Chromosome Constitution Research Articles

Establishing a reference group for distal 18q-: clinical description and molecular basis

Although constitutional chromosome abnormalities have been recognized since the 1960s, clinical characterization and development of treatment options have been hampered by their obvious genetic complexity and relative rarity. Additionally, deletions of 18q are particularly heterogeneous, with no two people having the same breakpoints. We identified 16 individuals with deletions that, despite unique breakpoints, encompass the same set of genes within a 17.6-Mb region. This group represents the most genotypically similar group yet identified with distal 18q deletions. As the deletion is of average size when compared with other 18q deletions, this group can serve as a reference point for the clinical and molecular description of this condition. We performed a thorough medical record review as well as a series of clinical evaluations on 14 of the 16 individuals. Common functional findings included developmental delays, hypotonia, growth hormone deficiency, and hearing loss. Structural anomalies included foot anomalies, ear canal atresia/stenosis, and hypospadias. The majority of individuals performed within the low normal range of cognitive ability but had more serious deficits in adaptive abilities. Of interest, the hemizygous region contains 38 known genes, 26 of which are sufficiently understood to tentatively determine dosage sensitivity. Published data suggest that 20 are unlikely to cause an abnormal phenotype in the hemizygous state and five are likely to be dosage sensitive: TNX3, NETO1, ZNF407, TSHZ1, and NFATC. A sixth gene, ATP9B, may be conditionally dosage sensitive. Not all distal 18q- phenotypes can be attributed to these six genes; however, this is an important advance in the molecular characterization of 18q deletions.

The transcriptome of follicular cells: biological insights and clinical implications for the treatment of infertility

Oocyte maturation is under strict regulatory control, not only from intrinsic cellular processes, but also extrinsic influences. While the oocyte is directly connected to the surrounding cumulus cells (CCs) via a network of gap junctions facilitating communication and exchange of molecules, it is also influenced by the greater follicular environment. In order to produce an oocyte capable of successfully transmitting the female genetic material and able to support the earliest stages of preimplantation development, cytoplasmic and nuclear maturation must be achieved. Granulosa and CCs play an essential role in the maturation and competence acquisition of the developing oocyte. The fact that these cells are closely associated with the oocyte, share the same microenvironment and can be easily collected during IVF procedures makes them attractive targets for basic research and the development of clinically relevant assays. Analysis of follicular cells is likely to reveal important information concerning the viability and genetic constitution of their associated oocyte, as well as increase our understanding of normal follicular processes and the impact of disorders or of medical interventions such as controlled ovarian stimulation (COS). This review summarizes results obtained during the investigation of granulosa and CCs, and considers the possibilities of using follicular cells as surrogate markers of stimulation response during IVF, oocyte/embryo competence and clinical outcome. In order to summarize the current knowledge obtained from the analysis of follicular cells, a thorough literature search was carried out. Relevant research articles published in English up to March 2013 were reviewed. Multiple groups of genes expressed in follicular cells have been identified as possible indicators of ovulation, oocyte maturity, fertilization, chromosome status, ability to generate embryos capable of reaching the blastocyst stage of development, embryo morphology and the establishment of a pregnancy. However, there is a general lack of uniformity concerning groups of gene biomarkers among different studies. Extensive investigation of genes and proteins of granulosa and CCs has provided a detailed insight into the follicular microenvironment surrounding oocytes. It was evident from the data reviewed that the gene expression of follicular cells influences and is influenced by the oocyte, affecting factors such as maturity, chromosomal constitution, viability and competence. However, a general lack of overlap among genes identified as potentially useful biomarkers suggests that the transcriptome of follicular cells could be affected by multiple intrinsic factors, having to do with the patient and possibly the aetiology of infertility, as well as extrinsic factors, such as hormonal stimulation. Further work is required in order to establish a universally applicable, non-invasive test for the determination of oocyte competence based upon follicular cell assessment.

Constitutional 11q14-q22 chromosome deletion syndrome in a child with neuroblastoma MYCN single copy

Constitutional 11q deletion is a chromosome imbalance possibly found in MCA/MR patients analyzed for chromosomal anomalies. Its role in determining the phenotype depends on extension and position of deleted region. Loss of heterozygosity of 11q (region 11q23) is also associated with neuroblastoma, the most frequent extra cranial cancer in children. It represents one of the most frequent cytogenetic abnormalities observed in the tumor of patients with high-risk disease even if germline deletion of 11q in neuroblastoma is rare. Hereby, we describe a 18 months old girl presenting with trigonocephaly and dysmorphic facial features, including hypotelorism, broad depressed nasal bridge, micrognathia, synophrys, epicanthal folds, and with a stage 4 neuroblastoma without MYCN amplification, carrying a germline 11q deletion (11q14.1-q22.3), outside from Jacobsen syndrome and from neuroblastoma 11q critical regions. The role of 11q deletion in determining the clinical phenotype and its association with neuroblastoma development in the patient are discussed.

Time lapse observation during embryo development differentiates blastocyst quality but not chromosome constitution or gender

Continual assessment of embryos during in vitro culture using time lapse observation allows for a more in depth understanding of this dynamic process. The objective of this study was to examine embryo morphology using time lapse observation for characterization of top quality blastocysts, embryo gender and blastocyst chromosome complement.

Increased efficiency on trophectoderm analysis during preimplantation genetic diagnosis (PGD)

Aneuploidies are the major cause of implantation failure or pregnancy loss. Arraybased Comparative Genomic Hybridization (arrayCGH) offers detailed information about the chromosomal constitution of the embryos from patients with a high risk of aneuploid conceptuses due to translocations.

No embryo gender bias is observed following blastocyst comprehensive chromosome screening

Human gender differences exist for chromosomal constitution, metabolism and physiology. It has also been reported that male embryos develop in vitro faster during the preimplantation stages than female embryos. The aim of this study was to evaluate the impact of gender on blastocyst chromosomal complement and development, and to determine if a gender ratio bias increases the likelihood of a male euploid blastocyst transfer.

Chromosomal analysis by array comparative genomic hybridization reveals high normality of blastocysts taht develop from embryos containing multinucleated blastomeres

Embryos containing multinucleated blastomeres, so called multinucleated embryos are often present even in the good quality embryos, when we perform the morphological evaluation of the embryos under an inverted microscope. Multinucleated embryos have been believed to have highly chromosomal abnormality and result in lower pregnancy rate. On the other hand, multinucleated embryos often develop up to blastocyst stage. And there is a report of giving birth to normal babies by transfer of multinucleated embryo. In this study, the viability of multinucleated embryos was estimated by blastocyst formation, and their chromosome constitutions analyzed by Array Comparative Genomic Hybridization (aCGH). Clinical study. Sixty multinucleated embryos intended for disposal without transfer were used after obtaining the informed consent of the patients between May and December 2012. These multinucleated embryos were cultured to the blastocyst stage. Their blastocyst formation rate and the good blastocyst rates in multinucleated embryos were compared to that in embryos without multinucleated blastomeres (non-multinucleated embryos). In addition, 11 blastocysts developing from multinucleated embryos were chromosomally analyzed by aCGH. The blastocyst formation rate in Day5 and Day6 were 13.3% (8/60), 30.0% (18/60) of multinucleated embryos and 34.9% (22/63), 46.0% (29/63) of non-multinucleate embryos, respectively. The significal difference was found in Day5 blastocyst develpoment. The good blastocyst rate of them was 23.3% (14/60) of multinucleated embryos and 15.9% (10/63) of non-multinucleated embryos. In addition, 10 of 11 good blastocysts from multinucleated embryos showed euploid. In this study, multinucleated embryos have the same viability as non-multinucleated embryos morphologically and chromosomally. These results suggest that multinucleated embryos to grow up to blastocysts are possible to use for embryo transfer.

Dissociable Effects of Sry and Sex Chromosome Complement on Activity, Feeding and Anxiety-Related Behaviours in Mice

Whilst gonadal hormones can substantially influence sexual differentiation of the brain, recent findings have suggested that sex-linked genes may also directly influence neurodevelopment. Here we used the well-established murine ‘four core genotype’ (FCG) model on a gonadally-intact, outbred genetic background to characterise the contribution of Sry-dependent effects (i.e. those arising from the expression of the Y-linked Sry gene in the brain, or from hormonal sequelae of gonadal Sry expression) and direct effects of sex-linked genes other than Sry (‘sex chromosome complement’ effects) to sexually dimorphic mouse behavioural phenotypes. Over a 24 hour period, XX and XY gonadally female mice (lacking Sry) exhibited greater horizontal locomotor activity and reduced food consumption per unit bodyweight than XX and XY gonadally male mice (possessing Sry); in two behavioural tests (the elevated plus and zero mazes) XX and XY gonadally female mice showed evidence for increased anxiety-related behaviours relative to XX and XY gonadally male mice. Exploratory correlational analyses indicated that these Sry-dependent effects could not be simply explained by brain expression of the gene, nor by circulating testosterone levels. We also noted a sex chromosome complement effect on food (but not water) consumption whereby XY mice consumed more over a 24hr period than XX mice, and a sex chromosome complement effect in a third test of anxiety-related behaviour, the light-dark box. The present data suggest that: i) the male-specific factor Sry may influence activity and feeding behaviours in mice, and ii) dissociable feeding and anxiety-related murine phenotypes may be differentially modulated by Sry and by other sex-linked genes. Our results may have relevance for understanding the molecular underpinnings of sexually dimorphic behavioural phenotypes in healthy men and women, and in individuals with abnormal sex chromosome constitutions.

Methylation‐specific multiplex ligation‐dependent probe amplification: utility for prenatal diagnosis of parental origin in human triploidy

When a triploid pregnancy is diagnosed prenatally, gynaecologists have traditionally relied on the histopathological examination of the tissue from the terminated pregnancy to determine if the pregnancy is molar. However, reproducibility is poor and variability is high when diagnosing hydatidiform moles. Triploid pregnancies can have either the chromosomal constitution of two maternal and one paternal set, or two paternal and one maternal set, but only the conceptuses with two paternal sets have the potential to cause maternal complications. Therefore, it would be beneficial to introduce a method that gives the gynaecologist the parental origin of the genome of the triploid conceptus as early as possible, without delaying the process by first collecting parental samples. Using methylation-specific multiplex ligation-dependent probe amplification, we measured methylation levels at different imprinted sites. We were able to correctly determine the parental origin of the genome in all 105 triploid pregnancies analysed. We present methylation-specific multiplex ligation-dependent probe amplification as a method capable of determining the parental origin of the genome of triploid conceptuses within 24 h; it is inexpensive, simple and easy to use, and parental samples are not needed.

Trisomy 18p caused by a supernumerary marker with a chromosome 13/21 centromere: A possible recurrent chromosome aberration

We present a clinical and molecular cytogenetic characterization of two new patients with a complex supernumerary marker consisting of the entire short arm of chromosome 18 with a chromosome 13/21 centromere. One patient is a girl with a nonsyndromic intellectual disability and the second is a prenatally diagnosed fetus. To our knowledge, these are the fourth and fifth such cases to be described in the literature, suggesting the existence of a possible recurring constitutional structural chromosome abnormality.

Hereditary Syndromes With Associated Renal Neoplasia

Many hereditary tumor syndromes are associated with neoplasms of the kidney. It is becoming increasingly well recognized that a given familial tumor syndrome may be very heterogenous in clinical appearance and that unrecognized patients may present initially for the treatment of a renal mass. It is therefore important for surgical pathologists to be aware of the specific gross and microscopic findings in the kidney that suggest a possible syndromic association. In this review, we detail the histologic features of syndromic-associated renal neoplasms, describe the presence of characteristic changes in the background renal parenchyma, and provide an update on associated extrarenal manifestations for each of the following syndromes: von Hippel-Lindau disease, hereditary papillary renal cell carcinoma (RCC), hereditary leiomyomatosis-RCC, Birt-Hogg-Dubé syndrome, tuberous sclerosis complex, germline succinate dehydrogenase mutation, hereditary nonpolyposis colorectal cancer syndrome, hyperparathyroidism-jaw tumor syndrome, PTEN hamartoma syndrome, constitutional chromosome 3 translocation, and familial nonsyndromic clear cell RCC. We also include a synopsis of renal medullary carcinoma because of its association with hereditary hemoglobinopathies.

Cytogenetic and single nucleotide polymorphism array findings in soft tissue tumors in infants

Soft tissue tumors in children under one year of age (infants) are rare. The etiology is usually unknown, with external factors or congenital birth defects and hereditary syndromes being recognized in only a small proportion of the cases. We ascertained the cytogenetic findings in 16 infants from whom tumor tissue had been obtained during a 25-year period. In eight of them, single nucleotide polymorphism (SNP) array analyses could also be performed. No constitutional chromosome aberrations were detected, and assessment of clinical files did not reveal any congenital or later anatomical defects. Three tumors--one infantile fibrosarcoma, one embryonal rhabdomyosarcoma, and one angiomatoid fibrous histiocytoma (AFH)--had abnormal karyotypes. As the AFH had an exchange between chromosome arms 12p and 15q, additional fluorescence in situ hybridization and reverse transcription-polymerase chain reaction analyses were performed, unexpectedly revealing an ETV6/NTRK3 fusion. Three of the eight tumors, including the AFH with an abnormal karyotype, analyzed by SNP array showed aberrations (loss of heterozygosity or imbalances). The present series suggests that the addition of array-based technologies is valuable for detecting underlying pathogenetic mechanisms.

Cytogenetic and Y-chromosome Micro-deletions Analysis of Infertile Indian Males with non-obstructive Azoospermia and Severe Oligozoospermia

This study aimed to determine the frequency and type of chromosome anomalies and Y-chromosome microdeletions in Indian infertile males by using non-obstructive azoospermia and severe oligozoospermia. The study included 168 Indian infertile males. G-banding cytogenetic analysis was performed on the peripheral blood lymphocytes of 91 men with non-obstructive azoospermia and 77 men with oligozoospermia. A molecular genetic analysis of Y-chromosome was also performed with multiplex polymerase chain reaction (M-PCR) amplification by using15 Y-specific sequence-tagged sites (STSs) of azoospermia factor (AZF) region to screen the microdeletions in AZFs region of Ychromosome. Out of 168 cases, 152 had normal karyotype 46,XY chromosomal constitution. Cytogenetic abnormalities were found in 13 (7.74%) infertile patients. The frequency of chromosomal anomalies for non-obstructive azoospermia 7 (4.16%) was slightly higher than severe oligozoospermia 6 (3.57%). Chromosomal variants werefound in 2.38% patients. The microdeletions of Y-chromosome were observed in 1.19% and 0.59% patients with non-obstructive azoospermia and severe oligozoospermia, respectively. Microdeletions of both AZFa and AZFc genes identified with normal karyotype. This study has provided information that genetic anomalies act as a risk factor for infertility. It is therefore suggested that genetic techniques should be used for diagnosis purpose to obtain the genetic data for possible genetic counseling/cure to minimize the risk of transmitted genetic anomalies.

Production of hexaploid triticale by a synthetic hexaploid wheat-rye hybrid method

Hexaploid triticale, including its primary and secondary forms, is an important forage crop and a promising energy plant. Primary forms are usually developed by crossing Triticum turgidum L. with rye, with secondary forms obtained by crossing primary hexaploid triticale and/or hexaploid wheat with octoploid triticale. In this study, we developed an effective method for production of hexaploid triticale via hybridization of synthetic hexaploid wheat (SHW) with rye. The three employed SHW lines were derived from hybridization of T. turgidum with Aegilops tauschii Cosson, and inherited meiotic restitution genes, which can promote the formation of functional gametes in haploid status, from their T. turgidum parents. Although the resulting tetraploid F-1 hybrids with rye (genome ABDR) produced amphiploids (octoploid triticale) and partial amphiploids, the final hybrid products obtained through fertility selection over several generations were hexaploids. These hexaploids were the result of preferential elimination of D-genome chromosomes. In addition to complete hexaploid triticale with 28 intact A/B and 14 intact R chromosomes, we obtained hexaploid triticales with other chromosome constitutions, including monosomic, substitution, and translocation lines. Chromosomes 2D and 5D from the wild species A. tauschii were incorporated into the hexaploid triticales. Out of eight analyzed stable lines derived from three different SHW-L1/rye F-1 plants, we observed four lines with small-fragment translocations between wheat and rye chromosomes. Rapid production of hexaploid triticales using this method involves two factors: (1) hybridization between hexaploid wheat with a meiotic restitution gene(s) and rye and (2) selection for good fertility during F-3 and subsequent generations.

Chromosomal mapping of microsatellite repeats in the rock bream fish Oplegnathus fasciatus, with emphasis of their distribution in the neo-Y chromosome.

Despite the theoretical and experimental progress, our understanding on sex chromosome differentiation is still diagrammatic. The accumulation of repetitive DNA sequences is believed to occur in early stages of such differentiation. As fish species present a wide range of sex chromosome systems they are excellent models to examine the differentiation of these chromosomes. In the present study, the chromosomal distribution of 9 mono-, di- and tri-nucleotide microsatellites were analyzed using fluorescence in situ hybrization (FISH) in rock bream fish (Oplegnathus fasciatus), which is characterized by an X1X2Y sex chromosome system. Generally, the males and females exhibited the same autosomal pattern of distribution for a specific microsatellite probe. The male specific Y chromosome displays a specific amount of distinct microsatellites repeats along both arms. However, the accumulation of these repetitive sequences was not accompanied by a huge heterochromatinization process. The present data provide new insights into the chromosomal constitution of the multiple sex chromosomes and allow further investigations on the true role of the microsatellite repeats in the differentiation process of this sex system.

Karyological characterization of the Japanese water shrew,Chimarrogale platycephala(Soricidae, Soricomorpha)

We analyzed the karyological criteria of the Japanese water shrew, Chimarrogale platycephala in central Honshu. Only a few studies on the karyotype of this species for samples from Aomori Prefecture, northernmost Honshu, the Japanese Islands have been published. Our current results indicate that the chromosomal constitutions are fundamentally identical to those of previous studies. In addition, heteromorphism in the largest autosomal pair (no. 1 homologue) was also observed, in agreement with previous data. This heteromorphism of the no. 1 homologue is considered a usual phenomenon in C. platycephala based on previous and current results. In addition, another autosomal heteromorphism on medium-sized subtelocentrics was observed as the first example. The heteromorphic regions were positively stained by C-banding. Moreover, a cline seemed to appear in the degree of the heteromorphic status along south to north in comparison with previous studies. In C. platycephala, there are several kinds of heterochromati...

Trissomia 18: revisão dos aspectos clínicos, etiológicos, prognósticos e éticos

OBJETIVO: Revisar as características clínicas, etiológicas, diagnósticas e prognósticas da trissomia do cromossomo 18 (síndrome de Edwards). FONTES DE DADOS: Foram pesquisados artigos científicos presentes nos portais MedLine, Lilacs e SciELO, utilizando-se os descritores 'trisomy 18' e 'Edwards syndrome'. A pesquisa não se limitou a um período determinado e englobou artigos presentes nestes bancos de dados. SÍNTESE DOS DADOS: A síndrome de Edwards é uma doença caracterizada por um quadro clínico amplo e prognóstico bastante reservado. Há descrição na literatura de mais de 130 anomalias diferentes, as quais podem envolver praticamente todos os órgãos e sistemas. Seus achados são resultantes da presença de três cópias do cromossomo 18. A principal constituição cromossômica observada entre estes pacientes é a trissomia livre do cromossomo 18, que se associa ao fenômeno de não disjunção, especialmente na gametogênese materna. A maioria dos fetos com síndrome de Edwards acaba indo a óbito durante a vida embrionária e fetal. A mediana de sobrevida entre nascidos vivos tem usualmente variado entre 2,5 e 14,5 dias. CONCLUSÕES: O conhecimento do quadro clínico e do prognóstico dos pacientes com a síndrome de Edwards tem grande importância no que diz respeito aos cuidados neonatais e à decisão de instituir ou não tratamentos invasivos. A rapidez na confirmação do diagnóstico é importante para a tomada de decisões referentes às condutas médicas. Muitas vezes, as intervenções são realizadas em condições de emergência, sem muita oportunidade de reflexão ou discussão, e envolvem questões médicas e éticas difíceis.

Disorder of sexual development in a Yorkshire terrier (78, XY; SRY-positive)

A 9-month-old Yorkshire terrier was admitted to the clinic because of abnormal sexual behaviour and clitoral hypertrophy. External examination confirmed standard development of caudal genital organs: vagina, vulva and cervix uteri. Serum profile of gonadotropin hormones 17 β-estradiol (<10.0 pg.ml(-1)) and testosterone (9.1 ng.ml(-1)) revealed the presence of testicular tissue. A midline laparotomy was performed to detect the cranial parts of the genital system. Gonads resembling testicles, structures indicating epididymis and rudimentary deferent ducts were resected, along with adherent part of the uterus. Cytogenetic analysis showed a male chromosomal complement 78, XY in all metaphases of the studied Yorkshire terrier dog. The chromosomal constitution was confirmed by fluorescence in situ hybridisation (FISH) with whole-chromosome painting probes specific for chromosomes X and Y, as well as by polymerase chain reaction (PCR) amplification of the 271-bp Y-linked fragment of SRY (the sex-determining region on the Y chromosome) gene. Sequencing of the dog's SRY gene coding region did not reveal any mutation. To search for potential mutation in the SOX9 gene (Sry-box containing gene 9), which is considered to be one of the key genes involved in the sex determination process, the PCR fragments of exons 1, 2 and 3 originating from the canine patient were sequenced in order to compare with both male and female healthy control dogs. In the analysed regions of the SOX9 gene, no mutation was found.

Cytogenetic Evolution in a Patient with Chronic developing a Secondary Acute Myelogenous Leukemia Subtype M5 Resistant to Imatinib Mesylate Therapy

Here we report an unusual case of Chronic Myelogeneous Leukemia (CML) developing towards an Acute Myelogeneous Leukemia subtype M5 (AML-M5). The chromosomal constitution was at (final) stage of AML-M5: Philadelphia chromosome positivity with multiple trisomies, a double t (9; 22) (q34; q11) and an AML1/MDS1/EVI1 (AME) fusion transcript resulting from a t (3; 21) (q26; q22). The latter translocation was detectable first in blast phase of CML and remained present in AML-M5 stage. Overall, four chromosomal analyses were done within 19 months, describing the ongoing karyotypic evolution during this transformation. Unfortunately this exceptional patient did not respond to Imatinib- (IM) or Nilotinib-therapy. These finding May by a first hint that CML-patients acquiring a t (3; 21) (q26; q22) might be appropriate to bone marrow transplantation rather than for IM-therapy.

Effect of chromosome constitution variations on the expression of Turner phenotype

Turner syndrome (TS) is a chronic disease related to haploinsufficiency of genes that are normally expressed in both X chromosomes in patients with female phenotype that is associated with a wide range of somatic malformations. We made detailed cytogenetic and clinical analysis of 65 patients with TS from the region of Recife, Brazil, to determine the effects of different chromosome constitutions on expression of the TS phenotype. Overall, patients with X-monosomy exhibited a tendency to have more severe phenotypes with higher morbidity, showing its importance in TS prognosis. Additionally, we found rare genetic and phenotypic abnormalities associated with this syndrome. To the best of our knowledge, this is the first case of 45,X,t(11;12)(q22;q22) described as a TS karyotype. Turner patients usually have normal intelligence; however, moderate to severe levels of mental retardation were found in 5 TS cases, which is considerate a very uncommon feature in this syndrome.