Parental imprinting is an epigenetic process leading to monoallelic expression of certain genes depending on their parental origin. Imprinting diseases are characterized by growth and metabolic issues starting from birth to adulthood. They are mainly due to methylation defects in imprinting control region that drive the abnormal expression of imprinted genes. We currently lack relevant animal or cellular models to unravel the pathophysiology of growth failure in these diseases. We aimed to characterize the methylation of imprinting regions in dental pulp stem cells and during their differentiation in osteogenic cells (involved in growth regulation) to assess the interest of this cells in modeling imprinting diseases. We collected dental pulp stem cells from five controls and four patients (three with Silver-Russell syndrome and one with Beckwith-Wiedemann syndrome). Methylation analysis of imprinting control regions involved in these syndromes showed a normal profile in controls and the imprinting defect in patients. These results were maintained in dental pulp stem cells cultured under osteogenic conditions. Furthermore, we confirmed the same pattern in six other loci involved in imprinting diseases in humans. We also confirmed monoallelic expression of H19 (an imprinted gene) in controls and its biallelic expression in one patient. Extensive imprinting control regions methylation analysis shows the strong potential of dental pulp stem cells in modeling imprinting diseases, in which imprinting regions are preserved in culture and during osteogenic differentiation. This will allow to perform in vitro functional and therapeutic tests in cells derived from dental pulp stem cells and generate other cell-types.
Adult ; Animals ; DNA Methylation ; Dental Pulp ; Genomic Imprinting ; Humans ; Osteogenesis/genetics* ; Stem Cells

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*

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

OBJECTIVETo explore the genetic cause for two children with omphalocele.

METHODSThe patients were examined, and the medical history of their families was collected. Methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) was performed to detect potential mutation in the patients.

RESULTSLoss of methylation of imprinting center 2 (IC2) at the 11p15.5 region of the maternal chromosome was detected in both children.

CONCLUSIONThe two patients were diagnosed with Beckwith-Wiedemann syndrome by MS-MLPA. The loss of methylation of IC2 probably underlies the disease in both patients.

Beckwith-Wiedemann Syndrome ; genetics ; Chromosomes, Human, Pair 11 ; DNA Methylation ; Female ; Genomic Imprinting ; Humans ; Infant ; Infant, Newborn ; Male ; Multiplex Polymerase Chain Reaction

Objective: To investigate the influence of high fat diet-induced obesity (HFDIO) on the differentially methylated region (DMR) of the imprinted gene and global genome methylation of sperm DNA. METHODS: We performed bisulfite sequencing on the DMR of the imprinted gene and global genome methylation of sperm DNA in the mouse model of HFDIO. RESULTS: No statistically significant differences were found between the HFDIO model and normal control mice in MEG3-IG (93.73 vs 97.26%, P = 0.252), H19 (98.00 vs 97.83%, P = 0.920), IGF2 (97.34 vs 96.25%, P =0.166), IGF2R (1.43 vs 1.11%, P = 0.695), PEG3 (0.19 vs 0.38%, P = 0.537), MEST (0.23 vs 0.68%, P = 0.315), NNAT (0.31 vs 0.00%, P = 0.134), or SNRPN (1.88 vs 3.13%, P = 0.628). A total of 8 942 DMRs were detected across the sperm genome (P <0.05). Gene functional enrichment analysis indicated that the enriched terms with the largest numbers of genes were the metabolic process (n = 1 482), RNA synthesis (n = 779), and transcription (n = 767). CONCLUSIONS The methylation level underwent no significant change in the DMRs of the imprinted genes from the mice with HFDIO, but the CG methylation of the genes involved in the metabolic process, RNA synthesis and transcription were significantly altered.
Animals ; DNA Methylation ; Diet, High-Fat ; Genome ; Genomic Imprinting ; Insulin-Like Growth Factor II ; Male ; Mice ; Obesity ; genetics ; metabolism ; RNA ; biosynthesis ; Spermatozoa ; metabolism

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

Spermatogenesis is a process consisting of spermatogonial proliferation, spermatocytic meiosis, and spermiogenesis, and is also considered to be a process in which heterochromatins gradually aggregate and finally reach a highly condensed formation in the sperm head. Recent studies show that epigenetic regulation plays a key role in spermatogenesis. This review discusses the mechanisms of epigenetic regulation in spermatogenesis in three aspects, DNA methylation, histone modification, and noncoding RNAs. These factors are essential for spermatogenesis, fertilization, and embryogenesis by mutual regulation as well as by gene expression regulation, transposon activation, sex chromosome inactivation, and genome imprinting.
DNA Methylation ; Embryonic Development ; Epigenesis, Genetic ; physiology ; Genomic Imprinting ; Humans ; Male ; Meiosis ; Spermatogenesis ; genetics ; Spermatogonia ; cytology ; physiology

OBJECTIVETo improve the accuracy of the diagnosis of the disease on the basis of the clinical features and genetic characteristics of patients with Silver Russell syndrome (SRS).

METHODPatients diagnosed with SRS by Price criteria in 2006 to 2011 were reviewed for their clinical manifestations, physical signs, laboratory examinations and treatments.

RESULTTwenty cases with SRS were 0.08-12.17 yr old. Fifteen were male and 5 were female. The clinical characteristics included more than 80% of cases had postnatal growth retardation 100% (20/20), craniofacial dysmorphism 100% (20/20), small for gestation age 95% (19/20), asymmetry and thinning of the face and/or limbs 90% (18/20), fifth finger clinodactyly 80% (16/20), BMI < -2 SDS 80% (16/20). Their height was obviously lagging behind in the bone age. HD SDS/average of bone retardation was 3.08. The two patients with the chief complaint of external genital abnormalities would have aggressive surgical treatment and they did not use the growth hormone (GH) treatment. Only six patients had used the GH treatment. GH treatment at a dose of 0.1 IU/(kg·d) used in 2 cases achieved a growth velocity (GV) 8 - 11 cm/yr but in another 2 cases < 5 cm/yr. In genetic study, 6 patients were found to have 11p15 low methylation, 1 had low and high methylation, 1 had duplication, no relation between clinical and methylation of 11p15 was found.

CONCLUSIONThere were great variations of clinical features in SRS characterized by small for gestation age and/or postnatal growth retardation, craniofacial dysmorphism, asymmetry of the face and/or limbs or ultrafine limbs, fifth finger clinodactyly. Severely low BMI was seen and height was obviously lagging behind in the bone age. The findings of laboratory tests and imaging of SRS were not specific. Some of SRS had 11p15 imprinting defects. The treatment of SRS is mainly symptomatic.

Abnormalities, Multiple ; diagnosis ; genetics ; Adolescent ; Body Height ; Bone Density ; Child ; Child, Preschool ; Chromosomes, Human, Pair 11 ; genetics ; DNA Methylation ; Female ; Genetic Association Studies ; Genomic Imprinting ; Growth Disorders ; diagnosis ; genetics ; Humans ; Infant ; Male ; Retrospective Studies ; Silver-Russell Syndrome ; diagnosis ; genetics

OBJECTIVETo study the correlation of the DNA methylation status of the imprinted gene H19 imprinting control region (ICR) with oligozoospermia and asthenozoospermia.

METHODSWe eliminated chromosomal abnormality as the cause of male infertility in the subjects by karyotype analysis and detection of Y-chromosome microdeletions, and identified 18 cases of single factor-induced oligozoospermia (sperm concentration < 15 x 10(6)/ml) and 20 cases of single factor-induced asthenozoospermia (progressively motile sperm <32%) by computer-aided sperm analysis (CASA). Then we extracted genome-wide sperm DNA, treated it with bisul- fite, subjected the target gene fragments to PCR amplification and sequencing. Lastly, we analyzed the DNA methylation status of the target genes with BIQ Analyzer and processed the data using SPSS17.0.

RESULTSThe DNA methylation level of the H19 ICR was increased significantly in the oligozoospermia patients ([9.19 +/- 2.45]%, P < 0.05), especially in the severe oligozoospermia males with sperm concentration < 3 x 10(6)/ml (P < 0.01), as compared with that of the 20 fertile control men ([0.30 +/- 0.06]%). However, no significant differences were found in the level ([0.30 +/- 0.07]%) and pattern of the DNA methylation of the H19 ICR (P = 0.62). Further analysis of the DNA methylation status of the CTCF-6 binding sites indicated that the DNA methylation degree was significant higher in the oligozoospermia men ([2.67 +/- 0.75]%) than in the fertile control ([0.05 +/- 0.03]%) or the asthenozoospermia group ([0.03 +/- 0.02]%), with no significant differences between the latter two (P = 0.35).

CONCLUSIONThe reduced DNA methylation of the H19 ICR is negatively correlated with sperm concentration but not associated with sperm motility.

Adult ; Asthenozoospermia ; genetics ; Chromosome Deletion ; Chromosomes, Human, Y ; genetics ; DNA ; genetics ; DNA Methylation ; Genomic Imprinting ; Humans ; Infertility, Male ; Karyotyping ; Male ; Oligospermia ; genetics ; RNA, Long Noncoding ; genetics ; Sex Chromosome Aberrations ; Sex Chromosome Disorders of Sex Development ; genetics ; Sperm Count ; Sperm Motility

OBJECTIVETo report on 5 patients with maternal 3-methylcrotonyl coenzyme A carboxylase deficiency (MCCD) and to confirm the clinical diagnosis through mutation analysis.

METHODSFive neonates with higher blood 3-hydroxy isovalerylcarnitine (C5-OH) concentration detected upon newborn screening with tandem mass spectrometry and their mothers were recruited. Urinary organic acids were analyzed with gas chromatography mass spectrometry. Gene mutation and protein function analysis were performed by PCR direct sequencing and PolyPhen-2 software.

RESULTSHigher blood C5-OH concentrations (5.11-21.77 μmol/L) and abnormal 3-hydroxy isovalerate and 3-methylcrotonyl glycine in urine were detected in the five asymptomatic mothers, who were diagnosed as benign MCCD. Higher C5-OH concentration was also detected in their neonates by tandem mass spectrometry, which had gradually decreased to normal levels in three neonates. Four new variations, i.e., c.ins1680A(25%), c.203C > T (p.A68V), c.572T > C (p.L191P) and c.639+5G > T were detected in the MCCC1 gene, in addition with 2 mutations [c.1406G > T (p.R469L, novel variation) and c.592C > T (p.Q198X)]. The novel variations were predicted to have affected protein structure and function.

CONCLUSIONFor neonates with higher C5-OH concentration detected upon neonatal screening, their mothers should be also tested to rule out MCCD. Mutations in MCCC1 gene are quite common.

Adult ; Amino Acid Sequence ; Base Sequence ; Carbon-Carbon Ligases ; blood ; deficiency ; genetics ; Carnitine ; analogs & derivatives ; blood ; DNA Mutational Analysis ; Female ; Genomic Imprinting ; Humans ; Infant, Newborn ; Male ; Molecular Sequence Data ; Mutation ; Neonatal Screening ; Sex Factors ; Tandem Mass Spectrometry ; Urea Cycle Disorders, Inborn ; blood ; diagnosis ; enzymology ; genetics