Sarah Ahmed Abstractadmin
HIGH ALTITUDE AND PREECLAMPSIA: ADAPTATION OR PROTECTION.
Sarah I Y Ahmed
Institute of Endemic Diseases, University of Khartoum
Background: Adaptive genes to low oxygen in the high altitudes of Chinese Tibet, African Ethiopian plateau, and the Andeas of America can also be protective in diseases like preeclampsia, which may result from deregulation of hypoxia pathway.
Aim: To study the genetic variants of high altitude adaptive genes in the samples of preeclampsia in compare to normal pregnancy controls as signs of acclimatization and adaptation.
Methods: Using computational tools, a total of 36 RNA-seq samples from the amniotic fluid, were retrieved from NCBI; 19 pre-eclamptic samples and 17 full-term birth samples. Variant calling pipeline was performed for the raw RNA-seq reads. FASTQ files were downloaded from the database and were aligned to the human genome build GRCh37/hg19 to identify both known and novel SNPs and indels. Results: Adaptive variants of genes that were found predominately in highlanders were also found both in normal hypoxia of pregnancy (N=52.9%) and in pathological condition of preeclampsia with no significant difference. Interestingly, higher adaptive alleles frequency were found in normal controls of pregnancy compared to cases of Preeclampsia, p value = 0.003. The mean homozygous genotype frequency for adaptive variants were even much higher in controls than in cases, P value = 0.0001. Conclusion: The high homozygosity in the controls indicates the higher ability of controls to retain beneficial variants, which can ultimately drives the natural selection of variants towards fitness, while the heterozygosity of cases reflects the higher genetic variability that associates with slow fixation rate to the adaptive variants, which results in insufficient adaptation of spiral arterioles and shallow trophoblastic invasion, resulting in reduced uteroplacental blood flow leading to placental hypoxia, which is believed to be the underlying cause of Preeclampsia.