OBJECTIVE: To investigate the X-chromosome inactivation (XCI) patterns and origin in four children with Rett syndrome (RTT), and to explore the genetic basis of their phenotypic variability. METHODS: Four pediatric RTT cases diagnosed at Northwest Women's and Children's Hospital between August 1, 2022 and October 31, 2024 were enrolled. Clinical data were collected, and whole exome sequencing (WES) and Sanger sequencing were performed on the children and their parents to identify pathogenic variants. XCI analysis and linkage studies were conducted to determine the origin of variants and assess skewed XCI. This study was approved by the Medical Ethics Committee of the Northwest Women's and Children's Hospital (Ethics No. 21-036). RESULTS: WES and Sanger sequencing revealed that the four children carried the following MECP2 (NM_001110792.2) variants. c.916C>T (p.Arg306Cys), c.842delG (p.G281Afs*20), c.763C>T (p.R255X), and c.686C>T (p.Pro229Leu). The c.916C>T variant was maternally inherited, while the other three were de novo. All four variants have been previously reported: c.916C>T, c.842delG, and c.763C>T were classified as pathogenic, whereas c.686C>T was deemed likely pathogenic. XCI analysis demonstrated skewed inactivation in child 2 and 3 and their mothers, with maternal X-chromosome recombination during gametogenesis observed in child 3. All variants were located on the maternal X chromosome. CONCLUSION Skewed XCI is a common pathogenic mechanism in MECP2-related RTT, and MECP2 variants may exhibit a maternal origin bias. Clinical evaluation should incorporate XCI status for comprehensive genetic analysis.
Child ; Humans ; Chromosomes, Human, X/genetics* ; Exome Sequencing ; Methyl-CpG-Binding Protein 2/genetics* ; Mutation ; Rett Syndrome/genetics* ; X Chromosome Inactivation/genetics*

Long non-coding RNAs (lncRNAs) reportedly function as important modulators of gene regulation and malignant processes in the development of human cancers. The lncRNA JPX is a novel molecular switch for X chromosome inactivation and differentially expressed JPX has exhibited certain clinical correlations in several cancers. Notably, JPX participates in cancer growth, metastasis, and chemoresistance, by acting as a competing endogenous RNA for microRNA, interacting with proteins, and regulating some specific signaling pathways. Moreover, JPX may serve as a potential biomarker and therapeutic target for the diagnosis, prognosis, and treatment of cancer. The present article summarizes our current understanding of the structure, expression, and function of JPX in malignant cancer processes and discusses its molecular mechanisms and potential applications in cancer biology and medicine.
Humans ; RNA, Long Noncoding/genetics* ; Neoplasms/genetics* ; MicroRNAs/genetics* ; Gene Expression Regulation ; X Chromosome Inactivation

OBJECTIVETo explore the pathogenetic mechanism for a female patient affected with hemophilia A (HA).

METHODSPotential genetic defect was detected with inverse shifting-polymerase chain reaction (IS-PCR). The pattern of X chromosome inactivation was determined with a human androgen receptor assay (HUMARA assay). G-banded karyotyping was carried out to exclude potential chromosome aberrations.

RESULTSIS-PCR showed that the defect of FVIII gene was the distal type of intron 22 inversion. The HUMARA assay showed that the X chromosome inactivation was non-random, and that the mother's X chromosome activity was lower than that of the father's X chromosome which has carried the inverted FVIII gene. No abnormalities were found with G-banded chromosomes.

CONCLUSIONThe prevalence of female HA patient may be caused by non-random inactivation of X chromosomes.

Adolescent ; Female ; Hemophilia A ; etiology ; genetics ; Humans ; Karyotyping ; Polymerase Chain Reaction ; Receptors, Androgen ; analysis ; X Chromosome Inactivation

OBJECTIVETo investigate whether the four boys with delayed motor development and intellectual disability suffer from MECP 2 duplication syndrome.

METHODBlood specimens and clinical data of four patients and mothers of patient 2 and patient 4 were collected. Genomic DNA was extracted from peripheral blood using DNA extraction kit. At first multiplex ligation-dependent probe amplification (MLPA) was employed in 4 patients, two distinct kits SALSA P036 and P070 for sub-telomere screening, and SALSA P245 for the 22 common microdeletion and microduplication syndromes. Then array-CGH analysis was carried out. Two mothers of patients were tested by array- comparative genomic hybridization (CGH) and X chromosome inactivation analysis.

RESULTAll the 4 patients presented with severe hypotonia, delayed motor development, intellectual disability and absent or limited language. Three patients manifested recurrent pneumonia in infancy except patient 2. Four patients had duplication on chromosome Xq28 with MLPA kit SALSA P245. Array-CGH identified the size of each duplication on Xq28. The precise size of each duplication was different in the four patients: patient 1, 14.931 Mb, patient 2, 0.393 Mb, patient 3, 0.482 Mb and patient 4, 0.299 Mb. To compare Xq28 duplications with UCSC database (http://genome.ucsc.edu/) revealed that each duplication harbors the MECP 2 and HCFC 1 gene. Mothers of patient 2 and patient 4 also carried microduplication on Xq28. X chromosome inactivation analysis demonstrated completely skewed inactivation (0: 100) and it is the inactive allele that passed on to the patients.

CONCLUSIONFor patients that present with delayed motor development, intellectual disability, hypotonia, absent or limited language and recurrent infection, combination of MLPA and array- CGH is effective and specific diagnostic methods of MECP 2 duplication syndrome.

Chromosomes, Human, X ; genetics ; Comparative Genomic Hybridization ; Gene Duplication ; Humans ; Male ; Mental Retardation, X-Linked ; diagnosis ; genetics ; Methyl-CpG-Binding Protein 2 ; genetics ; Multiplex Polymerase Chain Reaction ; X Chromosome Inactivation

OBJECTIVETo explore the frequencies of heterozygosity in X-linked G6PD, P55, BTK, and FHL-1 gene exonic polymorphic loci among Chinese females and the value of determination of hematopoietic clonality by detection of these X-chromosome exonic polymorphisms based on X-chromosome inactivation patterns (XCIP)-transcription-based clonality assays (TCA).

METHODSGenomic DNA was extracted from peripheral blood of 446 Chinese healthy females. Allele-specific PCR (ASPCR) or PCR-restriction enzyme digestion method was applied for detecting G6PD, P55, BTK and FHL-1 polymorphisms. Those heterozygotic loci were used as markers to examine the hematopoietic clonality of bone marrow mononuclear cells by TCA from essential thrombocythemia (ET) patients with JAK2V617F mutation and myelodysplastic syndrome (MDS) patients with abnormal karyotype.

RESULTSAmong the total 446 genomic DNA samples, the frequencies of heterozygosity in G6PD, P55, BTK and FHL-1 loci were 12.8%, 29.4%, 52.0% and 46.4%, respectively. About 81.4% of females were heterozygous at one or more loci. All 10 ET patients with JAK2V617F mutation and 2 MDS patients with abnormal karyotype, which were heterozygotic in either locus, had monoclonal/oligoclonal hematopoiesis.

CONCLUSIONClonality detection based on X chromosome inactivation patterns-transcription based clonality assays is applicable to about 80% of Chinese females.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Alleles ; Asian Continental Ancestry Group ; genetics ; Chromosomes, Human, X ; Exons ; Female ; Genes, X-Linked ; Genetic Carrier Screening ; Genetic Linkage ; Glucosephosphate Dehydrogenase ; genetics ; Hematopoiesis ; genetics ; Humans ; Middle Aged ; Polymerase Chain Reaction ; methods ; Polymorphism, Single Nucleotide ; X Chromosome Inactivation ; Young Adult

OBJECTIVERett syndrome (RTT) is a neurodevelopmental disorder occurring almost exclusively in females as sporadic cases due to de novo mutations in the methyl-CpG-binding protein 2 gene (MECP2). Familial cases of RTT are rare and are due to X-chromosomal inheritance from a carrier mother. Recently, DNA mutations in the MECP2 have been detected in approximately 84.7% of patients with RTT in China. To explain the sex-limited expression of RTT, it has been suggested that de novo X-linked mutations occur exclusively in male germ cells resulting therefore only in affected daughters. To test this hypothesis, we have analyzed the parental origin of mutations and the XCI status in 15 sporadic cases with RTT due to MECP2 molecular defects.

METHODSAllele-specific PCR was performed to amplify a fragment including the position of the mutation. The allele-specific PCR products were sequenced to determine which haplotype contained the mutation. It was then possible to determine the parent of origin by genotyping the single nucleotide polymorphism (SNP) in the parents. The degree of XCI and its direction relative to the X chromosome parent of origin were measured in DNA prepared from peripheral blood leucocytes by analyzing CAG repeat polymorphism in the androgen receptor gene (AR).

RESULTSExcept for 2 cases who had a frameshift mutation; all the remaining 13 cases had a C-->T transition mutation. Paternal origin has been determined in all cases with the C-->T transition mutation. For the two frameshift mutations, paternal origin has been determined in one case and maternal origin in the other. The frequency of male germ-line transmission in mutations is 93.3%. Except for 2 cases who were homozygotic at the AR locus, of the remaining 13 cases, 8 cases had a random XCI pattern; the other five cases had a skewed XCI pattern and they favor expression of the maternal origin allele.

CONCLUSIONDe novo mutations in sporadic RTT occur almost exclusively on the paternally derived X chromosome and that this is most probably the cause for the high female: male ratio observed in sporadic cases with RTT. Random XCI was the main XCI pattern in sporadic RTT patients. The priority inactive X chromosome was mainly of paternal origin.

Chromosome Aberrations ; Chromosomes, Human, X ; Female ; Humans ; Male ; Methyl-CpG-Binding Protein 2 ; genetics ; Mutation ; Polymorphism, Single Nucleotide ; Rett Syndrome ; genetics ; X Chromosome Inactivation

Carcinoma, Small Cell ; genetics ; pathology ; Carcinoma, Transitional Cell ; genetics ; pathology ; Clone Cells ; DNA, Neoplasm ; genetics ; Humans ; Loss of Heterozygosity ; Lymphatic Metastasis ; Microsatellite Repeats ; Urinary Bladder Neoplasms ; genetics ; pathology ; X Chromosome Inactivation

OBJECTIVETo observe the relationship between skewed X-chromosomal inactivation (SXCI) and development of lung cancer in females.

METHODSDNA was isolated from peripheral blood cells from patients with primary lung cancer (n = 148) and control subjects (n =289). Exon 1 of androgen receptor ( AR) gene was amplified, with its products from different alleles resolved on denaturing polyacrylamide gels and visualized by silver staining. The corrected ratio (CR) between products from different AR alleles before and after Hpa II pretreatment was calculated. All statistical tests were two-sided.

RESULTSWith CR> or = 10 adopted as the criterion, SXCI was found more frequently in the younger patients ( C50 years; 7. 9%) than in the controls of the same age group (1. 2% ; P = 0. 046). The SXCI frequency, however, were not significantly different between the old patients ( > 50 years; 4. 5% ) and the controls of the same age group (5. 4% ; P =0. 488). Whether taking CR> or =3 or CR> or =10 as the criteria, the average ages of the patients with SXCI were more than 10 years younger than those without SXCI (P < 0. 05).

CONCLUSIONSXCI in blood cells is associated with early development of lung cancer in females.

Adult ; Age Factors ; Aged ; Alleles ; Chromosomes, Human, X ; genetics ; DNA ; genetics ; metabolism ; Deoxyribonuclease HpaII ; metabolism ; Exons ; Female ; Genetic Predisposition to Disease ; Humans ; Lung Neoplasms ; blood ; genetics ; pathology ; Middle Aged ; Polymerase Chain Reaction ; Receptors, Androgen ; genetics ; X Chromosome Inactivation

OBJECTIVETo study the clonality of polygonal cells and surface cuboidal cells in the so-called pulmonary sclerosing hemangioma (PSH).

METHODS17 female surgically resected PSH were found. The polygonal cells and surface cuboidal cells of the 17 PSH cases were microdissected from routine hematoxylin and eosin-stained sections. Genomic DNA was extracted, pretreated through incubation with methylation-sensitive restrictive endonuclease HhaI or HpaII, and amplified by nested polymerase chain reaction for X chromosome-linked androgen receptor (AR) and phosphoglycerate kinase (PGK) genes. The length polymorphism of AR gene was demonstrated by denaturing polyacrylamide gel electrophoresis and silver staining. The PGK gene products were treated with Bst XI and resolved on agarose gel.

RESULTSAmongst the 17 female cases of PSH, 15 samples were successfully amplified for AR and PGK genes. The rates of polymorphism were 53% (8/15) and 27% (4/15) for AR and PGK genes respectively. Polygonal cells and surface cuboidal cells of 10 cases which were suitable for clonality study, showed the same loss of alleles (clonality ratio = 0) or unbalanced methylation pattern (clonality ratio < 0.25).

CONCLUSIONSThe polygonal cells and surface cuboidal cells in PSH demonstrate patterns of monoclonal proliferation, indicating that both represent true neoplastic cells.

Chromosomes, Human, X ; genetics ; DNA, Neoplasm ; genetics ; Female ; Humans ; Male ; Phosphoglycerate Kinase ; genetics ; Polymerase Chain Reaction ; Polymorphism, Genetic ; Pulmonary Sclerosing Hemangioma ; genetics ; pathology ; Receptors, Androgen ; genetics ; X Chromosome Inactivation

OBJECTIVETo study the clonality of palmar fibromatosis by molecular genetic analysis of X chromosome inactivation pattern at a polymorphic site of human androgen receptor gene (HUMARA).

METHODSTwelve female cases of palmar fibromatosis were enrolled into this study. Hematoxylin and eosin-stained sections of paraffin-embedded, formalin-fixed tissues were microdissected by laser capture microdissection technology in order to obtain the proliferative spindle cells. Tumor cells isolated from rectal adenocarcinoma in a female patient were used as positive control. The genomic DNAs were extracted with phenol and chloroform, digested with methylation-sensitive restriction endonuclease HpaII, and amplified by polymerase chain reaction (PCR) using primers targeted to a highly polymorphic short tandem repeat of HUMARA. The amplimers were separated on vertical 8% non-denaturing polyacrylamide gels and the patterns were visualized with ethidium bromide stain.

RESULTSThe methodology for clonality analysis was validated in the positive control using rectal adenocarcinoma cells. Among the 12 cases studied, PCR amplification failed in 3 samples and 1 sample showed homozygosity which was not suitable for further analysis. Eight samples were successfully amplified and showed a random X chromosome inactivation pattern, suggesting polyclonality in these lesions.

CONCLUSIONSPalmar fibromatosis is a polyclonal condition and should be considered as a form of non-neoplasmic fibroblastic proliferation.

Actins ; metabolism ; Adolescent ; Adult ; Aged ; Child ; Chromosomes, Human, X ; Clone Cells ; metabolism ; pathology ; Dupuytren Contracture ; genetics ; metabolism ; pathology ; Female ; Humans ; Middle Aged ; Polymerase Chain Reaction ; Receptors, Androgen ; genetics ; metabolism ; X Chromosome Inactivation