Patent Application
20090104615
The invention in general terms relates to the use of epigenetic markers, especially for example in perinatal tissues, as a means for predicting the propensity for the occurrence of a phenotype in an individual. In particular, for example, the invention relates to the prediction of a propensity for obesity, altered body composition, impaired cognition, neuro-behavioural characteristics and altered cardiovascular structure and function occurring in an individual. In addition, the invention provides methods of managing the propensity for the occurrence of a phenotype (e.g. obesity) in an individual and/or a population.
The term ‘epigenetic’ is used to refer to structural changes to genes that do not alter the nucleotide sequence. Of particular relevance is methylation of specific CpG dinucleotides in gene promoters and alterations in DNA packaging arising from chemical modifications of the chromatin histone core around which DNA wraps. Such epigenetic inheritance systems can be random with respect to the environment and have been termed epimutations, or specific epigenetic changes can be induced by the environment. DNA methylation is established during early development and persists into adulthood. The inventors have, however, now for the first time obtained data linking epigenetic change, more particularly degree of gene methylation, in perinatal tissues to phenotypic characteristics in later life
Epidemiological observations previously implicated early development in the etiology of common chronic diseases, including cardiovascular disease, type-2 diabetes, obesity, metabolic syndrome, non-alcoholic steatohepatitis, impaired skeletal growth, osteoporosis, chronic obstructive airways disease including asthma, susceptibility to infection, mental illness and affective disorder, impaired cognition, cancer, impaired renal function, reproductive health and auto-immune disorders. In humans, nutritional constraint before birth has been shown to be associated with increased risk of metabolic syndrome and cardiovascular disease (Godfrey & Barker (2001); Public Health Nutrition, 4, 611-624). This causal association has been replicated in animal models of nutritional constraint during pregnancy. The phenomenon may involve adaptations to fetal physiology which predict an unfavourable postnatal environment, such as limited nutrient availability, and so improve survival. However, if nutrients are abundant, the offspring may be less able to adapt to abundant nutrient supply which can ultimately result in disease (Gluckman & Hanson (2004) Science, 305, 1733-1736). In humans, a period of nutritional constraint during pregnancy can determine the risk of developing obesity in late middle age (Ravelli et al. (1999) Am. J. Clin. Nutr. 70, 811-816).
More recently it has been observed that maternal protein-restriction during rat pregnancy induces an alteration in the methylation of the glucocortioid receptor (GR) promoter associated with altered expression of the receptor in the liver of juvenile offspring (Lillycrop et al. (2005) J. Nutr. 135(6) 1382-1386). However, this observed epigenetic change associated with changed expression does not express itself as obesity. Alteration in the methylation of the GR promoter has therefore not been considered as a relevant epigenetic change in the treatment of obesity. Further, those knowledgeable in the art have previously considered that epigenetic change is only of relevance when a direct and reciprocal change in expression in the relevant gene is also observed (as in the case of Lillycrop et al. 2005). The evaluation of epigenetic change independent of changes in gene expression has not previously been considered of value and has not been investigated. The basis of this invention is the finding that epigenetic changes in themselves are of prognostic and diagnostic value.
That degree of gene methylation can be linked to propensity for a phenotypic characteristic was first recognised by the inventors as a result of rat studies linking altered methylation of the GR promoter in rat pup adipose tissue with maternal nutritional status and pup body weight on a high fat diet. Subsequent studies reported herein have confirmed that, equally, degree of methylation of specific genes in human perinatal tissue, e.g. umbilical cord, can be linked to a variety of future phenotypic characteristics including but not limited to characteristics of body composition/growth (total and/or proportionate body fat mass, total and/or proportionate lean body mass, bone mineral content or density and height), cognitive development (intellectual quotient (IQ)), neuro-behavioural status (e.g. hyperactivity) and cardiovascular structure and function (e.g. blood pressure, aortic compliance, left ventricular mass and coronary artery diameter). For the prediction of phenotypes, epigenetic markers may be used individually and in combinations. Such use of epigenetic markers may be of particular use not only in relation to managing propensity for occurrence of undesirable phenotypic characteristics in humans, e.g. obesity, but also, for example, in enabling economic decisions on future production characteristics in agricultural animals. Such use of epigenetic markers enables the targeting of corrective strategies where propensity for an undesirable phenotypic characteristic is identified.
In its broadest aspect, the present invention thus provides a method of a predicting a phenotypic characteristic of a human or non-human animal which comprises determining the degree of an epigenetic alteration of a gene or a combination of genes in a tissue, wherein the degree of said epigenetic alteration of the gene or genes of interest correlates with propensity for said phenotypic characteristic. As indicated above, the epigenetic alteration determined may be gene methylation, either across the entirety of the gene or genes of interest or gene promoter methylation. The tissue will desirably be a tissue readily available early in life. It may desirably be a perinatal tissue sample containing genomic DNA of the individual of interest taken prior to, at, or soon after birth (generally in the case of human neonates within a month of birth), preferably for example, an umbilical cord sample, but other tissue may prove useful including in addition to adipose tissue, blood (including fetal and cord blood), placenta, chorionic villus biopsy, amniotic fluid, hair follicles, buccal smears and muscle biopsies. Preferably such tissue will be from a newborn or taken from an infant within a few weeks of birth, more preferably within a few days of birth (less than a week), although samples taken much later, e.g. within about 6 months or longer may prove useful. As indicated above, adipose tissue may be a suitable choice particularly, for example, if the phenotypic characteristic of interest is obesity and may, for example, be a perinatal adipose tissue sample or a sample taken from an older infant.
More particularly, the invention provides in one embodiment a method of predicting the propensity for obesity in an individual including the step of testing for altered methylation of the gene encoding the glucocorticoid receptor (GR). However, other genes may be preferred for methylation determination for this purpose. For example, one or more genes may be chosen for which association has been identified between degree of promoter methylation and total and/or proportionate body fat mass. The gene or genes may be selected from any of those identified in the exemplification as exhibiting such association in 9 year old children relying on umbilical cord samples, especially for example the endothelial nitric oxide synthase (NOS3) gene, the matrix metalloproteinase-2 (MMP2) gene, the phosphoinositide-3-kinase, catalytic, δ-polypeptide (P13KCD) gene and the heparan-α-glucosaminide N-acetyltransferase (HGSNAT) gene.
Preferably, for example, alteration of methylation is tested for in the adipose tissue of the individual or in an umbilical cord sample obtained at or soon after birth.
Preferably the individual is a neonate, infant, child or young adult.
The invention also provides a method of managing incidence of obesity in an individual including the steps of:
In another aspect, the invention provides a method of managing the incidence of obesity in a population including the steps of:
Further aspects of the invention will be apparent from the more detailed description and examples below and with reference to the figures, which are now detailed.
In general terms, this invention relates to a method of predicting the propensity for individuals, and populations of individuals, to develop obesity or another phenotypic characteristic using an epigenetic marker independent of changes in gene expression. The ability to predict the likely occurrence of obesity or other disorders from an early age in individuals, coupled with targeted intervention, will provide a valuable pre-emptive means of controlling the effect of the phenotype on the health of the individual at a later age. Obesity increases the incidence of diabetes, heart disease etc, therefore a reduction in the likelihood that an individual will develop obesity in later life is beneficial not only for the individual concerned but also for the community as a whole.
From this perspective the invention can also be seen to provide methods for predicting the propensity of individuals, or populations of individuals, to develop phenotypes such as diabetes and heart disease for example.
Methods of the invention can also be applied to the agricultural and domestic animal sector. Early prediction of obesity, by way of example, in farm animals (cattle, sheep, pigs, chickens, deer) would enable farmers to select and/or manage animals so as to maximise production efficiency and thereby economic returns (e.g. carcass yield of lean meat and breed or slaughter decisions). Similarly early diagnosis of predisposition to obesity would enable interventions to manage the condition and maximise animal performance in the bloodstock industries (e.g. horses) and manage obesity in companion animals (e.g. cats and dogs).
As described in more detail in Example 1, the inventors observed in rat adipose tissue that altered methylation of the glucocorticoid receptor gene, independent of any change in GR expression, provides at least a semi-permanent, if not permanent, marker that is predictive of obesity in later life. As noted above, altered methylation of the glucocorticoid receptor in the liver had previously been found to occur in neonates as a result of maternal undernutrition but was not known to be associated with obesity (Lillycrop et al. 2005, ibid.). The findings presented in Example 1 were novel and unexpected as there is no genetic change/expression link between the methylation alteration and obesity. The alteration is observable in the adipose tissue of the individual and the at least semi-permanent nature of the alteration allowed the determination of the relationship between the methylation change and the phenotype to be determined by the inventors. It is anticipated that samples for such testing, whether in animals or humans, could be taken not only from adipose tissue but also, for example, from placenta, chorionic villus biopsy, umbilical cord, blood (including fetal and cord blood), hair follicles, buccal smears and muscle biopsies, or other such readily accessible tissues.
Moreover, further data as now presented in Example 2, links degree of methylation of additional genes with indicators of obesity in humans and illustrates that determination of such epigenetic change at birth or soon after can be used to predict propensity for obesity in later life. While such studies employed umbilical cord samples taken at birth and frozen, it is to be expected that alternative perinatal tissue samples may be employed which will provide genomic DNA of the individual of interest, e.g. blood taken shortly after birth or amniotic fluid.
While the above discussion has focused principally on obesity, it is emphasised that as further illustrated by Example 2 the concept of the inventors of using epigenetic change in genes in perinatal tissues as a marker for propensity for later development of particular phenotypic characteristics extends to a wide variety of characteristics as diverse as bone mineral content and density, neuro-behavioural characteristics and IQ. For further information on specific genes for which promoter methylation status in umbilical cord has been correlated with particular phenotypic characteristics at age 9, the reader is referred to the gene tables in Example 2. Those genes for which strong correlation is noted will be favoured for use in phenotype prediction, particularly in humans.
By using microarray analysis or other methods to identify methylated promoters, methylation of combinations of different promoters may be conveniently assessed enabling propensity for a single phenotypic characteristic to be determined or propensity for multiple phenotypic characteristics to be determined simultaneously using a single tissue sample, e.g. an umbilical cord sample. A commercially available microarray may be employed such as the NimbleGen Human ChiP Epigenetic Promoter Tiling Array. However, it may be preferred to use a microarray specifically designed to detect methylation of a combination of promoters associated with propensity for one or more phenotypic characteristics. Such phenotype-specific microarrays form a further aspect of the invention. However, alternatively methylation-sensitive amplification, e.g. PCR amplification, may be carried out, particularly if the desire is to look at methylation status of a single gene or small number of genes strongly linked with one or more phenotypic characteristics. In this case, the gene or genes of interest will be amplified and the amplified nucleic acid treated with methylation-sensitive restriction enzymes, e.g. Aci1 and Hpa11, as described in more detail in Example 1. A primer and restriction enzyme kit suitable for carrying out methylation-sensitive amplification to detect methylation status of a combination of genes associated with propensity for one or more phenotypic characteristics constitutes a still further aspect of the invention.
Once the propensity for exhibiting phenotypes has been determined in an individual, management of that individual's lifestyle (diet, behaviour, exercise, etc) can be undertaken to reduce the risk of the actual occurrence of any undesirable characteristics such as obesity or low mineral bone content associated with osteoporosis.
Where a method of the invention identifies propensity for obesity in a newborn or child, then this may be used as a cue to also look at the nutritional status of the mother in view of the previously identified link between such propensity and poor maternal nutrition, and where poor maternal nutritional is found, improving the diet of the individual, e.g. by providing dietary advice and/or food supplements.
The methodology of the invention may be used to look at the occurrence of propensity for one or more phenotypic characteristics in a chosen population group and thereby used to identify external factors which contribute to the incidence of the characteristic(s), e.g. obesity, in the population of interest. In this way, information may be obtained useful in directing public health initiatives aimed at reducing the incidence of undesirable phenotypic characteristics in populations and thereby associated disorders such as diabetes, osteoporosis, sarcopenia, behavioural and mental disorders, hypertension, and cardiac problems.
The following examples illustrate the invention.
A previously developed maternal undernutrition model of fetal programming was utilized in this study (Vickers et al, 2000, American Journal of Physiology 279:E83-E87). Virgin Wistar rats (age 100±5 days) were time mated using a rat estrous cycle monitor to assess the stage of estrous of the animals prior to introducing the male. After confirmation of mating, rats were housed individually in standard rat cages with free access to water. All rats were kept in the same room with a constant temperature maintained at 25° C. and a 12-h light: 12-h darkness cycle. Animals were assigned to one of two nutritional groups: a) undernutrition (30% of ad-libitum) of a standard diet throughout gestation (UN group), b) standard diet ad-libitum throughout gestation (AD group). Food intake and maternal weights were recorded daily until the end of pregnancy. After birth, pups were weighed and litter size was adjusted to 8 pups per litter to assure adequate and standardized nutrition until weaning. Pups from undernourished mothers were cross-fostered on to dams that had received AD feeding throughout pregnancy. At weaning, AD and UN offspring were weight-matched and placed on either standard rat chow or a high fat diet (HF, Research Diets #12451, 45% kcals as fat). At postnatal day 170, rats were fasted overnight and sacrificed by halothane anaesthesia followed by decapitation. Blood was collected into heparinised vacutainers and stored on ice until centrifugation and removal of supernatant for analysis. Tissues, including retroperitoneal fat, were dissected, weighed, immediately frozen in liquid nitrogen and store at −80 until analysis. All animal work was approved by the Animal Ethics Committee of the University of Auckland.
Body composition was assessed using dual energy x-ray absorbtiometry (DEXA, Hologic, Waltham, Mass., USA).
Analysis of mRNA Expression
PPARα, PPARγ, AOX, CPT-1, lipoprotein lipase (LPL), leptin receptor (LR), glucocorticoid receptor and leptin mRNA concentrations were determined by RTPCR amplification and quantified by densitometry [Lillycrop et al. (2005)]. Briefly, total RNA was isolated from cells using TRIZOL reagent (InVitrogen), and 0.1 μg served as a template to prepare cDNA using 100 U Moloney-Murine Leukemia Virus reverse transcriptase. cDNA was amplified using primers specific to PPARα, PPARγ, AOX, CPT-1, LPL, LR, leptin and GR (Table 1). The PCR conditions in which the input cDNA was linearly proportional to the PCR product were initially established for each primer pair. One tenth of the cDNA sample was amplified for 25 cycles for the housekeeping gene ribosomal 18S and for 30 cycles for other genes. mRNA expression was normalized using the housekeeping gene ribosomal 18S RNA.
The methylation status of genes was determined using methylation-sensitive PCR as described [Lillycrop et al. (2005)]. Briefly, genomic DNA (5 μg), isolated from adipose tissue using a QIAquick PCR Purification Kit (QIAGEN, Crawley, Sussex, UK) and treated with the methylation-sensitive restriction enzymes Aci1 and HpaII as instructed by the manufacturer (New England Biolabs, Hitchin, Hertfordshire, UK). The resulting DNA was then amplified using real-time PCR (Table 1), which was performed in a total volume of 25 μL with SYBR® Green Jumpstart ready mix as described by the manufacturer (Sigma, Poole, Dorset, UK). As an internal control, the promoter region from the rat PPARγ2 gene, which contains no CpG islands and no Aci1 or HpaII recognition sites, was amplified. All CT values were normalized to the internal control.
Statistical analyses were carried out using SPSS (SPSS Inc., Chicago, USA) statistical packages. Differences between groups were determined by two-way factorial ANOVA (prenatal nutrition and postnatal diet as factors) followed by Bonferonni post-hoc analysis and data are shown as mean ±SEM.
Referring to the
Umbilical cord samples were taken from pregnancies in the University of Southampton/UK Medical Research Council Princess Anne Hospital Nutrition Study.
In 1991-2 Caucasian women aged >16 years with singleton pregnancies of <17 weeks' gestation were recruited at the Princess Anne Maternity Hospital in Southampton, UK; diabetics and those who had undergone hormonal treatment to conceive were excluded. In early (15 weeks of gestation) and late (32 weeks of gestation) pregnancy, we administered a dietary and lifestyle questionnaire to the women. Anthropometric data on the child were collected at birth and a 1-inch section of umbilical cord was collected and stored at −40° C. Gestational age was estimated from menstrual history and scan data. 559 children were followed-up at age nine months, when data on anthropometry and infant feeding were recorded. Collection and analysis of human umbilical cord samples was carried out with written informed consent from all subjects and under IRB approval from the Southampton and South West Hampshire Joint Research Ethics Committee.
When these children approached age nine years, we wrote to the parents of those still living in Southampton inviting the children to participate in a further study. Of 461 invited, 216 (47%) agreed to attend a clinic. Height was measured using a stadiometer and weight using digital scales (SECA Model No. 835). The children underwent measurements of body composition by DXA (dual energy x-ray absorptiometry; Lunar DPX-L instrument using specific paediatric software; version 4.7c, GE Corporation, Madison, Wis., USA). The instrument was calibrated every day and all scans were done with the children wearing light clothing. The short-term and long-term coefficients of variation of the instrument were 0.8% and 1.4% respectively. After a five-minute rest, systolic and diastolic blood pressures were measured three times on the left arm placed at the level of the heart whilst the child was seated. Measurements were made using a Dinamap 1846 (Critikon, UK), with manufacturer's recommended cuff sizes based on the child's mid upper arm circumference. The mean of the three measurements was used in the analysis.
Cognitive function was measured using the Wechsler Abbreviated Scale of Intelligence (WASI) (Wechsler D., Wechsler Abbreviated Scale of Intelligence. The Psychological Corporation, Sam Antonio, 1999) and psychological health was assessed with the Strengths and Difficulties Questionnaire (SDQ), which was completed by the mother (Goodman R. The Strengths and Diffculties Questionnaire: a research note. J. Child Psychol. Psychiatr. (1997) 38:581-586). The SDQ is made up of 5 subscales assessing prosocial behaviour, hyperactivity, emotional symptoms, conduct problems and peer problems.
Arterial compliance was measured by a non-invasive optical method that determines the transit time of the wave of dilatation propagating in the arterial wall, as a result of the pressure wave generated by contraction of the left ventricle. Measurement of the time taken for the wave to travel a known distance allows the velocity of the pulse wave to be calculated. The optical method has been validated against intra-arterial determinations of pressure wave velocity (1Bonner et al. Validation and use of an optical technique for the measurement of pulse wave velocity in conduit arteries. Fortschritt Berichte (1995) 107: 43-52). Pulse wave velocities were measured in two arterial segments, aorta to femoral, extending from the common carotid artery near the arch of the aorta into the femoral artery just below the inguinal ligament, and aorta to foot, extending to the posterior tibial artery. Pulse wave velocity is inversely related to the square root of the compliance of the vessel wall. High pulse wave velocity therefore indicates a stiffer arterial wall.
When pulse rate and blood pressure measurements indicated hemodynamic stability, transthoracic echocardiography (Acuson 128 XP and a 3.5 MHz phased array transducer) was performed by a single ultrasonographer with the child in the left lateral recumbent position. Two dimensional, M-mode, and Doppler echocardiograms were recorded over five consecutive cardiac cycles and measurements were made off-line. Left ventricular mass (according to American Echocardiography Society convention) and total coronary artery diameter were measured as reported previously (Jiang B, Godfrey K M, Martyn C N, Gale C R (2006). Birth weight and cardiac structure in children. Pediatrics 117, e257-e261; Gale C R, Robinson S M, Harvey N C, Javaid M K, Jiang B, Martyn C N, Godfrey K M, Cooper C, Princess Anne Hospital Study Group. (2007) Maternal vitamin D status during pregnancy and child outcomes. Eur. J. Clin. Nutr.—in press).
Genomic DNA was extracted from the umbilical cord samples. We used an existing commercially available microarray (NimbleGen Human ChIP Epigenetic Promoter Tiling Array) to measure the degree of CpG methylation of putative promoters of 24,434 genes. This analyses 5-50 kb of promoter region for the comprehensive human genome in 2 arrays, tiling regions at 110 bp intervals and using variable length probes (˜5/promoter). All annotated splice variants and alternative splice sites are represented on the NimbleGen array.
In consequence of the high cost of the arrays (£1000 per subject), our approach was to maximise insights from using 18 arrays while also obtaining essential information on reproducibility; we therefore undertook measurements on 16 subjects, randomly selected from 4 strata of IQ at age 9 years, one of whom had measurements performed in triplicate.
The intra-subject variability in median gene promoter methylation as compared with controls across ˜12,000 gene promoters for the subject with a triplet of repeat assays showed a standard deviation of 0.11, as compared with a between subjects standard deviation of 0.23. This suggests that measurement error is relatively small in comparison with the biological variability between subjects.
Our initial analyses focussed on 24 genes with established candidacy for cardiovascular and bone development (Appendix 1) and the 50 genes with greatest between subject variability in gene promoter methylation measured using the NimbleGen microarray (Appendix 2). Subsequent analyses examined 55 genes with established candidacy for neural, cellular and metabolic processes (Appendix 3). Using SPSS 12.0 for Windows we used non-parametric tests (Spearman rank correlation) to relate the degree of methylation of the gene promoters in umbilical cord to offspring phenotype at age 9 years.
For 27 of the 74 genes in our initial analyses and 32 of the 55 genes in subsequent analyses (see Table 1), we found evidence that the degree of gene promoter methylation was associated with the child's total and/or proportionate body fat mass and/or body fat distribution. The associations with total body fat mass were particularly strong for the NOS3 (endothelial nitric oxide synthase) gene (Spearman correlation coefficient r=0.66, P=0.007), the MMP2 (matrix metalloproteinase-2) gene (r=0.62, P=0.01) and the PI3KCD (phosphoinositide-3-kinase, catalytic, δ-polypeptide) gene (r=0.68, P=0.005;
In MRNA gene expression studies, both the FADS1 and FADS2 genes have also been found to be upregulated in liver from neonatal rats of undernourished mothers.
For 34 of the 74 genes in our initial analyses and 29 of the 55 genes in subsequent analyses (see Table 2), we found evidence that the degree of gene promoter methylation was associated with child's total lean body mass and/or proportionate lean mass. Such gene methylation is of interest in relation to identifying individuals who may be susceptible to, for example sarcopenia and impaired muscle function. The associations with child's total lean body mass were particularly strong for the RC3H2 gene (ring finger and CCCH-type zinc finger domains 2) (r=−0.70, P=0.004;
We found evidence that gene promoter methylation of 35 genes was associated with the child's bone mineral content (see Table 3), including the ECHDC2 (Enoyl Coenzyme A hydratase domain containing 2) gene (r=0.65; P=0.015), the MAOA (monoamine oxidase A) gene (r=0.65, P=0.006), the RXRA (retinoid X receptor, alpha) gene (r=0.68, P=0.005) and the RXRB (retinoid X receptor, beta) gene (r=0.74, P=0.002;
For 20 of the 74 genes in our initial analyses and 25 of the 55 genes in our subsequent analyses (see Table 5), we found evidence that the degree of gene promoter methylation was associated with child's IQ. The associations with full scale IQ were particularly strong for the NOX5 (NADPH oxidase, EF-hand calcium binding domain 5) gene (r=0.64, P=0.008;
Results also indicate that degree of gene promoter methylation can be used as a useful marker for neuro-behavioural disorders including, but not limited to hyperactivity, emotional problems, conduct problems, peer problems and/or total difficulties. For 48 of the 74 genes in our initial analyses and 34 of the 55 genes in our subsequent analyses (See Table 6), we found evidence that the degree of gene promoter methylation was associated with child's score on hyperactivity, emotional problems, conduct problems, peer problems and/or total difficulties scales. The associations with hyperactivity score were particularly strong for the IL8 (interleukin-8) gene (r=−0.77, P=0.002) and the ECHDC2 (Enoyl Coenzyme A hydratase domain containing 2) gene (r=−0.72, P=0.005;
Homo sapiens cDNA FLJ46698 fis, clone TRACH3013684
For 31 of the 74 genes in our initial analyses and 27 of the 55 genes in our subsequent analyses (see Table 7), we found evidence that the degree of gene promoter methylation was associated with child's systolic and/or diastolic blood pressure. Methylation of such gene promoters is therefore of interest in predicting propensity for hypertension. The associations with child's systolic blood pressure were particularly strong for the NOS3 (endothelial nitric oxide synthase) gene (r=0.68, P=0.005; see
For 25 of the 74 genes in our initial analyses and 22 of the 55 genes in our subsequent analyses (see Table 8), we found evidence that the degree of gene promoter methylation was associated with child's aorto-femoral pulse wave velocity and/or carotid artery intima media thickness. Identification of such association may enable intervention to reduce disease risk associated with circulation problems, particularly atherosclerosis. The associations with child's aorto-femoral pulse wave velocity were particularly strong for the ATP2B1 (ATPase, Ca++ transporting, plasma membrane 1 (PMCA1)) gene (r=0.68, P=0.005) and the SOD1 (superoxide dismutase) gene (r=0.82, P<0.001, see
For 7 of the 74 genes in our initial analyses and 3 of the 55 genes in our subsequent analyses (see Table 9), we found evidence that the degree of gene promoter methylation was associated with child's left ventricular mass. Determination of methylation of such genes is therefore of interest in predicting propensity for left ventricular hypertrophy. The associations were particularly strong for the KLHL5 (Kelch-like 5) gene (r=−0.67, P=0.006) and the RC3H2 (Ring finger and CCCH-type zinc finger domains 2) gene (r=−0.57, P=0.026; see
For 13 of the 74 genes in our initial analyses and 14 of the 55 genes in our subsequent analyses (see Table 10), we found evidence that the degree of gene promoter methylation was associated with child's total coronary artery diameter. Early age identification of propensity for small coronary artery clearly has important implications for combating coronary heart disease. The associations were particularly strong for the TRPC1 (Transient receptor potential cation channel, subfamily C, member 1) gene (r=−0.75, P=0.03, n=8; see
| Number | Date | Country | Kind |
|---|---|---|---|
| 546953 | May 2006 | NZ | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/GB2007/050229 | 5/2/2007 | WO | 00 | 10/30/2008 |
| Number | Date | Country | |
|---|---|---|---|
| 60919104 | Mar 2007 | US |
