For this reason we hypothesized
For this reason we hypothesized that the DHFR gene could be a potential candidate in clefting.
Our data, obtained using a family-based association approach, evidenced an association with borderline significance for the SNP rs1677693. The variant allele A at this marker seems to reduce the risk of CL/P. Something similar was evidenced by Parle-McDermott and colleagues [Parle-McDermott et al., 2007] for the carriers of a 19bp deletion in DHFR intron 1 in spina bifida case mothers. The strongest association signal was obtained in the haplotype association analysis: OR 0.64 (95% C.I. 0.47–0.86) (P value = 0.006), for the combination rs1677693(A)-rs1650723(G).
The findings reported in the present investigation led us to attribute a role in NS-CL/P onset to the enzyme coded by the DHFR gene. How the variant rs1677693 allele could reduce the risk of CL/P is a matter of speculation, because no additional information is available about the effect of the investigated polymorphism. Considering that the association level of haplotypes was higher compared to those of the insulin receptor of each single SNP, the typed SNPs were very likely not directly involved in risk variation but instead linked with untyped causative polymorphisms.
This investigation represents the first attempt until now to link the DHFR gene to the clefting aetiology, indeed, none genome-wide association study has ever proposed the region containing the DHFR gene as candidate in the onset of cleft. The discrepancy between published data and our results, can be explained by variances in genetic background among people who belong to different racial and ethnic groups [Croen et al., 1998, Vanderas, 1987], or by intrinsic limitations related to the study design. Indeed, in a multiple testing situation, such as a genome-wide association study, rejection of null hypothesis requires extremely stringent threshold of significance.
However, even if our results do not support evidence of a major role played by DHFR in NS-CL/P onset, we cannot exclude that other polymorphisms in DHFR gene or in neighbouring loci could be involved in the aetiology of the disease. Thus, in order to further explore the real role of this candidate gene in NS-CL/P, replication studies and additional investigations are needed.
Acknowledgements We are indebted to the families participating in the study for their invaluable contribution, as well as to all the personnel involved in clinical data and specimen collection. This work was supported in part by a grant from the Association Interethnos-Interplast Italy.
Introduction Beside vaccination, therapeutic strategies to combat infectious diseases have mainly targeted some unique enzymes or components of viruses, bacteria and parasites. This approved and pathogen-directed approach, while highly successful in many cases , is faced with rising resistance to individual drugs or drug classes. This is also occurring in the field of influenza virus. Influenza epidemics and pandemics continue to be a global threat to human health . Influenza therapy is currently restricted to two classes of virus-directed drugs: M2 ion channel blockers and neuraminidase inhibitors . The first class suffers from global virus resistance and neurological side effects . The alternative neuraminidase inhibitors can also induce resistance and only provides rather modest clinical outcomes . This highlights the urgent need to develop new antiviral strategies with entirely novel action principles and reduced risk for drug resistance. An alternative concept is to design new molecules to target host cell factors that are being hijacked by the virus during its replication . Host factor-directed antiviral therapy is increasingly recognized as a relevant approach to counteract viral resistance and provide broad-spectrum antiviral agents [, , ]. The study of virus-host interactions allows the identification of the mechanisms by which viral factors co-opt host cell functions and host regulatory mechanisms that influence disease progression and treatment outcome. These host factors may be potential drug targets for disease management. Host factors for influenza virus [9,10], RSV [11,12], dengue virus [13,14], and human immunodeficiency virus (HIV) [, , , ] were recognized by transcriptomic and proteomic methods, providing more detailed biochemical insights into the replication strategies of these viruses. In general, host-directed anti-infective interventions may enhance host cell responses to pathogens, target disease-causing virulence factors, or stimulate innate or adaptive immune responses . Today, different classes of anti-influenza agents are under development to target viral or cellular proteins/processes [2,9,20].