Re: Cytokine Storm & Vitamin D relationship?
Circulating Vitamin D (actually it's not a vitamin, it's a hormone) is impacted by Vitamin D receptors (VDR). Since vitamin D levels impact: TB, HIV, cancer, immune system, diabetes, varioius metabolic disorders, cardiovascular disease, bone density, stature, rickets, leprosy, etc., etc., any abnormalites in these receptors are often related to these diseases. The VDR is a range of polymorphisms with many possible combinations which can be related to various diseases.
One of MANY resources:
Clin Chim Acta. 2006 Sep;371(1-2):1-12. Epub 2006 Mar 6. Links
Vitamin D receptor polymorphisms and diseases.
Valdivielso JM, Fernandez E.
Laboratorio de Investigación HUAV-UDL, Hospital Universitario Arnau de Vilanova, Rovira Roure 80, 25198, Lleida, Spain.
Valdivielso@medicina.udl.es
The vitamin D endocrine system is central to the control of bone and calcium homeostasis. Thus, alterations in the vitamin D pathway lead to disturbances in mineral metabolism. Furthermore, a role for vitamin D has been suggested in other diseases, like cancer, diabetes and cardiovascular disease.
Expression and nuclear activation of the vitamin D receptor (VDR) are necessary for the effects of vitamin D. Several genetic variations have been identified in the VDR. DNA sequence variations, which occur frequently in the population, are referred to as "polymorphisms" and can have biological effects. To test whether there is a linkage between VDR polymorphisms and diseases, epidemiological studies are performed. In these studies, the presence of a variation of the gene is studied in a population of patients, and then compared to a control group. Thus, association studies are performed, and a link among gene polymorphisms and diseases can be established.
Since the discovery of VDR polymorphisms a number of papers have been published studying its role in bone biology, renal diseases, diabetes, etc. The purpose of this review is to summarize the
vast amount of information regarding vitamin D receptor polymorphisms and human diseases, and discuss its possible role as diagnostic tools.
PMID: 16563362 [PubMed - indexed for MEDLINE]
http://www.ncbi.nlm.nih.gov/pubmed/16563362
Ethnic susceptibility to some diseases are being traced to variations in VDR polymorphisms. See (among many):
Indian Journal of Human Genetics, Vol. 9, No. 2, July-Dec, 2003, pp. 51-54
Study of vitamin-D receptor (VDR) gene start codon polymorphism (Fok I) in healthy individuals from North India
H. K. Bid, R. D. Mittal
Department of Urology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow - 226014, India.
Address for correspondence: R. D. Mittal, Additional Professor, Department of Urology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow - 226014, India. E-mail:
rmittal@sgpgi.ac.in
The vitamin D receptor (VDR) gene Fok I polymorphism represents a strong positional candidate susceptibility gene for different diseases like Prostate cancer, Urolithiasis, Inflammatory bowl disease and Osteoporosis. This genetic variation has also been of great interest due to its possible association with polygenic diseases. Allelic frequencies of the F/f start codon polymorphism of VDR gene vary among populations but there is no data regarding its distribution from India. The present study was carried out to determine the normal distribution of VDR gene Fok I polymorphism by using a PCR-based restriction analysis in unrelated normal healthy individuals from North India. We obtained an allelic frequency of 71.5% and 28.5% for (F) and (f) allele and the percentage of genotypes FF, Ff and ff as 46%, 51% and 3% respectively. Our results suggest that the frequency and distribution of this polymorphism in Indian population is substantially different from other populations and ethenic groups.
(snipped)
Discussion
SNPs are scattered throughout the genome and high degree of variability makes these informative genetic markers useful for disease susceptibility.
VDR is known to regulate cell proliferation, calcium absorption from the gut, and cell differentiation and may also influence androgen and estrogen activation. The action of VDR is not only up regulated by vitamin D but also by protein kinase A, parathyroid hormone and growth factors.
Any defect in the VDR gene could modulate the metabolism of calcium thereby increasing the risk of developing different diseases e.g. osteoporosis and calcium stones. The VDR gene Fok-1 polymorphism has been widely used as a genetic marker for diseases related to calcium metabolism. In this study we have reported the distribution of VDR Fok-1 genotypes in different populations worldwide and compared with our population.
The frequency of the individual alleles varies among different ethnic or geographic populations shown in (Table 2) but allele (F) is more common than allele (f) in different populations including ours. Genotype (FF) was significant for populations in Finland, Australia and Black Pennsylvania (P<0.05). However for the rest of the populations P-values were nonsignificant. Genotype (Ff) was not significant for all the comparable populations (P>0.05) except Black Pennsylvania (P<0.05). Genotype (ff) was significantly different in all the populations except Black Pennsylvania and north Indian population when allelic frequencies (F & f) of VDR gene in different populations were compared; Finland, Australia and White Massachusetts were significantly different.
In the present analysis, variation at VDR gene was measured solely on the basis of PCR-RFLP of the basic core sequence. Due to their highly polymorphic content, SNPs constitute useful tools in population genetic studies in understanding population and ethnic variations. As there are large differences in allele frequency and distribution of genotypes of VDR (Fok I) SNP, it would be quite helpful to find out any linkage disequilibrium in individuals from other ethnic groups.
Allelic association studies are in progress with several chronic inflammatory and degenerative diseases in which VDR may be involved. In the long run, these studies may help in determining disease susceptibility and clinical management of patients.
http://www.bioline.org.br/request?hg03011
What I take away from the reading I've done recently about VDRs and Vitamin D levels, is that variables in Vitamin D utilization/availabiity has many sources: sunlight, diet, supplementation, genetics, VDR abnormalities, etc. So it's especially important that Vitamin D be considered as a factor in many diseases.
.