Document Detail


Methylation allelic polymorphism (MAP) in chorionic gonadotropin beta5 (CGB5) and its association with pregnancy success.
MedLine Citation:
PMID:  20962020     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
CONTEXT: Increased epigenetic variability in the placenta may have evolved in response to its role in mediating the conflicting demands of the mother and fetus. One essential guardian of early pregnancy maintenance is the placental hormone human chorionic gonadotropin (HCG).
OBJECTIVE: Among the four primate-specific duplicate HCGβ-coding genes, chorionic gonadotropin-β8 (CGB8) and chorionic gonadotropin-β5 (CGB5) jointly contribute 62-82% of the total HCGβ transcript pool. Because these genes share common features with known imprinted placenta-expressed loci, we addressed the role of epigenetic mechanisms affecting their action.
DESIGN AND SUBJECTS: Parental origin of CGB5 and CGB8 transcripts and promoter methylation patterns were addressed in trophoblastic tissues from 23 mother-offspring duos and nine mother-father-offspring trios including the following: 1) third-trimester normal delivery at term (n = 14), 2) first-trimester elective termination of uncomplicated pregnancy (n = 10), and 3) first-trimester recurrent (≥3) miscarriage (n = 8).
RESULTS: A normal uncomplicated pregnancy was characterized by balanced, biallelic expression of CGB5 and CGB8. However, in three (two recurrent miscarriage and one early elective termination of uncomplicated pregnancy) of nine genetically informative cases of CGB5, monoallelic expression of maternal alleles and hemimethylated gene promoters were identified.
CONCLUSION: Our finding may represent a novel methylation allelic polymorphism or gain of imprinting in CGB5 promoter leading to expressional silencing of paternal alleles and increasing susceptibility to pregnancy loss. Aberrant methylation patterns in placenta may result from random reprogramming defects affecting normal implantation process. Alternatively, methylation allelic polymorphism in the placenta favoring the failure of pregnancy may arise as a response to cellular stress caused by, in general, aneuploidy or conditions in placental-maternal interface.
Authors:
Liis Uusküla; Kristiina Rull; Liina Nagirnaja; Maris Laan
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-10-20
Journal Detail:
Title:  The Journal of clinical endocrinology and metabolism     Volume:  96     ISSN:  1945-7197     ISO Abbreviation:  J. Clin. Endocrinol. Metab.     Publication Date:  2011 Jan 
Date Detail:
Created Date:  2011-01-06     Completed Date:  2011-02-04     Revised Date:  2011-07-26    
Medline Journal Info:
Nlm Unique ID:  0375362     Medline TA:  J Clin Endocrinol Metab     Country:  United States    
Other Details:
Languages:  eng     Pagination:  E199-207     Citation Subset:  AIM; IM    
Affiliation:
Institute of Molecular and Cell Biology, University of Tartu, Tartu, Estonia.
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MeSH Terms
Descriptor/Qualifier:
Alleles
Chorionic Gonadotropin, beta Subunit, Human / genetics*,  metabolism
DNA Methylation / genetics*
Female
Genomic Imprinting
Humans
Placenta / metabolism*
Polymorphism, Genetic*
Pregnancy
Pregnancy Outcome
Pregnancy Trimester, First / genetics
Reverse Transcriptase Polymerase Chain Reaction
Trophoblasts / metabolism
Grant Support
ID/Acronym/Agency:
070191/Z/03/Z//Wellcome Trust; 55005617//Howard Hughes Medical Institute
Chemical
Reg. No./Substance:
0/Chorionic Gonadotropin, beta Subunit, Human
Comments/Corrections

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