Rare variants in the CYP27B1 gene are associated with multiple sclerosis.

OBJECTIVE: Multiple sclerosis (MS) is a complex neurological disease. Genetic linkage analysis and genotyping of candidate genes in families with 4 or more affected individuals more heavily loaded for susceptibility genes has not fully explained familial disease clustering. METHODS: We performed whole exome sequencing to further understand the heightened prevalence of MS in these families. RESULTS: Forty-three individuals with MS (1 from each family) were sequenced to find rare variants in candidate MS susceptibility genes. On average, >58,000 variants were identified in each individual. A rare variant in the CYP27B1 gene causing complete loss of gene function was identified in 1 individual. Homozygosity for this mutation results in vitamin D-dependent rickets I (VDDR1), whereas heterozygosity results in lower calcitriol levels. This variant showed significant heterozygous association in 3,046 parent-affected child trios (p = 1 × 10(-5)). Further genotyping in >12,500 individuals showed that other rare loss of function CYP27B1 variants also conferred significant risk of MS, Peto odds ratio = 4.7 (95% confidence interval, 2.3-9.4; p = 5 × 10(-7)). Four known VDDR1 mutations were identified, all overtransmitted. Heterozygous parents transmitted these alleles to MS offspring 35 of 35× (p = 3 × 10(-9)). INTERPRETATION: A causative role for CYP27B1 in MS is supported; the mutations identified are known to alter function having been shown in vivo to result in rickets when 2 copies are present. CYP27B1 encodes the vitamin D-activating 1-alpha hydroxylase enzyme, and thus a role for vitamin D in MS pathogenesis is strongly implicated.

Identification of genes contributing to cardiovascular disease in overweight and obese individuals from West Virginia.

Excess weight is a known risk factor for coronary artery disease (CAD) and a large percentage of overweight and obese individuals ultimately develop CAD. The objective of this study was to identify human genes associated with CAD in a subgroup of overweight and obese individuals using population-based association methods. Logistic regression analyses were used to test the association between single nucleotide polymorphisms (SNPs) in 34 candidate genes and the CAD phenotype with age, gender, and BMI as covariates. Two SNPs in the Apolipoprotein B (Apo B) gene [rs1042031 and rs1800479], one in the Cholesterol Ester Transfer Protein (CETP) gene [rs5880], and one in the Low Density Lipoprotein Receptor (LDLR) gene [rs2569538] met the 0.01 significance level for association with CAD. Based on these findings, we conclude that variants within the CETP and Apo B genes conferred susceptibility to CAD in overweight individuals and that a variant with the LDLR gene conferred susceptibility in an obese group.

Methylation of class II transactivator gene promoter IV is not associated with susceptibility to multiple sclerosis.

BACKGROUND: Multiple sclerosis (MS) is a complex trait in which alleles at or near the class II loci HLA-DRB1 and HLA-DQB1 contribute significantly to genetic risk. The MHC class II transactivator (MHC2TA) is the master controller of expression of class II genes, and methylation of the promoter of this gene has been previously been shown to alter its function. In this study we sought to assess whether or not methylation of the MHC2TA promoter pIV could contribute to MS disease aetiology. METHODS: In DNA from peripheral blood mononuclear cells from a sample of 50 monozygotic disease discordant MS twins the MHC2TA promoter IV was sequenced and analysed by methylation specific PCR. RESULTS: No methylation or sequence variation of the MHC2TA promoter pIV was found. CONCLUSION: The results of this study cannot support the notion that methylation of the pIV promoter of MHC2TA contributes to MS disease risk, although tissue and timing specific epigenetic modifications cannot be ruled out.

Analysis of 45 candidate genes for disease modifying activity in multiple sclerosis.

Multiple sclerosis (MS) is a common inflammatory disease of the central nervous system unsurpassed for its variability in disease outcome. As little is conclusively known about MS disease mechanisms, we have selected a variety of candidate genes that may influence the prognosis of the disease based on their function. A cohort of sporadic MS cases, taken from opposite extremes of the putative distribution of long-term outcome using the most stringent clinical criteria to date, was used to determine the role of on MS disease severity. The MS cases selected represent the prognostic best 5 % (benign MS) and worst 5 % (malignant MS) of cases in terms of clinical outcome assessed by the EDSS. Genotyping the two sets of MS patients (112 benign and 51 malignant) and a replication cohort from Sardinia provided no evidence to suggest that the genes selected have any outcome modifying activity, although small effects of these genes cannot be ruled out.

Differences between stance and foot preference evident in Osprey (Pandion haliaetus) fish holding during movement.

BACKGROUND: Skateboarders, snowboarders, and surfers all show stance preferences for which foot is forward while moving. We are unaware of other animals than humans with a stance preference, perhaps excepting Osprey, who fly their caught fish beneath them in a foot-forward stance. We hypothesize there should be no difference between left foot forward, right foot back (conventional) versus right foot forward left foot back (goofy) stances or for fish holding with unilateral left or right foot. Online, publicly available, convenience images of Osprey catching fish were accessed and assessed by five independent reviewers using different Internet search engines or online photo series. Stance preference and footedness were tested using chi-square analysis. RESULTS: Stance preferences were evident with the left foot forward (conventional stance) on average 64-78% of the time (all p < 0.02). No difference in foot preference for either one-foot grabs of fish during flight or for non-flight nest/perch fish holding was evident. CONCLUSION: Flight stance of Osprey holding fish shows a lateralized preference in a proportion similar to skateboarders of surfers. We discuss stance preferences in the setting of complex movements and potential flight and survival advantages for Osprey.

Factors influencing patients' receptiveness to evidence-based recommendations during the clinical encounter.

AIM: To identify the factors that promote or interfere with evidence-based clinical decisions from the patient perspective. MATERIALS & METHODS: We developed four hypothetical scenarios with clinical decisions, such as whether to pursue testing for a chronic condition. We conducted eight focus groups to better understand the influences on individuals' decisions in the context of the scenarios. RESULTS: A patient's relationship with a physician emerged as the strongest influence on whether participants would accept or reject a physician's recommendation. Various patient characteristics and a patient's financial capacity were also important influences. CONCLUSION: Our findings point to the potential for interventions that improve communications and relationships between physicians and patients to promote evidence-based care.

Association between microchimerism and multiple sclerosis in Canadian twins.

Microchimerism, the persistence of foreign cells thought to derive from previous pregnancies, has been associated with autoimmune diseases. A maternal parent-of-origin effect in MS remains unexplained. We tested for microchimerism in monozygotic and dizygotic twin-pairs with MS. Microchimerism was associated with MS in affected females from monozygotic concordant pairs when compared to both affected (p=0.020) and unaffected (p=0.025) females in monozygotic discordant pairs. Microchimerism was increased in affected females of dizygotic discordant pairs (p=0.059). The rate of microchimerism was significantly higher in affected twins than in unaffected co-twins (p=0.0059). These observations show an association in twins between the presence of microchimerism and having MS.

Exome sequencing identifies a novel multiple sclerosis susceptibility variant in the TYK2 gene.

OBJECTIVE: To identify rare variants contributing to multiple sclerosis (MS) susceptibility in a family we have previously reported with up to 15 individuals affected across 4 generations. METHODS: We performed exome sequencing in a subset of affected individuals to identify novel variants contributing to MS risk within this unique family. The candidate variant was genotyped in a validation cohort of 2,104 MS trio families. RESULTS: Four family members with MS were sequenced and 21,583 variants were found to be shared among these individuals. Refining the variants to those with 1) a predicted loss of function and 2) present within regions of modest haplotype sharing identified 1 novel mutation (rs55762744) in the tyrosine kinase 2 (TYK2) gene. A different polymorphism within this gene has been shown to be protective in genome-wide association studies. In contrast, the TYK2 variant identified here is a novel, missense mutation and was found to be present in 10/14 (72%) cases and 28/60 (47%) of the unaffected family members. Genotyping additional 2,104 trio families showed the variant to be transmitted preferentially from heterozygous parents (transmitted 16: not transmitted 5; χ(2) = 5.76, p = 0.016). CONCLUSIONS: Rs55762744 is a rare variant of modest effect on MS risk affecting a subset of patients (0.8%). Within this pedigree, rs55762744 is common and appears to be a modifier of modest risk effect. Exome sequencing is a quick and cost-effective method and we show here the utility of sequencing a few cases from a single, unique family to identify a novel variant. The sequencing of additional family members or other families may help identify other variants important in MS.

Vitamin D metabolic pathway genes and risk of multiple sclerosis in Canadians.

BACKGROUND: Multiple sclerosis (MS) is determined by interactions between genes and environment and the influence of vitamin D adequacy has been proposed. Previous studies have shown that serum 25-hydroxyvitamin D (25(OH)D) levels are genetically influenced. Polymorphisms in vitamin D pathway genes are candidates for association with MS susceptibility. METHODS: MS patients (n=1364) and their unaffected first-degree relatives (n=1661) were ascertained through the Canadian Collaborative study. Seventy-one SNPs, across four genes [vitamin D receptor (VDR), 1-alpha-hydroxylase (CYP27B1) enzyme, vitamin D binding protein (DBP), 24-hydroxylase (CYP24)], were genotyped and tested for association with MS susceptibility using TDT in PLINK. Secondary analyses included stratification for HLA-DRB1*15 and parent of origin transmission effects. RESULTS: We found no significant association of vitamin D pathway genes with MS susceptibility after correction for multiple comparisons. However, the VDR Fok1 variant (rs2228570), selected for previously positive associations with MS susceptibility and 25(OH)D levels in MS patients showed marginally distorted transmission in DRB15-negative patients (p=0.03). There was no evidence for differential maternal versus paternal allele transmission. CONCLUSIONS: The findings fail to directly connect vitamin D metabolism genes to MS susceptibility, despite a large sample size and comprehensive gene coverage.

IGHV4-39 deletion polymorphism does not associate with risk or outcome of multiple sclerosis.

The restricted use of immunoglobulin heavy chain variable (IGHV) family 4 gene segments by clonally expanded B cells in brain lesions and cerebrospinal fluid (CSF) of multiple sclerosis (MS) patients is well documented. Specifically, the overrepresentation of gene IGHV4-39 has been highlighted in multiple studies. To investigate the role of IGHV4-39 in MS, we screened 193 MS cases, representing the extremes of clinical outcome (benign and malignant), and 187 controls for a previously reported germline deletion polymorphism containing IGHV4-39. We did not reveal a genetic association linking this polymorphism to MS risk or progression.

Variants in ST8SIA1 do not play a major role in susceptibility to multiple sclerosis in Canadian families.

Multiple sclerosis (MS) is a complex trait with a significant genetic component. Recent work has implicated the ST8SIA1 gene, encoding a ganglioside synthase, in susceptibility to the disease, perhaps with a parent-of-origin effect. In this investigation of 1318 MS patients from 756 Canadian families, we analysed the transmission of the four single nucleotide polymorphisms in ST8SIA previously shown to be associated with MS. No significant association was found in the entire sample or when stratifying by transmitting parent, indicating that this gene plays little or no role in susceptibility to MS in the Canadian population.

A genome-wide scan in forty large pedigrees with multiple sclerosis.

The epidemiology of multiple sclerosis suggests that a complex interaction of genes and environment contribute to susceptibility. To enrich for families with large genetic effects and to potentially reduce genetic heterogeneity, we screened a sample of 18,794 probands and identified forty families with four or more affected individuals. Within these 40 families, HLA DRB1*15 was present in 70% of affected individuals; the transmission disequilibrium test showed a significant excess in transmission of DRB1*15 alleles to affected individuals (47 transmitted, 19 untransmitted, chi (2) = 11.9, p = 0.00057). A 10 cM genome scan was performed and analyzed for linkage under a parametric model with heterogeneity. No excess of significant sharing was observed (HLOD > 3.3) in the parametric multipoint analysis. No region exceeded that for marker GATA8A05 with an HLOD = 1.11. Follow-up genotyping with 17 microsatellites revealed a significant two-point parametric HLOD = 3.99 at marker D4S1597. Transmission disequilibrium tests for markers in this candidate region showed no transmission distortion. A scan for variants in a gene adjacent to D4S1597, PALLD, was negative for synonymous or nonsynonymous changes. A final multipoint scan incorporating all microsatellites in the region provided an HLOD = 1.30. The inability to find significant linkage in these highly penetrant families suggests that linkage is not the optimal tool for dissecting the inheritance of MS.

The high morbidity associated with handlebar injuries in children.

BACKGROUND: Although injury prevention strategies for bicyclists have focused on legislation requiring helmet use to prevent head trauma, direct impact handlebar injuries account for a significant proportion of bicycle-related injuries. Little attention, however, has been paid to strategies that prevent direct impact handlebar injuries. We reviewed our experience with bicycle-related injuries and compared outcome for children who flipped over the handlebars to those for children who sustained direct impact from the handlebars. METHODS: We queried our prospective trauma database for all bicycle injuries from 1998 to 2003. All patients with the descriptor "handlebar" in the subtext were selected. Patients were divided into two groups: those who flipped over the handlebars (n = 160) and those who sustained direct impact from the handlebars (n = 61). We examined age, gender, helmet use, injury severity score (ISS), Glasgow Coma Score (GCS), length of stay (LOS) and the need for operation. The Student's t test was used to compare continuous variables when the data were normally distributed and the Mann-Whitney was used when the data were skewed. Chi-square analysis or Fisher's exact test was used to compare categorical data. RESULTS: There was no difference between the two groups with respect to age, gender, helmet use, ISS, and GCS. However, children who suffered from handlebar injuries were more likely to require operative intervention (19/61 versus 28/160, p = 0.04) and had a significantly longer LOS (3 days versus 1 day, p < 0.001). Children who sustained direct impact from the handlebars and required operative intervention were statistically more likely to suffer from abdominal or soft tissue injuries, while those who flipped over the handlebars were statistically more likely to suffer from facial or skeletal injuries. CONCLUSIONS: Children who suffer from direct impact of the handlebars are more likely to require operative intervention and have a longer LOS than those who flip over the handlebars. While helmet utilization by bicyclists may have reduced the number of serious head injuries, direct impact from the handlebars remains a major source of bicycle-related morbidity since nearly one third of these patients required surgery. Future injury prevention strategies for bicyclists should be aimed at reducing the incidence of direct impact handlebar-related injuries.

Effect of age on cervical spine injuries in children after motor vehicle collisions: effectiveness of restraint devices.

PURPOSE: Despite the devastating consequences of cervical spine (C-spine) injury in children after motor vehicle collisions (MVC), the factors leading to the injury and the appropriateness of protective restraints remain undefined. The authors hypothesized that age-related anatomic factors contribute to inadequate restraints and therefore increase injury severity after MVC. METHODS: Data on children (<18 years, 1997 to 2002) admitted to a level 1 pediatric trauma center were prospectively collected and retrospectively reviewed. Those with C-spine injuries caused by MVC were extracted and divided into 2 groups: young (0 to 8 years) and old (9 to 18 years). Statistical comparison was by Student's t test or Z-test, with P less than.05 accepted as significant. RESULTS: Of 5,117 trauma admissions, 94 had C-spine injuries with a mean age of 11 +/- 5 years, 66% of which were boys. Among 1,124 patients who had sustained MVC there were 27 C-spine injuries (2.4% incidence), of which, 12 were less than 8 and 15 were older than 8 years. Restraint devices were utilized at least as frequently in younger children (young, 58% v. old, 43%; not significant). However, younger children had an increased incidence of permanent cord deficit (young, 57% v. old, 13%; P <.05) and closed head injury (young, 50% v. old, 7%; P <.05) even while wearing restraint devices, suggesting that restraint devices are inadequate or improperly used in younger patients. This is supported by the increased injury severity scores of the younger group (young, 37.7 +/- 8.5 v. old, 16.5 +/- 4.6; P <.05). CONCLUSIONS: Younger children suffer more sever cervical spine injuries after motor vehicle collisions than their older counterparts, in part because of the inadequacy of currently existing restraint devices. Design modifications to current restraints, including the use of head straps, might improve outcome after MVC in younger patients.

Duodenal injuries in children: beware of child abuse.

PURPOSE: It is frequently overlooked that child abuse may result in significant intraabdominal injury, particularly to the duodenum. The authors hypothesized that a significant number of duodenal injuries in young children would be the result of nonaccidental trauma. METHODS: An 8-year (1995 through 2002) retrospective review of a pediatric level I trauma center database was performed after Institutional Review Board approval was obtained, and information regarding patients with duodenal injury was abstracted. Demographic variables, injury severity, length of stay, mortality rate, and mechanism of injury were examined. Statistical analysis was performed using descriptive statistics and Student's t test. Statistical significance was defined as P less than.05. RESULTS: Over the 8-year study period, 8,968 patients were admitted, 2,179 (24%) were less than 3 years of age. Thirty children (0.3%) suffered injury to the duodenum, with 20 hematomas and 10 perforations. Patients were overwhelmingly boys (80%), with an average age of 7.6 +/- 4.4 years and Injury Severity Score (ISS) of 14 +/- 10. No patients died. Children were injured by a variety of mechanisms, including collisions involving motor vehicles (n = 9), bicycles (n = 4), and ATVs (n = 2). However, all children less than 4 years of age (n = 8) were victims of nonaccidental trauma, 2.8% of all child abuse admissions. Three of these children suffered perforations of the duodenum. Among the entire population, those children who suffered perforations had a significantly higher ISS (23.7 +/- 7.2 v 9.6 +/- 7.3; P <.0003) and longer length of stay (27.1 +/- 15.3 v 12.6 +/- 11.7; P <.007) than those with hematomas CONCLUSIONS: Injury to the duodenum is unusual in the pediatric trauma patient but does result in significant injury severity and prolonged hospitalization. In the young child, one must maintain a high index of suspicion regarding the etiology of the injury, because a large percentage is potentially the result of child abuse.