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  1. Fulltext Turner syndrome with ring x chromosome: do they have a distinct phenotype?
    Lee, Yee Lin, Salwati Shuib, Wu, Loo Ling
    International Medical Journal Malaysia, 2018;17(3):99-102.
    MyJurnal
    In contrast to classic Turner syndrome, Turner patients with ring X chromosome are associated with distinct dysmorphism and are likely to be mentally impaired. Four Turner patients with ring X chromosome were examined for phenotypic features of Turner syndrome and additional dysmorphism. Both patients 1 and 2 are twins with normal intelligence whereas patients 3 and 4 have mental impairment. With the exception of patient 4, the other three patients only have few Turner characteristics. None of the patients have the distinctive dysmorphism previously reported in Turner syndrome with ring X chromosome. Both twins developed spontaneous puberty. Patients 3 and 4 however had no spontaneous puberty. We postulate that this variation may be related to the ring size, the proportion of 45,X and ring X chromosome in cell lines of various body tissues as well as the ability of these rings to be inactivated as a result of lyonisation.
    Matched MeSH terms: X Chromosome; X Chromosome Inactivation
  2. Primary infertility in a phenotypic male with 46XX chromosomal constitution
    Tan TT, Khalid BA
    Postgrad Med J, 1993 Apr;69(810):315-7.
    PMID: 8321801
    The case of a 32 year old male with normal male adrenarchal hair pattern, bilateral gynaecomastia, a small phallus, hypospadias and bilateral poorly developed testes presenting with primary infertility secondary to azoospermia and a pelvic cyst is described. Repeated chromosomal analysis showed 46XX chromosomal constitution. Laparotomy revealed a simple cyst between the urinary bladder and the rectum. XX male syndrome is a rare cause of male infertility. The majority of cases is due to interchange of a fragment of the short arm of the Y chromosome containing the region that encodes the testes determining factor with the X chromosome. The presence of a simple cyst in the anatomical location of the uterus to our knowledge has not been reported in the literature.
    Matched MeSH terms: X Chromosome*
  3. Fulltext Supernumerary chromosomes in mosaic Turner syndrome
    Thong MK, Manonmani V, Norlasiah IS
    Med J Malaysia, 1996 Dec;51(4):487-90.
    PMID: 10968041
    The finding of a supernumerary or marker chromosome in a karyotype poses difficulty in genetic counselling. The true incidence and significance of this chromosomal aberration is unknown in Malaysia. We report two patients who presented with supernumerary chromosomes in mosaic Turner syndrome.
    Matched MeSH terms: X Chromosome/genetics
  4. A female Norway rat, Rattus norvegicus, with X0 sex chromosome constitution
    Yong HS, Dhaliwal SS, Teh KL
    Naturwissenschaften, 1989 Aug;76(8):387-8.
    PMID: 2779669
    Matched MeSH terms: Sex Chromosomes*; X Chromosome*
  5. Genetics and polymorphism of a sex-linked gene in the grasshopper, Oxya japonica japonica (Orthoptera: Acrididae: Oxyinae)
    Chan KL, Yushayati Y, Guaneswaran P
    Biochem Genet, 1991 Apr;29(3-4):203-6.
    PMID: 1830472
    Matched MeSH terms: X Chromosome*
  6. Fulltext X-treme loss of sequence diversity linked to neo-X chromosomes in filarial nematodes
    Mattick J, Libro S, Bromley R, Chaicumpa W, Chung M, Cook D, et al.
    PLoS Negl Trop Dis, 2021 Oct;15(10):e0009838.
    PMID: 34705823 DOI: 10.1371/journal.pntd.0009838
    The sequence diversity of natural and laboratory populations of Brugia pahangi and Brugia malayi was assessed with Illumina resequencing followed by mapping in order to identify single nucleotide variants and insertions/deletions. In natural and laboratory Brugia populations, there is a lack of sequence diversity on chromosome X relative to the autosomes (πX/πA = 0.2), which is lower than the expected (πX/πA = 0.75). A reduction in diversity is also observed in other filarial nematodes with neo-X chromosome fusions in the genera Onchocerca and Wuchereria, but not those without neo-X chromosome fusions in the genera Loa and Dirofilaria. In the species with neo-X chromosome fusions, chromosome X is abnormally large, containing a third of the genetic material such that a sizable portion of the genome is lacking sequence diversity. Such profound differences in genetic diversity can be consequential, having been associated with drug resistance and adaptability, with the potential to affect filarial eradication.
    Matched MeSH terms: X Chromosome/genetics*
  7. Fulltext A case report of Goltz syndrome: a newborn with digital anomalies and skin lesions
    Lee, Von Yen, Leow, Poy Lee
    Malaysian Journal of Paediatrics and Child Health, 2016;22(101):0-0.
    MyJurnal
    Goltz syndrome or Focal Dermal Hypoplasia (FDH) is an uncommon genetically inherited disorder characterized by distinctive skin abnormalities and a wide variety of multisystem defects which was first described by Goltz (an American dermatologist) in 1962. About 200- 300 cases have been reported worldwide. FDH can be inherited in an X-linked dominant manner with in-utero lethality in males. Majority of the cases are sporadic with new mutations arising in the embryo and not inherited from a parent. Approximately 10% of cases occur in males; postzygotic somatic mosaicism accounts for the findings in these affected males. FDH is caused by abnormalities or mutations at the PORCN gene in the X chromosome. We report a case of FDH with characteristic skin lesions as well as multiple digital anomalies - oligodactyly, syndactyly and ectrodactyly.(Copied from article)
    Matched MeSH terms: X Chromosome
  8. Fulltext Female chromosome X mosaicism is age-related and preferentially affects the inactivated X chromosome
    Machiela MJ, Zhou W, Karlins E, Sampson JN, Freedman ND, Yang Q, et al.
    Nat Commun, 2016 06 13;7:11843.
    PMID: 27291797 DOI: 10.1038/ncomms11843
    To investigate large structural clonal mosaicism of chromosome X, we analysed the SNP microarray intensity data of 38,303 women from cancer genome-wide association studies (20,878 cases and 17,425 controls) and detected 124 mosaic X events >2 Mb in 97 (0.25%) women. Here we show rates for X-chromosome mosaicism are four times higher than mean autosomal rates; X mosaic events more often include the entire chromosome and participants with X events more likely harbour autosomal mosaic events. X mosaicism frequency increases with age (0.11% in 50-year olds; 0.45% in 75-year olds), as reported for Y and autosomes. Methylation array analyses of 33 women with X mosaicism indicate events preferentially involve the inactive X chromosome. Our results provide further evidence that the sex chromosomes undergo mosaic events more frequently than autosomes, which could have implications for understanding the underlying mechanisms of mosaic events and their possible contribution to risk for chronic diseases.
    Matched MeSH terms: X Chromosome Inactivation/genetics*
  9. Clinical patterns of X linked agammaglobulinemia in Malaysian children
    Noh LM, Ismail Z, Zainudin BM, Low SM, Azizi BH, Noah RM, et al.
    Acta Paediatr Jpn, 1995 Jun;37(3):331-5.
    PMID: 7645382
    X linked agammaglobulinemia (XLA) is rarely reported from developing countries especially from South East Asia. It appears that X linked agammaglobulinemia is less common in certain ethnic groups. It is very uncommon in black people in USA and South Africa. In multiracial Malaysia we have documented five XLA in Malays and Indians but not in the Chinese that constitute about 31% of the population. First degree relatives afflicted with XLA or other primary immunodeficiencies occurred more often in our study. All showed lung involvement although the etiologic organisms involved were atypical, being Gram negative.
    Matched MeSH terms: X Chromosome*
  10. Fulltext OFD1 is mutated in X-linked Joubert syndrome and interacts with LCA5-encoded lebercilin
    Coene KL, Roepman R, Doherty D, Afroze B, Kroes HY, Letteboer SJ, et al.
    Am J Hum Genet, 2009 Oct;85(4):465-81.
    PMID: 19800048 DOI: 10.1016/j.ajhg.2009.09.002
    We ascertained a multi-generation Malaysian family with Joubert syndrome (JS). The presence of asymptomatic obligate carrier females suggested an X-linked recessive inheritance pattern. Affected males presented with mental retardation accompanied by postaxial polydactyly and retinitis pigmentosa. Brain MRIs showed the presence of a "molar tooth sign," which classifies this syndrome as classic JS with retinal involvement. Linkage analysis showed linkage to Xpter-Xp22.2 and a maximum LOD score of 2.06 for marker DXS8022. Mutation analysis revealed a frameshift mutation, p.K948NfsX8, in exon 21 of OFD1. In an isolated male with JS, a second frameshift mutation, p.E923KfsX3, in the same exon was identified. OFD1 has previously been associated with oral-facial-digital type 1 (OFD1) syndrome, a male-lethal X-linked dominant condition, and with X-linked recessive Simpson-Golabi-Behmel syndrome type 2 (SGBS2). In a yeast two-hybrid screen of a retinal cDNA library, we identified OFD1 as an interacting partner of the LCA5-encoded ciliary protein lebercilin. We show that X-linked recessive mutations in OFD1 reduce, but do not eliminate, the interaction with lebercilin, whereas X-linked dominant OFD1 mutations completely abolish binding to lebercilin. In addition, recessive mutations in OFD1 did not affect the pericentriolar localization of the recombinant protein in hTERT-RPE1 cells, whereas this localization was lost for dominant mutations. These findings offer a molecular explanation for the phenotypic spectrum observed for OFD1 mutations; this spectrum now includes OFD1 syndrome, SGBS2, and JS.
    Matched MeSH terms: X Chromosome*
  11. Fulltext Finding the factors of reduced genetic diversity on X chromosomes of Macaca fascicularis: male-driven evolution, demography, and natural selection
    Osada N, Nakagome S, Mano S, Kameoka Y, Takahashi I, Terao K
    Genetics, 2013 Nov;195(3):1027-35.
    PMID: 24026095 DOI: 10.1534/genetics.113.156703
    The ratio of genetic diversity on X chromosomes relative to autosomes in organisms with XX/XY sex chromosomes could provide fundamental insight into the process of genome evolution. Here we report this ratio for 24 cynomolgus monkeys (Macaca fascicularis) originating in Indonesia, Malaysia, and the Philippines. The average X/A diversity ratios in these samples was 0.34 and 0.20 in the Indonesian-Malaysian and Philippine populations, respectively, considerably lower than the null expectation of 0.75. A Philippine population supposed to derive from an ancestral population by founding events showed a significantly lower ratio than the parental population, suggesting a demographic effect for the reduction. Taking sex-specific mutation rate bias and demographic effect into account, expected X/A diversity ratios generated by computer simulations roughly agreed with the observed data in the intergenic regions. In contrast, silent sites in genic regions on X chromosomes showed strong reduction in genetic diversity and the observed X/A diversity ratio in the genic regions cannot be explained by mutation rate bias and demography, indicating that natural selection also reduces the level of polymorphism near genes. Whole-genome analysis of a female cynomolgus monkey also supported the notion of stronger reduction of genetic diversity near genes on the X chromosome.
    Matched MeSH terms: X Chromosome/genetics*
  12. Fulltext Exploring Two Protocols of FISH Using Cytocell SYT-SSX Probe on Formalin Fixed Paraffin Embedded Tissue Sections
    Yajid AI, Mohd Nafi SN, Salehan NA, Tuan Sharif SE
    Asian Pac J Cancer Prev, 2020 May 01;21(5):1241-1245.
    PMID: 32458628 DOI: 10.31557/APJCP.2020.21.5.1241
    BACKGROUND: Chromosomal translocation t(X;18)(p11.2;q11.2) is the cytogenetic hallmark of synovial sarcoma and have been identified as an alternative diagnostic strategy in differentiating synovial sarcoma from other histologic mimics. This study was carried out to test the efficacy of two FISH protocols using the SYT-SSX break apart probe from Cytocell.

    METHODOLOGY: Representative paraffin blocks of synovial sarcoma were utilized in this study. FISH study was performed on formalin-fixed paraffin embedded tissue sections using the SYT-SSX break apart probe from Cytocell, to detect two form of SYT-SSX transcript, SYT-SSX1 and SYT-SSX2. FISH protocol, including the hybridization was done following two different protocols, Cytocell FISH protocol and Optimized Dako FISH protocol.

    RESULTS: Tissue samples subjected to FISH using Cytocell FISH protocol showed the absence of signal corresponding to the probe used. Utilizing Optimized Dako FISH protocol, the two signals (red and green) corresponding to the break-apart probes was detected. These findings suggested that Optimised Dako FISH protocol is more suited for use with the tested probe on paraffin embedded tissues in comparison to Cytocell FISH protocol.

    CONCLUSION: Optimised Dako FISH protocol was noted to be more suited for detecting SYT-SSX FISH signals on paraffin embedded tissues in comparison to Cytocell FISH protocol.

    Matched MeSH terms: X Chromosome
  13. Chromosomes of gaur cross domestic cattle hybrids
    Bongso TA, Hilmi M, Sopian M, Zulkifli S
    Res Vet Sci, 1988 Mar;44(2):251-4.
    PMID: 3387680
    The chromosomes of five gaur (Bos gaurus hubbacki) domestic cattle (B indicus cross B taurus) hybrids (three females, two males) were studied using the leucocyte culture method and centromeric (C) banding technique. All the hybrids had a diploid chromosome number of 2n = 58, made up of two submetacentric autosomes (different in size) and 54 acrocentric autosomes, most of which could be arranged in pairs in descending order of size. The sex (X) chromosomes in females were a pair of submetacentric chromosomes smaller than the submetacentric autosomes. The Y chromosome in males was a small submetacentric chromosome. The C banding patterns were useful in identifying the X and Y chromosomes and the inherited submetacentric autosomes from the gaur sire. Phenotypically, the hybrids resembled normal B indicus cross B taurus calves except for the presence of a distinct hump-like dorsal ridge containing the spinous processes of the third to 11th thoracic vertebrae, upright 'deer-like' ears and long lean legs. The potential of these hybrids as important genetic resources for meat production is stressed.
    Matched MeSH terms: X Chromosome
  14. Fulltext Meiotic drive reduces egg-to-adult viability in stalk-eyed flies
    Finnegan SR, White NJ, Koh D, Camus MF, Fowler K, Pomiankowski A
    Proc Biol Sci, 2019 Sep 11;286(1910):20191414.
    PMID: 31480972 DOI: 10.1098/rspb.2019.1414
    A number of species are affected by Sex-Ratio (SR) meiotic drive, a selfish genetic element located on the X-chromosome that causes dysfunction of Y-bearing sperm. SR is transmitted to up to 100% of offspring, causing extreme sex ratio bias. SR in several species is found in a stable polymorphism at a moderate frequency, suggesting there must be strong frequency-dependent selection resisting its spread. We investigate the effect of SR on female and male egg-to-adult viability in the Malaysian stalk-eyed fly, Teleopsis dalmanni. SR meiotic drive in this species is old, and appears to be broadly stable at a moderate (approx. 20%) frequency. We use large-scale controlled crosses to estimate the strength of selection acting against SR in female and male carriers. We find that SR reduces the egg-to-adult viability of both sexes. In females, homozygous females experience greater reduction in viability (sf = 0.242) and the deleterious effects of SR are additive (h = 0.511). The male deficit in viability (sm = 0.214) is not different from that in homozygous females. The evidence does not support the expectation that deleterious side effects of SR are recessive or sex-limited. We discuss how these reductions in egg-to-adult survival, as well as other forms of selection acting on SR, may maintain the SR polymorphism in this species.
    Matched MeSH terms: X Chromosome
  15. The potential immune-eliciting cancer testis antigens in colorectal cancer
    Chi Soh JE, Abu N, Jamal R
    Immunotherapy, 2018 09;10(12):1093-1104.
    PMID: 30185136 DOI: 10.2217/imt-2018-0044
    The identification of cancer testis antigens (CTAs) has been an important finding in the search of potential targets for cancer immunotherapy. CTA is one of the subfamilies of the large tumor-associated antigens groups. It is aberrantly expressed in various types of human tumors but is absent in normal tissues except for the testis and placenta. This CTAs-restricted pattern of expression in human malignancies together with its potential immunogenic properties, has stirred the interest of many researchers to use CTAs as one of the ideal targets in cancer immunotherapy. To date, multiple studies have shown that CTAs-based vaccines can elicit clinical and immunological responses in different tumors, including colorectal cancer (CRC). This review details our current understanding of CTAs and CRC in regard to the expression and immunological responses as well as some of the critical hurdles in CTAs-based immunotherapy.
    Matched MeSH terms: X Chromosome/genetics*
  16. A PCR-based sex determination method for possible application in caprine gender selection by simultaneous amplification of the Sry and Aml-X genes
    Phua AC, Abdullah RB, Mohamed Z
    J. Reprod. Dev., 2003 Aug;49(4):307-11.
    PMID: 14967923
    Sex determination of livestock is performed to achieve the objectives of livestock breeding programmes. Techniques for sex determination have evolved from karyotyping to detecting Y-specific antigens and recently to the polymerase chain reaction (PCR), which appears to be the most sensitive, accurate, rapid and reliable method to date. In this study, a PCR-based sex determination method for potential application in goat breeding programmes was developed. Primers were designed to amplify a portion of the X amelogenin gene (Aml-X) on the X chromosome to give a 300 bp product and Sry gene on the Y chromosome to give a 116 bp product. PCR optimization was performed using DNA template extracted from a whole blood sample of Jermasia goats (German Fawn x Katjang) of both sexes. It was possible to identify the sex chromosomes by amplifying both male- and female-specific genes simultaneously in a duplex reaction with males yielding two bands and females yielding one band. The Aml-X primer set, which served as an internal control primer, did not interfere with amplification of the Y-specific sequence even when a low amount of DNA (1 ng) was used. The duplex reaction subjected to a blind test showed 100% (14/14) concordance, proving its accuracy and reliability. The primer sets used were found to be highly specific and were suitable for gender selection of goats.
    Matched MeSH terms: X Chromosome/genetics
  17. Fulltext Approximate Bayesian analysis of Drosophila melanogaster polymorphism data reveals a recent colonization of Southeast Asia
    Laurent SJ, Werzner A, Excoffier L, Stephan W
    Mol Biol Evol, 2011 Jul;28(7):2041-51.
    PMID: 21300986 DOI: 10.1093/molbev/msr031
    Southeast Asian populations of the fruit fly Drosophila melanogaster differ from ancestral African and derived European populations by several morphological characteristics. It has been argued that this morphological differentiation could be the result of an early colonization of Southeast Asia that predated the migration of D. melanogaster to Europe after the last glacial period (around 10,000 years ago). To investigate the colonization process of Southeast Asia, we collected nucleotide polymorphism data for more than 200 X-linked fragments and 50 autosomal loci from a population of Malaysia. We analyzed this new single nucleotide polymorphism data set jointly with already existing data from an African and a European population by employing an Approximate Bayesian Computation approach. By contrasting different demographic models of these three populations, we do not find any evidence for an early divergence between the African and the Asian populations. Rather, we show that Asian and European populations of D. melanogaster share a non-African most recent common ancestor that existed about 2,500 years ago.
    Matched MeSH terms: X Chromosome
  18. Fulltext The evolutionary history of extinct and living lions
    de Manuel M, Barnett R, Sandoval-Velasco M, Yamaguchi N, Garrett Vieira F, Zepeda Mendoza ML, et al.
    Proc Natl Acad Sci U S A, 2020 May 19;117(20):10927-10934.
    PMID: 32366643 DOI: 10.1073/pnas.1919423117
    Lions are one of the world's most iconic megafauna, yet little is known about their temporal and spatial demographic history and population differentiation. We analyzed a genomic dataset of 20 specimens: two ca. 30,000-y-old cave lions (Panthera leo spelaea), 12 historic lions (Panthera leo leo/Panthera leo melanochaita) that lived between the 15th and 20th centuries outside the current geographic distribution of lions, and 6 present-day lions from Africa and India. We found that cave and modern lions shared an ancestor ca. 500,000 y ago and that the 2 lineages likely did not hybridize following their divergence. Within modern lions, we found 2 main lineages that diverged ca. 70,000 y ago, with clear evidence of subsequent gene flow. Our data also reveal a nearly complete absence of genetic diversity within Indian lions, probably due to well-documented extremely low effective population sizes in the recent past. Our results contribute toward the understanding of the evolutionary history of lions and complement conservation efforts to protect the diversity of this vulnerable species.
    Matched MeSH terms: X Chromosome
  19. Identification of chromosome 21 materials using the whole chromosome 21 specific library
    Isa MN, Boyd E, Turner TL, Tolmie J, Connor JM
    Southeast Asian J. Trop. Med. Public Health, 1995;26 Suppl 1:92-5.
    PMID: 8629150
    The chromosome in situ suppression hybridization or chromosome painting technic was applied to confirm and eliminate the markers involving chromosome 21 segments using a chromosome 21 DNA library. The library ATCCLL21SNO2 was amplified, directly biotinylated using the polymerase chain reaction. The results demonstrated a translocation of chromosome 21 material on chromosome 2 and X and eliminate the origin of the marker. Thus, the technique provides an important tool to complement the conventional G-banding technic.
    Matched MeSH terms: X Chromosome
  20. Fulltext Polymerase chain reaction analysis as a rapid screening test for diagnosis of fragile x syndrome
    Phan, CL, Zubaidah, Z., Gregory, A.R.A., Ten, SK, Kamariah, M.N., Thilagavathi, S., et al.
    Medicine & Health, 2006;1(1):36-44.
    MyJurnal
    Fragile X syndrome is a result of an unstable expansion of (CGG)n trinucleotide sequences in the FMR-1 (Fragile X Mental Retardation 1) gene site at Xq27. In a normal person, n ranges from 6 to 40 repeats with an average of 30 repeats, whereas in a mutated FMR1 gene the sequence is repeated several times over (stuttering gene). Full mutation occurs when n equals 200 repeats or more. Where n equals 50 to 200 repeats, it is a premutation. Fragile X occurs when the FMR-1 gene is unable to make normal amounts of usable Fragile X Mental Retardation Protein, or FMRP. The amount of FMRP in the body is one factor that determines the severity of the Fragile X syndrome. A person with nearly normal levels of FMRP usually has mild or no symptoms, while a person with very little or no normal FMRP has more severe symptoms. The mechanism for the role of the FMRP gene is still being researched upon. However, it has been observed that large numbers of repeats (more than 200) inactivates the gene through a process of methylation and when the gene is inactivated, the cell may make little or none of the needed FMRP. Inheritance is X-linked with reduced penetrance and the frequency of occurrence goes up through generations. The phenotypic manifestations of fragile-X syndrome vary and are largely dependent on the size of the mutation or premutation. The identification of the fragile site on G banded metaphases is a time consuming and delicate process requiring experience and skill, however, molecular diagnosis using DNA analysis and Southern blotting, even though expensive, is more specific in determining the presence or absence of the gene. This study was aimed to establish a rapid polymerase chain reaction (PCR) based - touch down PCR, as a screening method for fragile X syndrome. A total of six cases were analysed. Of these, one was a known case of Fragile X (T1) diagnosed by conventional cytogenetics, two were from the latter’s family members namely, his mother (T2) and father (T3), and the other two (T4 and T5) were randomly selected from patients presenting with dysmorphic features and delayed development respectively. One normal control (TC) was included. Cytogenetic analyses for detection of the fragile site was carried out in all cases. Two culture systems were used, namely the synchronised lymphocyte culture and the folate - thymidine deficient culture. Stained metaphases from the fragile X cultures were screened for the presence of the fragile site on the X chromosome. G-banded karyotyping was done using an image analyser to exclude presence of chromosomal abnormalities. DNA was extracted from these samples and amplified by touch-down PCR. Cytogenetic analysis revealed a folate-sensitive fragile site in the affected male, but none in the other five samples. G-banded karyotyping exhibited no additional chromosomal abnormalities. All extracted DNA samples were successfully amplified. Five of the samples showed presence of the product at the expected band at 552bp, excluding the presence of an expansion of CGG segment of the FMR-1 gene. The absence of a band in an affected individual, suggested a fully mutated allele of FRAXA (Folate Sensitive Fragile Site at Xq28). We succeeded in establishing a slightly modified touch-down PCR analysis. Our study indicates that PCR testing offers a rapid and specific method for screening of normal allele and full mutation of the fragile X gene. We suggest this technique to be applied as a complementary tool for cytogenetic analysis to detect the FRAXA gene.
    Matched MeSH terms: X Chromosome
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