 in the PCSK9 gene). The iPLEX test was verified by analysing 150 DNA samples from FH patients with a previously characterized mutation and 96 no-mutation control samples. Mutations were identified in all 150 FH mutation-positive samples using the iPLEX assay, with 96% directly called by the software. The false-positive rate in no-mutation control samples was 0.015%. The overall specific mutation assay failure rate was 2.1%. In the UK, this gives an average detection rate of 75%.The FH iPLEX test is not only designed for large-scale targeted population screening for FH mutations, such as lipid clinic patients, but can also be used for population screening. The assay can easily be developed further to include additional FH-causing mutations, thus increasing the sensitivity of the diagnostic assay.

The CTLA4 +49 A/G*G-CT60*G haplotype is associated with susceptibility to multiple sclerosis in Flanders.

Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system white matter characterized by inflammation, demyelination and axonal damage. The cytotoxic T lymphocyte antigen-4 (CTLA-4) protein plays a key role in the down-regulation of T cell activation. We analysed the CTLA4 +49A/G and CT60 polymorphisms in a cohort of 120 MS trio families recruited from the Flanders region in Belgium. Both polymorphisms were genotyped by polymerase chain reaction-restriction fragment length polymorphism (RFLP). The +49 G-allele was significantly more transmitted to affected probands (P = 0.005). No transmission distortion was observed for the CT60 polymorphism. Haplotype analysis revealed significant overtransmission of the +49 A/G*G-CT60*G haplotype (P = 0.0025), and undertransmission of the +49 A/G*A-CT60*G haplotype (P = 0.015). The CTLA4 gene has been the focus of intense investigation in MS. Of 15 recently published papers, only six reported significant associations of various CTLA4 polymorphisms with MS, with the remainder being negative. Ours is the first report investigating the CT60 polymorphism in MS. Our data highlight a need for further scrutiny of the CTLA4 gene in MS.

BACE1 polymorphisms do not influence platelet membrane beta-secretase activity or genetic susceptibility for Alzheimer's disease in the Northern Irish population.

Beta-site amyloid precursor protein (APP)-cleaving enzyme 1 (BACE1) is a biological and positional candidate gene for Alzheimer's disease (AD). BACE1 is a protease that catalyses APP cleavage at the beta-secretase site. We evaluated all common and putatively functional polymorphisms in the genomic region encompassing BACE1 for an association with AD, and for functional effects on platelet beta-secretase activity. Tag SNPs (n = 10) derived from phase II of the International HapMap Project, and a nonsynonymous variant, were successfully genotyped in 901 Caucasian individuals from Northern Ireland using Sequenom iPLEX and TaqMan technologies. APOE genotyping was performed by PCR-RFLP. Platelet membrane beta-secretase activity was assayed in a subset of individuals (n = 311). Hardy-Weinberg equilibrium was observed for all variants. Evidence for an association with AD was observed with multi-marker haplotype analyses (P = 0.01), and with rs676134 when stratified for APOE genotype (P = 0.02), however adjusting for multiple testing negated the evidence for association of this variant with AD. chi(2) analysis of genotype and allele frequencies in cases versus controls for individual SNPs revealed no evidence for association (5% level). No genetic factors were observed that significantly influenced platelet membrane beta-secretase activity. We have selected an appropriate subset of variants suitable for comprehensive genetic investigation of the BACE1 gene. Our results suggest that common BACE1 polymorphisms and putatively functional variants have no significant influence on genetic susceptibility to AD, or platelet beta-secretase activity, in this Caucasian Northern Irish population.

Association of functional heme oxygenase-1 gene promoter polymorphism with renal transplantation outcomes.

Heme oxygenase-1 (HO-1) is a cytoprotective molecule and increased expression in experimental transplant models correlates with reduced graft injury. A functional dinucleotide repeat (GT)(n) polymorphism, within the HO-1 promoter, regulates gene expression; a short number of repeats (S-allele <25) increases transcription. The role of this HO-1 gene promoter polymorphism on renal transplant outcomes was assessed. DNA from 707 donor/recipient pairs (n = 1414) of first deceased donor renal transplants (99% Caucasian) was genotyped. Graft survival was not significantly impacted by carriage of an S-allele by the donor (hazard ratio 0.89, 95% CI 0.71-1.11; p = 0.28) or recipient (hazard ratio 1.19, 95% CI 0.95-1.48; p = 0.13). Similarly neither donor nor recipient genotype influenced recipient survival (hazard ratio 0.89, 95% CI 0.67-1.18; p = 0.41, and hazard ratio 1.22, 95% CI 0.93-1.62; p = 0.16). The hazard ratios changed only minimally in multivariate analysis including significant survival factors. Genotype did not alter the incidence of acute rejection or chronic allograft nephropathy. There is no evidence of a protective effect for the S-allele of the HO-1 gene promoter polymorphism on graft or recipient survival in clinical renal transplantation.

The CTLA4+49A/G and CT60 polymorphisms and chronic inflammatory arthropathies in Northern Ireland.

Rheumatoid and juvenile idiopathic arthritis (RA, JIA) are chronic inflammatory arthropathies with an autoimmune background. The cytotoxic T-lymphocyte antigen-4 (CTLA-4) protein plays a key role in the down-regulation of T cell activation. We analyzed the CTLA4 +49A/G and CT60 polymorphisms in cohorts of Northern Irish RA and JIA patients and healthy control subjects using restriction fragment length polymorphism methods. The +49 A allele was increased in RA (61.2%; P=0.02; OR=1.28; 95% C.I.=1.04-1.58) and JIA (61.8%; P=0.14) patients compared to the control population (55.3%). No significant association was observed for the CT60 polymorphism. Haplotype analysis revealed a significantly different distribution of +49 A/G-CT60 haplotypes in RA and JIA patients compared to controls (P value<0.00001 and 0.030 for comparison of RA and JIA patients with controls, respectively). Our results suggest that the CTLA-4 gene is involved in predisposition to inflammatory arthropathies in the Northern Irish population.

Mapping candidate non-MHC susceptibility regions to multiple sclerosis.

Understanding the genetic basis of multiple sclerosis (MS) remains a major challenge, despite decades of intensive research. In order to identify candidate non-MHC susceptibility regions to MS, the results of whole genome screens for linkage or association and follow-up studies in 18 different populations were superimposed together in a combined genomic map. Analysis of this map led to the prediction of at least 38 potential susceptibility regions, each showing linkage and/or association in several populations. Among these, 17 regions were the most reproducibly reported in these studies, thus representing top predicted candidates for MS. This non-formal approach to meta-analysis demonstrated the ability to verify results and retrieve lost information in an association study. Assessment of the map in a Northern Irish refined screen (n=415 cases, n=490 controls) revealed association in 15 regions (P<0.05), including 10 promising candidates on chromosomes 1p13, 2p13, 2q14, 3p23, 7q21, 13q14, 15q13, 17p13, 18q21 and 20p12 (P<0.0025). Seven of these regions were previously overlooked in the Northern Irish whole genome association study. Collating results from numerous studies, this draft map represents a tool that should facilitate the analysis of the genetic backgrounds of MS in many populations.

Polymorphisms in the interleukin-4 and IL-4 receptor genes and multiple sclerosis: a study in Spanish-Basque, Northern Irish and Belgian populations.

Cytokine gene polymorphisms are known to influence susceptibility and disease course of many autoimmune diseases. Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system white matter characterized by inflammation, demyelination and axonal damage. We analysed both the well-known intronic variable number of tandem repeat (VNTR) and +33 C/T single-nucleotide polymorphisms (SNP) in the IL-4 gene, as well as the functional Q551R SNP in the IL4-R gene in a cohort of three distinct populations comprising sporadic cases and controls from the northern Spanish Basque Country and Northern Ireland, as well as family trios from Belgium. The IL-4 +33 TT genotype was decreased in primary progressive (PP) versus relapsing-remitting (RR) patients in the Northern Irish population (OR = 0.14; 95% CI = 0.018-1.09). Two-marker haplotype distribution of the VNTR and +33 C/T SNP in PP patients differed from that seen in RR patients in Northern Ireland (P = 0.03). The R allele of the Q551R SNP was significantly under-transmitted in the Belgian trio families (P = 0.003), although this effect was not seen in the Northern Irish and Basque data sets. We did not identify IL-4-IL4-R gene-gene interaction in determining susceptibility or clinical parameters of MS. Disease or genetic heterogeneity or both may be responsible for the observed lack of reproduction in different populations. Our data reinforce recent findings for a role of IL4-R in susceptibility to MS.

IFNG polymorphisms are associated with gender differences in susceptibility to multiple sclerosis.

Interferon-gamma (IFNgamma) treatment is deleterious in multiple sclerosis (MS). MS occurs twice as frequently in women as in men. IFNgamma expression varies by gender. We studied a population-based sample of US MS patients and ethnicity-matched controls and independent Northern Irish and Belgian hospital-based patients and controls for association with MS, stratified by gender, of an intron 1 microsatellite [I1(761)*CAn], a single nucleotide polymorphism 3' of IFNG [3'(325)*G --> A] and three flanking microsatellite markers spanning a 118 kb region around IFNG. Men carriers of the 3'(325)*A allele have increased susceptibility to MS compared to noncarriers in the USA (P=0.044; OR: 2.58, 95% CI: 0.97-8.08) and Northern Ireland (P=0.019; OR: 2.37, 95% CI: 1.10-5.13). There is a nonsignificant trend in the same direction in Belgian men (P=0.299; OR: 1.50, 95% CI: 0.71-3.26). Men carriers of I1(761)*CA13, which is in strong linkage disequilibrium with the 3'(325)*A, have increased susceptibility (P=0.050; OR: 2.22, 95% CI: 0.98-5.40), while men carriers of I1(761)*CA12 have decreased susceptibility (P=0.022; OR: 0.46, 95% CI: 0.23-0.90) to MS in the USA. Similar associations were reported in Sardinia between the I1(761)*CA12 allele and reduced risk of MS in men. Flanking markers were not associated with MS susceptibility. Polymorphisms of IFNG may contribute to differences in susceptibility to MS between men and women.

Linkage disequilibrium analysis of chromosome 12q14-15 in multiple sclerosis: delineation of a 118-kb interval around interferon-gamma (IFNG) that is involved in male versus female differential susceptibility.

We have recently reported the association of a polymorphic intronic CA-repeat in the interferon-gamma gene (IFNG) with gender bias in susceptibility to multiple sclerosis (MS) in a Sardinian population. This association could refer to a functional polymorphism within IFNG or could be due to linkage disequilibrium between the IFNG marker and a neighbouring susceptibility locus. Within the average reach of linkage disequilibrium, various other candidate genes are located. Among these the most striking ones are the genes coding for the cytokines interleukin-22 (IL-22) and interleukin-26 (IL-26) that constitute together with IFNG a cytokine cluster on chromosome 12q14. To determine more precisely the location of this gender-associated susceptibility locus, we have now performed a more extensive linkage disequilibrium screen of this region using nine additional microsatellite markers. This locus appeared to be confined to a 118-kb interval that is bordered by the markers D12S313 and D12S2511, in which IFNG itself remains the main candidate gene. Haplotype analysis confirmed that this MS-associated locus protects males from developing MS according to a recessive or allele-dosage model. Our results indicate that the well-documented gender differences in susceptibility to MS are at least partially caused by genetic factors in the region surrounding IFNG.

Influence of CCR5 delta32 polymorphism on multiple sclerosis susceptibility and disease course.

The CCR5 chemokine receptor has been implicated in the pathogenesis of multiple sclerosis (MS). We carried out an allelic association study using a deletion polymorphism in the coding region of the CCR5 gene in 331 relapsing-remitting (RR) and secondary progressive (SP) MS patients, 108 primary progressive (PP) MS patients and 230 healthy controls. Of the 331 RR and SPMS patients, 172 were recruited from specialist clinics and 159 from a population survey. Disease severity was assessed clinically using the Expanded Disability Status Scale (EDSS) and used to calculate a progression index for each patient (defined as EDSS divided by duration of disease). No significant difference in distribution of the CCR5 delta32 allele was observed between the 331 RR/SPMS patients and controls, between the 108 PPMS patients and controls or between the PPMS and RR/SPMS groups. Furthermore, no differences in rate of disease progression were detected between carriers and noncarriers of the delta32 allele. In the population-based group of RR/SPMS patients, carriage of the CCR5 delta32 polymorphism was associated with a lower age at disease onset (mean age 26.562 versus 31.065 years, P = 0.003). However, no significant differences in age of onset were present in the PPMS group or in a second RRMS population. These results suggest that the CCR5 delta32 polymorphism is not a major determinant of susceptibility to develop MS in the population under study, and conflict with a previously reported association between CCR5 delta32 carriage and a better prognosis.

Polymorphisms in the interferon-gamma/interleukin-26 gene region contribute to sex bias in susceptibility to rheumatoid arthritis.

OBJECTIVE: To determine whether polymorphisms in the interferon-gamma (IFNgamma)/interleukin-26 (IL-26; formerly, AK155) gene cluster contribute to sex-based differential susceptibility to rheumatoid arthritis (RA). METHODS: Four microsatellite markers, located in a 118-kb interval that contains both the IFNgamma and IL-26 genes on chromosome 12q15, were typed in 251 patients with RA and 198 unrelated healthy controls (all of whom lived in Northern Ireland) by means of polymerase chain reaction-based fragment analysis. RESULTS: Marker D12S2510, which is located 3 kb 3' from the IL-26 gene, was significantly associated with RA in women (corrected P [P(corr)] = 0.008, 2 degrees of freedom [2 df]) but not in men (P = 0.99, 2 df). A 3-marker haplotype, IFNGCA*13;D12S2510*8;D12S2511*9, was inferred that showed significant underrepresentation in women with RA (odds ratio 0.50, 95% confidence interval 0.32-0.78; P = 0.002, P(corr) = 0.03) but not in men with RA. CONCLUSION: Our results demonstrate that common polymorphisms in the IFNgamma/IL-26 gene region may contribute to sex bias in susceptibility to RA, by distorting the propensity of female carriers versus male carriers to contract this disease. These results conform to our recent observations of a role for this gene cluster in sex-based differential susceptibility to another Th1-type inflammatory disease, multiple sclerosis.