Network Graph Analysis of Gene-Gene Interactions in Genome-Wide Association Study Data

Most common complex traits, such as obesity, hypertension, diabetes, and cancers, are known to be associated with multiple genes, environmental factors, and their epistasis. Recently, the development of advanced genotyping technologies has allowed us to perform genome-wide association studies (GWASs). For detecting the effects of multiple genes on complex traits, many approaches have been proposed for GWASs. Multifactor dimensionality reduction (MDR) is one of the powerful and efficient methods for detecting high-order gene-gene (GxG) interactions. However, the biological interpretation of GxG interactions identified by MDR analysis is not easy. In order to aid the interpretation of MDR results, we propose a network graph analysis to elucidate the meaning of identified GxG interactions. The proposed network graph analysis consists of three steps. The first step is for performing GxG interaction analysis using MDR analysis. The second step is to draw the network graph using the MDR result. The third step is to provide biological evidence of the identified GxG interaction using external biological databases. The proposed method was applied to Korean Association Resource (KARE) data, containing 8838 individuals with 327,632 single-nucleotide polymorphisms, in order to perform GxG interaction analysis of body mass index (BMI). Our network graph analysis successfully showed that many identified GxG interactions have known biological evidence related to BMI. We expect that our network graph analysis will be helpful to interpret the biological meaning of GxG interactions.

Five-Layered Reinforcing Amniotic Membrane Transplantation for Treatment of Deep Corneal Ulcer or Perforation

PURPOSE: To evaluate the efficacy of five-layered reinforced amniotic membrane (AM) transplantation for treating deep corneal ulcer or perforation. CASE SUMMARY: We performed a five-layered reinforced AM transplant in three cases of corneal ulceration or perforation using mechanical compressed lyophilized AMs. In all cases, the perforated cornea healed with re-epithelization within 2 weeks and the ocular surface was stabilized for more than 1 year. CONCLUSIONS: Five-layered reinforced AM transplantation may be an alternative method for treating deep corneal ulcers or perforations.