Analysis of phenotype-genotype connection: the story of dissecting disease pathogenesis in genomic era in China, and beyond

Gestational diabetes mellitus screening based on the gene chip technique

AIM

The present study sought to validate the gene chip technique to screen for gestational diabetes mellitus (GDM).

METHODS

We selected 70 single-nucleotide polymorphisms (SNPs) associated with diabetes in previous studies, and SNP genotyping was performed in 130 cases (50 diabetes patients and 80 normal controls whose mean term of pregnancies are similarly 38-39 weeks). Relevant SNP patterns were established, and gene chips were designed after statistically analyzing the data. Peripheral blood samples were then collected from 24 healthy pregnant women and 24 pregnant women with GDM for gene chip analysis. The results of the gene chip method were also verified by DNA sequencing.

RESULTS

Four candidate SNPs (rs13266634, rs266729, rs3802177 and rs9300039) were obtained after genotyping. Primers were designed based on the four SNPs, and gene chips met the quality standard according to signal intensity. The genotypes of SNPs rs3802177, rs13266634 and rs266729 showed significant differences between healthy pregnant women and pregnant women with GDM, and these results were identical to those obtained with the DNA sequencing method.

CONCLUSIONS

We have demonstrated the feasibility of the gene chip technique in screening GDM and identified candidate loci with which to study this disease.

Diagnostic test evaluation by patient-outcome study in homeopathy: balancing of feasibility and validity

BACKGROUND

Signs and symptoms can be considered as diagnostic tests, updating prior odds by applying Bayes' theorem. In homeopathy, signs and symptoms guide the doctor when prescribing appropriate medicines but the powers of these indicators are largely based on common experience.

OBJECTIVE

We want to know whether it is possible to calculate the power of arguments of signs and symptoms indicating homeopathic medicines, expressed in likelihood ratios.

METHODS

An observational patient-outcome study as advocated for diagnostic test evaluation. There was no independent observation of symptoms and results. Instead, observers were extensively trained in assessing each other's cases and the process was regularly monitored.

RESULTS

A total of 4072 prescriptions for 4094 patients were recorded. The relation between six clinical symptoms and outcome was calculated. Variance between observers in assessing symptoms and results were considerable. Some indications of confirmation bias were detected by follow-up, and 48 statistically significant likelihood ratios regarding six symptoms were calculated.

CONCLUSION

A diagnostic patient-outcome study within homeopathy collecting a large amount of data is demonstrated. Results partly confirm clinical practice at a 95% confidence level. This kind of research could validate knowledge from practical experience.