Uniparental disomy (UPD) refers to a chromosome defect that an individual's homologous chromosome or segments are inherited from one parent. UPD can cause either aberrant patterns of genomic imprinting or homozygosity of mutations, leading to various diseases, including cancer. The mechanisms of UPD formation are diverse but largely due to the incorrect chromosome separation during cell division. UPD does not alter the number of gene copies, thus is difficult to be detected by conventional cytogenetic techniques effectively. Assisted by the new techniques such as single nucleotide polymorphism arrays, more and more UPD-related cases have been reported recently. UPD events are non-randomly distributed across cancer types, which play important role in the occurrence, development and metastasis of cancer. Here we review the research progress on the formation mechanisms, detection methods, the involved chromosomal regions and genes, and clinical significance of UPD; and also discuss the directions for future studies in this field.
Genomic Imprinting ; Humans ; Neoplasms ; genetics ; Research ; trends ; Uniparental Disomy

The overall prevalence of uniparental disomy (UPD) across all chromosomes was estimated to be around one birth in 2000. To date, more than 4170 UPD cases have been registered. UPD for chromosomes 6, 7, 11, 14, 15, and 20 can result in clinically recognizable imprinting disorders due to abnormal levels of imprinted gene expression. For other chromosomes, the clinical consequences associated with UPD are not apparent, unless when a recessive genetic disorder is unmasked by UPD or regions of homozygosity (ROH). A clinical practice guideline will assist in strengthening the precise analysis and interpretation of the clinical significance of ROH/UPD. This guideline summarizes the conception, mechanism and clinical consequences of ROH/UPD, as well as the principles for data analysis, with an aim to standardize the clinical application and data interpretation.
Gene Expression ; Genomic Imprinting ; Homozygote ; Humans ; Uniparental Disomy/genetics*

A subset of mammalian genes differ functionally between two alleles due to genomic imprinting, and seven such genes (Peg3, Usp29, APeg3, Zfp264, Zim1, Zim2, Zim3) are localized within the 500-kb genomic interval of the human and mouse genomes, constituting the Peg3 imprinted domain. This Peg3 domain shares several features with the other imprinted domains, including an evolutionarily conserved domain structure, along with transcriptional co-regulation through shared cis regulatory elements, as well as functional roles in controlling fetal growth rates and maternal-caring behaviors. The Peg3 domain also displays some unique features, including YY1-mediated regulation of transcription and imprinting; conversion and adaptation of several protein-coding members as ncRNA genes during evolution; and its close connection to human cancers through the potential tumor suppressor functions of Peg3 and Usp29. In this review, we summarize and discuss these features of the Peg3 domain.
Alleles ; Animals ; Fetal Development ; Genes, Tumor Suppressor ; Genome ; Genomic Imprinting ; Humans ; Mice ; YY1 Transcription Factor

PURPOSE: Whether parental origin of the intact X chromosome and/or the presence of Y chromosome sequences (Yseq) play a role in three-year height response to growth hormone (GH) were investigated. METHODS: Paternal (Xp) or maternal (Xm) origin of X chromosome was assessed by microsatellite marker analysis and the presence of hidden Yseq was analyzed. The first-, second-, and third-year GH response was measured as a change in height z-score (Z_Ht) in Turner syndrome (TS) patients with 45,Xp (n=10), 45,Xm (n=15), and 45,X/46,X,+mar(Y) (Xm_Yseq) (n=8). RESULTS: The mean baseline Z_Ht did not differ according to Xp or Xm origin, however the mean baseline Z_Ht was higher in the Xm_Yseq group than in Xm group, after adjusting for bone age delay and midparental Z_Ht (P=0.04). There was no difference in the height response to GH between the 3 groups. The height response to GH decreased progressively each year (P<0.001), such that the third-year increase in Z_Ht was not significant. This third-year decrease in treatment response was unaffected by Xp, Xm, and Xm_Yseq groups. Increasing GH dosage from the second to third-year of treatment positively correlated with the increase in Z_Ht (P=0.017). CONCLUSION: There was no evidence of X-linked imprinted genes and/or Yseq affecting height response to 3 years of GH therapy. Increasing GH dosages may help attenuate the decrease in third-year GH response in TS patients with 45,X and/or 46,X/+mar(Y).
Genomic Imprinting ; Growth Hormone* ; Humans ; Microsatellite Repeats ; Parents* ; Turner Syndrome* ; X Chromosome* ; Y Chromosome*

Like the body of Hominin, mind is the result of natural selection. Therefore, an evolutionary approach in the biological aspects is essential for an intrinsic understanding of mental disorders. However, the evolutionary medical approach to mental disordershas not been well researched because evolutionary psychiatry is not widely accepted, and the conceptual paradigm has not been unified. Nevertheless, some evolutionary hypotheses about some mental disorders have been proposed, including the following: 1) thesimple disease argument that mental disorder is a mere disease, 2) the genomic lag hypothesis that current genes are incompatible with evolutionary environmental changes, 3) the developmental mismatch hypothesis that brain development cannot reflect entire-information of surrounding environment, 4) the trade-off hypothesis that costs are offset by other adaptive benefits, 5) the by-product hypothesis that mental disorders are inevitable outcome of evolutionary design, 6) the cliff-edge model that the encephalizationin the Hominin caused mental disorders, 7) the inclusive fitness hypothesis that costs of individual are compensated by benefits of kinship, 8) the antagonistic polymorphism hypothesis that differential costs and benefits according to sex or age cause ofpolymorphic psychological traits 9) the heterozygote advantage hypothesis that the heterozygous genotypes have higher relative fitness, so they can persist even though homozygous genotypes cause mental disorders, and 10) a genomic imprinting hypothesis that conflicts between maternal genes and paternal genes cause mental disorders. I will summarize and compare the evolutionary hypotheses of mental disorders and present the lim itations of each hypothesis.
Brain ; Cost-Benefit Analysis ; Genomic Imprinting ; Genotype ; Heterozygote ; Hominidae ; Humans ; Mental Disorders ; Selection, Genetic

To explore whether the imprinting status of IGF-2 in the malignant epithelial ovarian tumors is different from that in benign tumors, the target sequences (DNA and RNA) which contain a polymorphism site for ApaI restriction endonuclease digestion were amplified with PCR and RT-PCR methods. Then the PCR/RT-PCR products were digested by ApaI. The IGF-2 transcriptional pattern came out from the results of endonucleases digestion. Among the 36 cases of benign epithelial ovarian tumors, 20 were heterozygous for ApaI locus and all showed genomic imprinting. While in the malignant group, 22 were heterozygous for ApaI locus but six were found to lose imprinting. Significant differences existed between the two groups (P < 0.05). Loss of imprinting of IGF-2 may serve as a marker for differentiating the malignant ovarian cancers from the benign ones. In a new field of molecular genetics, our research provides an experimental basis for genetic diagnosis and treatment of the ovarian cancers.
Cystadenocarcinoma, Serous/*genetics ; Cystadenoma/genetics ; *Genomic Imprinting ; Insulin-Like Growth Factor II/*genetics ; Ovarian Neoplasms/*genetics

OBJECTIVETo establish and improve the method of bisulfite sequencing for methylation status of imprinted genes in single human oocytes.

METHODSSingle superovulated immature human oocyte was embedded into low melting point agarose, followed by bisulfite treatment and polymerase chain reaction (PCR) amplification of the H19 and MEST genes. The PCR products were then subjected to TA cloning and sequencing to determine the methylation status.

RESULTSWith the modified methods of embedding and bisulfite treatment, we achieved a high PCR success rate of 82.46%, with the somatic cell contamination rate as low as 7.14%. The sequencing results showed no non-CpG cytosine and exact conformity to the theoretical sequences.

CONCLUSIONThe bisulfite sequencing method we used to determine the methylation status of imprinted genes at the single-cell level was highly efficient and reliable, which can serve as a foundation for the further study of the influences of human assisted reproductive technology on genomic imprinting.

DNA Methylation ; Female ; Genomic Imprinting ; genetics ; Humans ; Oocytes ; metabolism ; Polymerase Chain Reaction ; Sequence Analysis, DNA ; methods

Epigenetics comprises the modifications made in gene expressions without changing the DNA sequence itself. Significant epigenetic changes take place during spermatogenesis and fertilization and exert direct influences on embryogenesis. This article provides an overview of the latest researches on epigenetics of male germ cells and a brief discussion on the correlation of sperm with embryogenesis in four aspects: DNA methylation, histone modification, regulation of non-coding RNAs, and genomic imprinting.
Animals ; DNA Methylation ; Embryonic Development ; Epigenesis, Genetic ; Genomic Imprinting ; Histones ; metabolism ; Humans ; Male ; Spermatozoa

The connection between male infertility and abnormal methylation of imprinted genes has attracted much attention. Some imprinted genes, e.g., H19, MEG3, MEST and SNRPN, are known to be related with male infertility. Abnormal imprinted information may influence sperm concentration, motility and morphology, but the mechanism is still unclear. Sperm genomic imprinting reconstruction and erase respectively occur at the time of spermatogenesis and before embryo transfer. Many studies have shown that the probability of imprinting disorder syndrome of offspring born through assisted reproductive technology (ART) was significantly higher, leading to the worry about the safety of ART and speculation that the operation and in vitro environment may affect sperm imprinted information, which in turn may lead to imprinting diseases in the offspring. However, above connection still lacks convincing evidence. This paper has conducted a literature review of recent literature and explored the impact of abnormal methylation of imprinted genes on male fertility and the offspring.
Genomic Imprinting ; Humans ; Infertility, Male ; genetics ; Male ; Proteins ; genetics ; RNA, Long Noncoding ; genetics ; Reproductive Techniques, Assisted

Assisted reproduction technologies (ART) include controlled ovarian hyperstimulation, in vitro fertilization-embryo transfer, intracytoplasmic sperm injection, in vitro maturation of oocytes, pre-implantation genetic diagnosis, etc. They have been used for the treatment of impaired fertility but may damage the health of offspring. The ART procedures may alter the epigenetic status of these offspring and DNA methylation may be a crucial mechanism. This paper summarizes epigenetic alterations in ART embryos and offspring, and discusses the risks.
Animals ; DNA Methylation ; Embryo, Mammalian ; metabolism ; Female ; Fertilization in Vitro ; Genomic Imprinting ; Humans ; Pregnancy ; Preimplantation Diagnosis