Utilising surface-level data to explore surface, tooth, individual and family influence on the aetiology of hypomineralised second primary molars.

OBJECTIVES: Hypomineralised second primary molars (HSPM) are common developmental enamel defects. The aims of this study were to use surface-level data to explore the clustering of HSPM at four levels (family, child, tooth, surface). METHODS: This study of 172 twin pairs was nested within the Peri/postnatal Epigenetic Twin Study. HSPM was measured by standardised oral examinations at age 6 years. Multilevel logistic regression models were fitted to assess the correlation structure of surface level data and variation in HSPM. The associations between surface level risk factors and HSPM were then explored using the multilevel logistic regression model using the best fitting correlation structure. RESULTS: The prevalence of HSPM was 68 (19.8%) children, with a total of 141 (10.3%) teeth and 264 tooth surfaces (6.3%) affected. Multilevel models revealed that a hierarchical structure accounting for correlation at the family, child and tooth level best accounted for the variation in HSPM. The estimated variances from the best fitting model (Model 3) were largest at the family level (12.27, 95% CI 6.68, 22.51) compared with 5.23 at the child level and 1.93 at the tooth level. Application of regression analysis utilising this three-level correlation structure identified tooth/surface level factors in addition to the previously identified familial and individual risk factors for HSPM. CONCLUSION: In addition to familial (environmental and genetic) and unique child-level factors, the aetiology of HSPM is likely to be influenced by local tooth-level factors.

Childhood Oral Infections Associate with Adulthood Metabolic Syndrome: A Longitudinal Cohort Study.

Chronic oral infection/inflammation is cross-sectionally associated with metabolic syndrome (MetS) in adults, but there are few longitudinal studies and studies on childhood oral infections and adult MetS risk. We investigated whether childhood clinical parameters indicative of oral infection/inflammation were associated with adulthood MetS and its components. A total of 755 children aged 6, 9, and 12 y underwent a clinical oral examination in 1980 as part of the Cardiovascular Risk in Young Finns Study. Oral health measures included bleeding on probing (BOP), periodontal probing pocket depth, caries, fillings, and visible plaque. Metabolic parameters were determined at baseline and during follow-up. MetS was diagnosed (n = 588, 77.9%) in the adulthood at 21 y (in 2001), 27 y (in 2007), and 31 y (in 2011) after the oral assessment, when the participants were 27 to 43 y old. Regression analyses were adjusted for childhood age, sex, body mass index, and family income, as well as adulthood smoking and education level. In adulthood, MetS was diagnosed in 11.9% (2001), 18.7% (2007), and 20.7% (2011) of participants at the 3 follow-ups. Childhood caries and fillings were associated with increased risk of adult MetS (risk ratio [95% CI], 1.25 [0.90 to 2.45] and 1.27 [1.02 to 1.99]) and with increased systolic blood pressure (1.78 [1.01 to 4.26] and 2.48 [1.11 to 4.12]) and waist circumference (2.25 [1.02 to 4.99] and 1.56 [1.01 to 3.25]), whereas BOP and visible plaque were associated with plasma glucose (1.97 [1.08 to 3.60] and 1.88 [1.00 to 3.53]). Severity of BOP (P = 0.015) and caries (P = 0.005) and teeth with plaque (P = 0.027) were associated with number of MetS components. No such trends were seen with probing pocket depth. Childhood oral infection/inflammation was associated with adverse metabolic parameters and MetS in adulthood.

A twin study of body mass index and dental caries in childhood.

Sub-optimal nutrition and dental caries are both common with significant short and long-term implications for child health and development. We applied twin statistical methods to explore the relationship between body mass index (BMI) and dental caries. We measured BMI at 18 months and six years of age and cumulative dental caries experience at six years in 344 twin children. Dental caries in primary teeth was categorised into 'any' or 'advanced' and BMI was analysed as both a continuous and categorical variable. Statistical analyses included multiple logistic regression using generalized estimating equations and within/between-pair analyses. There was no association between BMI and 'any' dental caries experience at either time-point, neither overall nor in within/between pair analyses. However, 'advanced' dental caries at six years was associated with a within-pair difference in BMI of -0.55 kg/m2 (95% CI -1.00, -0.11, p = 0.015). A within-pair increase of 1 kg/m2 in BMI was associated with a lower within-pair risk of advanced dental caries (OR 0.68, 95% CI 0.52, 0.90, p = 0.007). These findings reveal a possible causal relationship between lower BMI and dental caries. As dental outcomes were only measured at one time point, the direction of this potentially causal relationship is unclear.

Etiology of Hypomineralized Second Primary Molars: A Prospective Twin Study.

The etiology of hypomineralized second primary molars (HSPM) is unclear, but genetic and environmental factors have been proposed. The aim of this study was to investigate the relative contribution of genes and environment to the etiology of HSPM and to identify potential environmental risk factors in a longitudinal twin cohort. Children from twin pregnancies ( N = 250) were recruited antenatally, and detailed demographic, health, and phenotypic data were collected at recruitment, 24- and 36-wk gestation, birth, and 18 mo of age. 25-Hydroxyvitamin D was quantified for mothers at 28-wk gestation and infants at birth. Dental examinations were conducted on the twins at 6 y of age to determine the presence, severity, and extent of HSPM per standardized criteria. To investigate associations of environmental risk factors with HSPM, multiple logistic regression models were fitted with generalized estimating equations to adjust for twin correlation. Within- and between-pair analyses were performed for unshared continuous variables: birthweight and birth 25-hydroxyvitamin D. Twin-twin concordance for monozygotic (MZ) and dizygotic (DZ) pairs was calculated and compared after adjusting for identified risk factors. A total of 344 twins underwent the 6-y-old dental assessment; HSPM occurred in 68 (19.8%). After adjusting for potential confounders, vitamin D levels at birth, infantile eczema, dizygosity, in vitro fertilization, socioeconomic position, and maternal smoking beyond the first trimester of pregnancy demonstrated the strongest associations with HSPM. Overall concordance for HSPM was 0.47 (95% CI, 0.32 to 0.62) with weak evidence ( P = 0.078) of higher concordance in MZ twins (0.63; 95% CI, 0.38 to 0.89) as compared with DZ twins (0.41; 95% CI, 0.24 to 0.58). After adjusting for known risk factors, there was no evidence ( P = 0.172) for an additive genetic influence. These findings suggest that shared and unshared environmental factors, such as maternal smoking later in pregnancy and infantile eczema, are important in the etiology of HSPM.

The association between higher maternal pre-pregnancy body mass index and increased birth weight, adiposity and inflammation in the newborn.

BACKGROUND: Excess adiposity and adiposity-related inflammation are known risk factors for cardiovascular disease in adults; however, little is known regarding the determinants of adiposity-related inflammation at birth. OBJECTIVES: The aim of this study was to investigate the association between maternal pre-pregnancy BMI and newborn adiposity and inflammation. METHODS: Paired maternal (28-week gestation) and infant (umbilical cord) blood samples were collected from a population-derived birth cohort (Barwon Infant Study, n = 1074). Data on maternal comorbidities and infant birth anthropomorphic measures were compiled, and infant aortic intima-media thickness was measured by trans-abdominal ultrasound. In a selected subgroup of term infants (n = 161), matched maternal and cord lipids, high-sensitivity C-reactive protein (hsCRP) and maternal soluble CD14 were measured. Analysis was completed by using pairwise correlation and linear regression. Because of their non-normal distribution, pathology blood measures were log transformed prior to analysis. RESULTS: Maternal pre-pregnancy BMI was positively associated with increased birth weight (mean difference 17.8 g per kg m-2 , 95% CI 6.6 to 28.9; p = 0.002), newborn mean skin-fold thickness (mean difference 0.1 mm per kg m-2 , 95% CI 0.0 to 0.1; p < 0.001) and cord blood hsCRP (mean difference of 4.2% increase in hsCRP per kg m-2 increase in pre-pregnancy BMI, 95% CI 0.6 to 7.7%, p = 0.02), but not cord blood soluble CD14. Inclusion of maternal hsCRP as a covariate attenuated the associations between pre-pregnancy BMI and both newborn skin-fold thickness and cord blood hsCRP. CONCLUSION: Higher maternal pre-pregnancy BMI is associated with increased newborn adiposity and inflammation. These associations may be partially mediated by maternal inflammation during pregnancy.

Dissecting Kawasaki disease: a state-of-the-art review.

Kawasaki disease (KD) is a pediatric vasculitis with coronary artery aneurysms (CAA) as its main complication. The diagnosis is based on the presence of persistent fever and clinical features including exanthema, lymphadenopathy, conjunctival injection, and changes to the mucosae and extremities. Although the etiology remains unknown, the current consensus is that it is likely caused by an (infectious) trigger initiating an abnormal immune response in genetically predisposed children. Treatment consists of high dose intravenous immunoglobulin (IVIG) and is directed at preventing the development of CAA. Unfortunately, 10-20% of all patients fail to respond to IVIG and these children need additional anti-inflammatory treatment. Coronary artery lesions are diagnosed by echocardiography in the acute and subacute phases. Both absolute arterial diameters and z-scores, adjusted for height and weight, are used as criteria for CAA. Close monitoring of CAA is important as ischemic symptoms or myocardial infarction due to thrombosis or stenosis can occur. These complications are most likely to arise in the largest, so-called giant CAA. Apart from the presence of CAA, it is unclear whether KD causes an increased cardiovascular risk due to the vasculitis itself. CONCLUSION: Many aspects of KD remain unknown, although there is growing knowledge on the etiology, treatment, and development and classification of CAA. Since children with previous KD are entering adulthood, long-term follow-up is increasingly important. What is known: • Kawasaki disease (KD) is a pediatric vasculitis with coronary artery damage as its main complication. • Although KD approaches its 50th birthday since its first description, many aspects of the disease remain poorly understood. What is new: • In recent years, multiple genetic candidate pathways involved in KD have been identified, with recently promising information about the ITPKC pathway. • As increasing numbers of KD patients are reaching adulthood, increasing information is available about the long-term consequences of coronary artery damage and broader cardiovascular risk.

Vitamin D insufficiency in the first 6 months of infancy and challenge-proven IgE-mediated food allergy at 1 year of age: a case-cohort study.

BACKGROUND: Ecological evidence suggests vitamin D insufficiency (VDI) due to lower ambient ultraviolet radiation (UVR) exposure may be a risk factor for IgE-mediated food allergy. However, there are no studies relating directly measured VDI during early infancy to subsequent challenge-proven food allergy. OBJECTIVE: To prospectively investigate the association between VDI during infancy and challenge-proven food allergy at 1 year. METHODS: In a birth cohort (n = 1074), we used a case-cohort design to compare 25-hydroxyvitamin D3 (25(OH)D3 ) levels among infants with food allergy vs a random subcohort (n = 274). The primary exposures were VDI (25(OH)D3 <50 nM) at birth and 6 months of age. Ambient UVR and time in the sun were combined to estimate UVR exposure dose. IgE-mediated food allergy status at 1 year was determined by formal challenge. Binomial regression was used to examine associations between VDI, UVR exposure dose and food allergy and investigate potential confounding. RESULTS: Within the random subcohort, VDI was present in 45% (105/233) of newborns and 24% (55/227) of infants at 6 months. Food allergy prevalence at 1 year was 7.7% (61/786), and 6.5% (53/808) were egg-allergic. There was no evidence of an association between VDI at either birth (aRR 1.25, 95% CI 0.70-2.22) or 6 months (aRR 0.93, 95% CI 0.41-2.14) and food allergy at 1 year. CONCLUSIONS: There was no evidence that VDI during the first 6 months of infancy is a risk factor for food allergy at 1 year of age. These findings primarily relate to egg allergy, and larger studies are required.

The effects of maternal anxiety during pregnancy on IGF2/H19 methylation in cord blood.

Compelling evidence suggests that maternal mental health in pregnancy can influence fetal development. The imprinted genes, insulin-like growth factor 2 (IGF2) and H19, are involved in fetal growth and each is regulated by DNA methylation. This study aimed to determine the association between maternal mental well-being during pregnancy and differentially methylated regions (DMRs) of IGF2 (DMR0) and the IGF2/H19 imprinting control region (ICR) in newborn offspring. Maternal depression, anxiety and perceived stress were assessed at 28 weeks of pregnancy in the Barwon Infant Study (n=576). DNA methylation was measured in purified cord blood mononuclear cells using the Sequenom MassArray Platform. Maternal anxiety was associated with a decrease in average ICR methylation (Δ=-2.23%; 95% CI=-3.68 to -0.77%), and across all six of the individual CpG units in anxious compared with non-anxious groups. Birth weight and sex modified the association between prenatal anxiety and infant methylation. When stratified into lower (⩽3530 g) and higher (>3530 g) birth weight groups using the median birth weight, there was a stronger association between anxiety and ICR methylation in the lower birth weight group (Δ=-3.89%; 95% CI=-6.06 to -1.72%), with no association in the higher birth weight group. When stratified by infant sex, there was a stronger association in female infants (Δ=-3.70%; 95% CI=-5.90 to -1.51%) and no association in males. All the linear regression models were adjusted for maternal age, smoking and folate intake. These findings show that maternal anxiety in pregnancy is associated with decreased IGF2/H19 ICR DNA methylation in progeny at birth, particularly in female, low birth weight neonates. ICR methylation may help link poor maternal mental health and adverse birth outcomes, but further investigation is needed.

Longitudinal investigation of adenovirus 36 seropositivity and human obesity: the Cardiovascular Risk in Young Finns Study.

BACKGROUND/OBJECTIVES: Adenovirus-36 (Adv-36) infection is associated with exaggerated adipogenesis in cell culture and the development of obesity in animal models and humans, but a causal relationship remains unproven. Our objective was to determine whether serological evidence of Adv-36 infection in childhood and/or adulthood is associated with adult obesity. SUBJECTS/METHODS: Paired plasma concentrations of Adv-36 antibodies were measured by a novel enzyme-linked immunosorbent assay in a subgroup (n=449) of the Cardiovascular Risk in Young Finns Study in childhood (mean age 11.9 years) and adulthood (mean age 41.3 years). The study group included (1) individuals who had maintained normal-weight status (2) those who became obese adults from a normal-weight status in childhood and (3) those that were overweight/obese as a child and obese as an adult. RESULTS: Mean (s.d.) time between baseline and follow-up was 29.4 (3.2) years (range 21-31 years). A total of 24.4% of individuals who were normal weight throughout life were seropositive for Adv-36 during child and/or adulthood as compared with 32.3% of those who became obese adults (P=0.11). Those who became obese in adulthood were more likely to be Adv-36 seropositive as adults compared with those who maintained normal weight (21.3% vs. 11.6%, P=0.02). This difference was mediated by a decline in Adv-36 seropositivity between child and adulthood in those maintaining normal weight. No differences were observed in body mass index across the life course, nor in waist circumference in adult life, between those who were Adv-36 seronegative or seropositive at any age. CONCLUSIONS: Individuals who gained weight across the life course were more likely to be Adv-36 seropositive in adult life than those who did not gain weight. However, analysis of change in weight status in relation to Adv-36 positivity did not support a causal role for Adv-36 in the development of obesity.

The effect of known cardiovascular risk factors on carotid-femoral pulse wave velocity in school-aged children: a population based twin study.

Childhood cardiovascular risk factors affect vascular function long before overt cardiovascular disease. Twin studies provide a unique opportunity to examine the influence of shared genetic and environmental influences on childhood cardiovascular function. We examined the relationship between birth parameters, markers of adiposity, insulin resistance, lipid profile and blood pressure and carotid-femoral pulse wave velocity (PWV), a validated non-invasive measure of arterial stiffness in a healthy cohort of school-aged twin children. PWV was performed on a population-based birth cohort of 147 twin pairs aged 7-11 years. Fasting blood samples, blood pressure and adiposity measures were collected concurrently. Mixed linear regression models were used to account for twin clustering, within- and between-twin pair associations. There were positive associations between both markers of higher adiposity, insulin resistance, elevated triglycerides and PWV, which remained significant after accounting for twin birth-set clustering. There was a positive association between both diastolic and mean arterial blood pressure and PWV in within-pair analysis in dizygotic, but not monozygotic twins, indicating genetic differences evident in dizygotic not monozygotic twins may affect these associations. Increased blood pressure, triglycerides and other metabolic markers are associated with increased PWV in school-aged twins. These results support both the genetic and environmental contribution to higher PWV, as a marker of arterial stiffness, and reiterate the importance of preventing metabolic syndrome from childhood.

FBXO11, a regulator of the TGFß pathway, is associated with severe otitis media in Western Australian children.

Otitis media (OM) is a common childhood disease characterised by middle ear inflammation following infection. Susceptibility to recurrent acute OM (rAOM) and chronic OM with effusion (COME) is highly heritable. Two murine mutants, Junbo and Jeff, spontaneously develop severe OM with similar phenotypes to human disease. Fine-mapping of these mutants identified two genes (Evi1 and Fbxo11) that interact with the transforming growth factor ß (TGFß) signalling pathway. We investigated these genes, as well as four Sma- and Mad-related (SMAD) genes of the TGFß pathway, as candidate rAOM/COME susceptibility genes in two predominantly Caucasian populations. Single-nucleotide polymorphisms (SNPs) within FBXO11 (family-based association testing Z-Score=2.61; P(best)=0.009) were associated with severe OM in family-based analysis of 434 families (561 affected individuals) from the Western Australian Family Study of OM. The FBXO11 association was replicated by directed analysis of Illumina 660W-Quad Beadchip data available for 253 cases and 866 controls (OR=1.55 (95% CI 1.28-1.89); P(best)=6.9 × 10(-6)) available within the Western Australian Pregnancy Cohort (Raine) Study. Combined primary and replication results show P(combined)=2.98 × 10(-6). Neither cohort showed an association with EVI1 variants. Family-based associations at SMAD2 (P=0.038) and SMAD4 (P=0.048) were not replicated. Together, these data provide strong evidence for FBXO11 as a susceptibility gene for severe OM.

Linkage disequilibrium analysis in the genetically isolated Norfolk Island population.

Norfolk Island is a human genetic isolate, possessing unique population characteristics that could be utilized for complex disease gene localization. Our intention was to evaluate the extent and strength of linkage disequilibrium (LD) in the Norfolk isolate by investigating markers within Xq13.3 and the NOS2A gene encoding the inducible nitric oxide synthase. A total of six microsatellite markers spanning approximately 11 Mb were assessed on chromosome Xq13.3 in a group of 56 men from Norfolk Island. Additionally, three single nucleotide polymorphisms (SNPs) localizing to the NOS2A gene were analyzed in a subset of the complex Norfolk pedigree. With the exception of two of the marker pairs, one of which is the most distantly spaced marker, all the Xq13.3 marker pairs were found to be in significant LD indicating that LD extends up to 9.5-11.5 Mb in the Norfolk Island population. Also, all SNPs studied showed significant LD in both Norfolk Islanders and Australian Caucasians, with two of the marker pairs in complete LD in the Norfolk population only. The Norfolk Island study population possesses a unique set of characteristics including founder effect, geographical isolation, exhaustive genealogical information and phenotypic data of use to cardiovascular disease risk traits. With LD extending up to 9.5-11 Mb, the Norfolk isolate should be a powerful resource for the localization of complex disease genes.

Cytosine-phosphate-guanine motifs fail to promote T-helper type 1-polarized responses in human neonatal mononuclear cells.

BACKGROUND: The T-helper type 1 (Th1) trophic properties of bacterial cytosine-phosphate-guanine (CpG) motifs have made them logical adjuvants both for the suppression of Th2-mediated allergic disease in early life and for promoting vaccine responses in neonates who have relatively immature Th1 function. However, little is known about their effects on immature immune responses in this period. OBJECTIVES: To compare the effects of CpG on adult and neonatal cellular immune responses to various stimuli. METHODS: The immune responses of mononuclear cells (MC) derived from neonates (n=25) and their mothers (n=25) were compared in vitro. These were stimulated with house dust mite (HDM), CpG B, CpG C, non-CpG oligodeoxynucleotides (ODN) or diphtheria toxoid (DT) in optimized conditions. In parallel cultures, CpGs were combined with HDM or DT antigens to assess the effect of the various ODN on these antigen-specific responses. Lymphoproliferation and cytokine responses IL-13, IFN-gamma, IL-6, IL-10, TNF-alpha) were measured for all of the cultures described above. RESULTS: Although neonates showed attenuated lymphoproliferation to CpG, the production of antigen-presenting cell-derived cytokines such as IL-6 and IL-10 and the up-regulation of major histocompatibility complex class II (HLA-DR) were detected at adult levels. T cell-derived cytokines (IL-13 and IFN-gamma) were not detectable in response to CpG alone. Most neonates also failed to produce detectable IFN-gamma to HDM or DT (unlike adults), but readily produced IL-13 to these stimuli. The addition of CpG resulted in an increase in neonatal IFN-gamma production in response to HDM (P=0.011) and a similar but non-significant trend with DT. However, rather than inhibiting Th2 IL-13 responses, the addition of CpGs was associated with a significant increase in the IL-13 responses to HDM (P=0.016) and DT (P=0.03), effects not seen in adults. CONCLUSIONS: This study provides further evidence that neonatal MC responses to CpG are functionally different from adults, and do not show clear Th1 polarization. The CpG associated increase in Th2 responses may reflect a potentiation of the normal neonatal Th2 propensity, or non-specific activation of neonatal MC.

The diagnosis and management of Kawasaki disease.

Kawasaki disease (KD) is a systemic vasculitis of childhood with a predilection for the coronary arteries. It is the predominant cause of paediatric acquired heart disease in developed countries. The aetiology of KD remains unknown and consequently there is no diagnostic test. The diagnosis is made using a constellation of clinical criteria that in isolation have poor sensitivity and specificity. Early treatment prevents overt coronary artery damage in the majority of children. The long-term effects of childhood KD on later cardiovascular health remain unknown. A recent study showed that treatment of KD in Australia is suboptimal, with late diagnosis occurring in approximately half of the cases and an unacceptably high incidence of acute cardiac involvement. These guidelines highlight the difficulties in the diagnosis of KD and offer some clues that may assist early recognition of this important paediatric disease. They also detail current treatment recommendations and the evidence on which they are based. Increased awareness of the epidemiology and spectrum of the clinical presentation of KD is essential for early recognition and optimal management.

An issue of access: delivering equitable health care for newly arrived refugee children in Australia.

Newly arrived refugees and asylum seekers are faced with many difficulties in accessing effective health care when settling in Australia. Cultural, language and financial constraints, lack of awareness of available services, and lack of health provider understanding of the complex health concerns of refugees can all contribute to limiting access to health care. Understanding the complexities of a new health care system under these circumstances and finding a regular health provider may be difficult. In some cases there may be a fundamental distrust of government services. The different levels of health entitlements by visa category and (for some) detention on arrival in Australia may further complicate the provision and use of health services for providers and patients. Children are particularly at risk of suboptimal health care due to the impact of these factors combined with the effect of resettlement stresses on parents' ability to care for their children. Unaccompanied and separated children, and those in detention experience additional challenges in accessing care. This article aims to increase awareness among health professionals caring for refugee children of the challenges faced by this group in accessing and receiving effective health care in Australia. Particular consideration is given to the issues of equity, rights of asylum seekers, communication and cultural sensitivities in health care provision, and addressing barriers to health care. The aim of the paper is to alert practitioners to the complex issues surrounding the delivery of health care to refugee children and provide realistic recommendations to guide practice.

Comprehensive health assessment for newly arrived refugee children in Australia.

Providing appropriate and responsive care to refugees from diverse backgrounds and with unique health needs is challenging. Refugee children may present with a wide range of conditions, which may be unfamiliar to health professionals in developed countries. Additionally, refugees may experience unfamiliarity with the Australian health system and distrust of authority figures and/or medical practitioners. This article provides an overview of the priority areas in health and health management for paediatric refugee patients for paediatricians as well as other relevant health care providers caring for this group. Specific issues covered include general health assessment, infectious diseases, immunization, growth and nutrition, oral health, development and disability, mental health and child protection. Comprehensive health assessment can assist in identifying children at risk of poor health and to provide them with timely and effective care, advocacy and appropriate referral.

Inducible nitric oxide synthase gene (NOS2A) haplotypes and the outcome of hepatitis C virus infection.

Inducible nitric oxide synthase (iNOS) is an important molecule involved in the host defense against infectious agents. iNOS is encoded by the NOS2A gene and well-defined haplotypes exist with respect to this gene. We examined whether these haplotypes were associated with the outcome of hepatitis C virus (HCV) infection in 619 Caucasian patients from seven European liver centres. We observed five major haplotypes: (-277A)+(-1026G)+(-1659C): haplotype 1; (-277G)+(-1026T)+(-1659C): haplotype 2; (-277G)+(-1026G)+(-1659C): haplotype 3; (-277G)+(-1026T)+(-1659T): haplotype 4; and (-277A)+(-1026T)+(-1659C): haplotype 5. Distributions of these haplotypes are comparable with those of previous studies. Homozygotes for haplotype 2 or those with haplotypes 2/4 were more likely than those with the 1/1 (wild type) combination to have self-limiting infections (odds ratios (OR)=3.43; 95% confidence intervals (95% CI): 1.10-8.0; P=0.0206 and OR=5.15; 95% CI: 1.32-14.32; P=0.0018, respectively). Conversely, carriage of haplotype 1 was associated with the lack of self-limiting disease (OR=0.48; 95% CI: 0.27-0.83; P=0.009). The effect was mainly among males (OR=0.41; 95% CI: 0.182-0.942; P=0.031 for males, and OR=0.55; 95% CI: 0.24-1.37; P=0.136 for women). Carriage of haplotype 1 was not associated with initial response (P=0.268) or sustained response (P>0.171). Combinations of haplotypes 1/4 were more likely to respond to interferon monotherapy in comparison of initial responders to nonresponders (OR=2.25; 95% CI: 1.05-5.68; P=0.0275).

Evidence for a cluster of genes on chromosome 17q11-q21 controlling susceptibility to tuberculosis and leprosy in Brazilians.

The region of conserved synteny on mouse chromosome 11/human 17q11-q21 is known to carry a susceptibility gene(s) for intramacrophage pathogens. The region is rich in candidates including NOS2A, CCL2/MCP-1, CCL3/MIP-1alpha, CCL4/MIP-1beta, CCL5/RANTES, CCR7, STAT3 and STAT5A/5B. To examine the region in man, we studied 92 multicase tuberculosis (627 individuals) and 72 multicase leprosy (372 individuals) families from Brazil. Multipoint nonparametric analysis (ALLEGRO) using 16 microsatellites shows two peaks of linkage for leprosy at D17S250 (Z(lr) score 2.34; P=0.01) and D17S1795 (Z(lr) 2.67; P=0.004) and a single peak for tuberculosis at D17S250 (Z(lr) 2.04; P=0.02). Combined analysis shows significant linkage (peak Z(lr) 3.38) at D17S250, equivalent to an allele sharing LOD score 2.48 (P=0.0004). To determine whether one or multiple genes contribute, 49 informative single nucleotide polymorphisms were typed in candidate genes. Family-based allelic association testing that was robust to family clustering demonstrated significant associations with tuberculosis susceptibility at four loci separated by intervals (NOS2A-8.4 Mb-CCL18-32.3 kb-CCL4-6.04 Mb-STAT5B) up to several Mb. Stepwise conditional logistic regression analysis using a case/pseudo-control data set showed that the four genes contributed separate main effects, consistent with a cluster of susceptibility genes across 17q11.2.