Trisomy 8 mosaicism syndrome. Two cases demonstrating variability in phenotype

An unusual case of trisomy 8 mosaicism complicated by coexistence of phenylketonuria

Trisomy 8 syndrome, also known as " Warkany syndrome type 2 ", was first reported in 1971. Complete trisomy 8 are mostly aborted spontaneouslyinthe first trimester. Trisomy 8 mosaicism (T8M), predominated in the current cases reported. Itisahighlyheterogeneous Chromosome disorder. We know little about its effects on fertility. In this case, a patient with T8M combined with phenylketonuria was diagnosed. She's mentally retarded. After evaluating the anatomy and function of the reproductive system, the patient conceived through preimplantationgenetictesting-intracytoplasmicsperminjection-embryotransfer (PGT-ICSI-ET) and obtained a healthy fetus, which is the first report. The study focuses on the maintenance of fertility in patients with T8M, the effects of phenylketonuria and genetic counseling.

Prenatal diagnosis of trisomy 8 mosaicism, initially identified by cffDNA screening

BACKGROUND

So called cell-free fetal DNA (cffDNA) in the maternal plasma, which is derived from placenta, is widely used to screen fetal aneuploidies, including trisomy 21, 18, 13 and sex chromosomes. Here we reported a case of trisomy 8 mosaicism (T8M), which was initially identified via cffDNA screening in noninvasive prenatal testing (NIPT).

METHODS

A 35-year-old woman received cffDNA screening at 17th week of gestation. Amniocentesis was performed subsequently, and karyotyping, single-nucleotide polymorphism array (SNP-array) and BACs-on-Beads™ (BoBs™) were used to determine fetal chromosome content. Interphase fluorescence in situ hybridization (FISH) was applied to determine the copy number of chromosome 8.

RESULTS

An enhanced risk for fetal trisomy 8 was identified by cffDNA screening in the studied pregnant woman. After amniocentesis trisomy 8 was found in 1 of 73 metaphases. SNP-array on DNA derived from cultured amniocytes and neonatal cord blood cells suggested the presence of T8M. Interphase FISH on native neonatal cord blood cells confirmed T8M with a percentage of 10%. The Bobs™ fluorescence data also suggested that 8q23-8q24 was amplified.

CONCLUSIONS

The current study shows that NIPT is suited to provide hints on rare autosomal trisomies, which have to be further validated and confirmed by other approaches.

Early and Innovative Rehabilitation in Warkany Syndrome 2 Associated with Agenesis of the Corpus Callosum: A Case Report

Trisomy 8 mosaicism syndrome (T8MS) or “Warkany’s syndrome 2” is a rare chromosomal disorder characterized by three copies of chromosome 8 in some cells of the body. T8MS incidence in the world population is about 1/25,000–50,000 live births with a 5:1 ratio between males and females. Since chromosomal mosaicism is often present in this syndrome, affected subjects present a phenotype varying from mild dysmorphism to severe structural anomalies. Malformations, including corpus callosum agenesis and renal abnormalities, have been described by many studies. We present a case in a girl 36 months in age, born to assisted fertilization (FIVET) and prenatal diagnosis by amniocentesis. In a fetus in the 22 week of gestation, she presented trisomy 8 mosaicism with ventriculomegaly, agenesis of the corpus callosum and a sequence of polymalformations. Through the early identification of symptoms that gradually occurred during development, the girl was submitted, early, to innovative complex instrumental using virtual reality (VR) rehabilitation. This study involves continuous monitoring and early management of symptoms, with the aim of improving the neurobehavioral outcomes of children with this rare disease by inducing structural neuroplastic responses and significantly reducing the impact that this disorder has on the development of children born without corpus callosum.

Bilateral severe microphthalmia in a neonate with trisomy 8 mosaicism: A new finding

Mosaic Trisomy 8 is a rare chromosomal abnormality estimated to occur one in 30,000 newborns. The phenotype is highly variable and the severity does not appear to be correlated with the proportion of cells that contain the additional chromosome. Ocular involvement in Trisomy 8 mosaicism has previously been described to include corneal opacities, retinal dystrophy, coloboma, and unilateral microphthalmia. We report a case of severe bilateral microphthalmia in a neonate with Trisomy 8 mosaicism, a previously unrecognized ophthalmic manifestation.

Contribution of de novo and inherited rare CNVs to very preterm birth

BACKGROUND

The genomic contribution to adverse health sequelae in babies born very preterm (<32 weeks' gestation) is unknown. We conducted an investigation of rare CNVs in infants born very preterm as part of a study to determine the feasibility and acceptability of a larger, well-powered genome-wide investigation in the UK, with follow-up using linked National Health Service records and DNA storage for additional research.

METHODS

We studied 488 parent-offspring trios. We performed genotyping using Illumina Infinium OmniExpress Arrays. CNV calling and quality control (QC) were undertaken using published protocols. We examined de novo CNVs in infants and the rate of known pathogenic variants in infants, mothers and fathers and compared these with published comparator data. We defined rare pathogenic CNVs as those consistently reported to be associated with clinical phenotypes.

RESULTS

We identified 14 de novo CNVs, representing a mutation rate of 2.9%, compared with 2.1% reported in control populations. The median size of these CNV was much higher than in comparator data (717 kb vs 255 kb). The rate of pathogenic CNVs was 4.3% in infants, 2.7% in mothers and 2% in fathers, compared with 2.3% in UK Biobank participants.

CONCLUSION

Our findings suggest that the rate of de novo CNVs, especially rare pathogenic CNVs, could be elevated in those born very preterm. However, we will need to conduct a much larger study to corroborate this conclusion.

Karyotyping and prenatal diagnosis of 47,XX,+ 8[67]/46,XX [13] Mosaicism: case report and literature review

BACKGROUND

Trisomy 8 mosaicism has a wide phenotypic variability, ranging from mild dysmorphic features to severe malformations. This report concluded a female pregnant woman with trisomy 8 mosaicism, and carefully cytogenetic diagnoses were performed to give her prenatal diagnostic information. This report also provides more knowledge about trisomy 8 mosaicism and the prenatal diagnostic for clinicians.

CASE PRESENTATION

In this present study, we reported one case of pregnancy woman with trisomy 8 mosaicism. Noninvasive prenatal testing prompted an abnormal Z-score, but further three dimension color ultrasound result suggested a single live fetus with no abnormality. The phenotypic of the pregnant woman was normal. Based on our results, there were no abnormal initial myeloid cells (< 10^- 4), which suggested that the patient had no blood diseases. The peripheral blood karyotype of the patient was 47,XX,+ 8[67]/46,XX [13], and karyotype of amniotic fluid was 46, XX. The next generation sequencing (NGS) result suggested that the proportions of trisomy 8 in different tissues were obviously different; and 0% in amniotic fluid. Last, the chromosomes of the patient and her baby were confirmed using chromosome microarray analysis (CMA), and the results were arr[GRCh37](8) × 3,11p15.5p13(230750-33,455,733) × 2 hmz and normal.

CONCLUSIONS

This pregnancy woman was trisomy 8 mosaicism, but the phenotypic was normal, and also the fetus was normal. Carefully cytogenetic diagnoses should be performed for prenatal diagnose.

Prenatal detection of trisomy 8 mosaicism: Pregnancy outcome and follow up of a series of 17 consecutive cases

OBJECTIVE

To study the outcome of a series of individuals with prenatal detection of trisomy 8 mosaicism by chorionic villus sampling (CVS) and/or amniocentesis.

STUDY DESIGN

The databases of two Italian genetics units were reviewed to identify all consultations requested during pregnancy because of trisomy 8 mosaicism. To evaluate the pregnancy outcome, the regional registry of congenital malformations (including terminations of pregnancies) was consulted; additional follow-up data were collected by a telephone interview. The following outcomes were analysed: delivery, pre- and post-natal growth, psychomotor development, major malformations, other diseases/complications.

RESULTS

A total of 17 consecutive cases of trisomy 8 mosaicism were identified. Fourteen cases were first detected among women undergoing prenatal diagnosis by CVS; the remaining ones were identified among women who underwent amniocentesis. In most cases diagnosed by CVS, the chromosomal anomaly was only detected in long-term cell cultures (10/14) and was not confirmed by amniocentesis (11/13). There were two terminations of pregnancy and 15 live births; no major birth defects were observed among live born infants and only a case with prenatal and postnatal growth retardation was observed (mean age at follow-up interview was 5.9 years).

CONCLUSION

Our data showed an overall positive prognosis for cases with an apparent confined placental mosaicism and those with low-level mosaicism in amniotic fluid if no congenital anomalies were detected by foetal ultrasound examinations. However, larger studies are warranted to better define the associated risk of neurodevelopmental anomalies.

Unrevealed mosaicism in the next-generation sequencing era

Mosaicism refers to the presence in an individual of normal and abnormal cells that are genotypically distinct and are derived from a single zygote. The incidence of mosaicism events in the human body is underestimated as the genotypes in the mosaic ratio, especially in the low-grade mosaicism, stay unrevealed. This review summarizes various research outcomes and diagnostic questions in relation to different types of mosaicism. The impact of both tested biological material and applied method on the mosaicism detection rate is especially highlighted. As next-generation sequencing technologies constitute a promising methodological solution in mosaicism detection in the coming years, revisions in current diagnostic protocols are necessary to increase the detection rate of the unrevealed mosaicism events. Since mosaicism identification is a complex process, numerous examples of multistep mosaicism investigations are presented and discussed.

Immunodeficiency in patients with 49,XXXXY chromosomal variation

Boys affected with 49,XXXXY sex chromosomal variation have been described to have high incidence of recurrent otitis media and asthma, the cause of which is unknown. We hypothesized that primary immunodeficiency occurs in patients with XXXXY aneuploidy. To investigate this, 31 boys with known 49,XXXXY were evaluated through a multidisciplinary clinic. Screening history was performed using the "10 Warning Signs of primary immunodeficiency" (Jeffrey Modell Foundation), as well as by history of atopic and autoimmune conditions. Of the 31 boys, 20 had at least two warning signs of primary immunodeficiency, and five had four or more signs. Sixteen had history of recurrent pneumonia, and 15 carried the diagnosis of asthma. Of the 10 who underwent immunologic screening, eight showed some evidence of impaired antibody responses to polysaccharide antigens, and one was diagnosed with specific antibody deficiency. These preliminary results suggest a high incidence of both atopy and antibody deficiency in boys with 49,XXXXY.

Heterotopic ossification after patellar tendon repair in a man with trisomy 8 mosaicism: a case report and literature review

INTRODUCTION

Heterotopic ossification is the abnormal formation of lamellar bone in soft tissue. Its presence jeopardizes functional outcome, impairs rehabilitation and increases costs due to subsequent surgical interventions.

CASE PRESENTATION

We present a case of a 32-year-old African-American man with trisomy 8 mosaicism who developed severe heterotopic ossification of his right extensor mechanism subsequent to repair of a patellar tendon rupture.

CONCLUSION

To the best of our knowledge there are no prior reports of heterotopic ossification as a complication of patellar tendon repair. This case may suggest an association between trisomy 8 mosaicism and increased risk of heterotopic ossification.

Trisomy 8 mosaicism and favorable outcome after treatment of infantile spasms: case report

Constitutional mosaic trisomy 8 syndrome occurs in approximately 1 of 35 000 live births. Clinically, it has a variable presentation. Some patients are asymptomatic, while others have multisystemic involvement. The overall incidence of neurological abnormalities has not been reported, but seizures are among the neurological symptoms associated with this condition. Previous reports describe astatic seizures, complex partial seizures, generalized tonic-clonic seizures, and absence seizures with the age of onset varying from 3 months to early childhood. However, instances of infantile spasms and the patients' response to treatment have not been reported to our knowledge. Accordingly, we report a case of a patient with constitutional mosaic trisomy 8 syndrome and infantile spasms, who became seizure free after treatment with adrencorticotropic hormone and clonazepam.

Intrauterine growth retardation associated with precocious puberty and sertoli cell hyperplasia

The original description of patients with Russell-Silver syndrome included precocious puberty, the mechanism of which was unclear. We describe a child with a Russell-Silver syndrome-like phenotype who presented with precocious puberty that was associated with hyperplasia of the Sertoli cells. The patient was found to have an immature cryptorchid testicle; hyperplastic Sertoli cells were also aneuploid carrying trisomy 8. This chromosomal abnormality was present in Sertoli cells only and could not be detected in peripheral lymphocytes, tunica vaginalis, or other, normal, testicular tissue. Sertoli cells in culture showed excess aromatization providing an explanation for the rapid advancement of the patient's bone age. We conclude that in a patient with a Russell-Silver syndrome-like phenotype, Sertoli cell hyperplasia was associated with somatic trisomy 8, increased aromatization, and gonadotropin-independent precocious puberty.

Characterization of trisomic natural killer cell abnormalities in a patient with constitutional trisomy 8 mosaicism

Malignancies found in children and adults with constitutional trisomy 8 mosaicism (CT8M) could be in part the consequence of dysfunction of trisomic immune cells. An adult patient exhibiting trisomy in the entire natural killer (NK) cell population has made possible the characterization of trisomy 8-positive NK cells. The study showed normal cytotoxic activity but predominance of an immunosenescent phenotype (CD56(dim)CD94/NKG2(bright)) characterized by a weak response to IL-2, increased upregulation of CD95/Fas, and impaired TNF-alpha production. As these defects may contribute to the escape and expansion of neoplastic cells, the authors hypothesize that cancer predisposition in CT8M may be partly a result of altered immunosurveillance.

Trisomy 8q and partial trisomy 22 in a 43-year-old man with moderate intellectual disability, epilepsy and large cell non-Hodgkin lymphoma

Partial trisomies are chromosome abnormalities resulting in a broad range of malformations depending on the size and location of the chromosomal rearrangement. Whereas diagnosis of these syndromes is usually made in early childhood, few descriptions exist about the clinical picture in adulthood. We report on a patient diagnosed at the age of 43 years with a 47,XY,+der(22)t(8;22)(q24.13;q11.21) karyotype and predominant clinical features of trisomy 8q. To our knowledge, this is the oldest patient described with a partial trisomy 8. The patient presented with moderate intellectual disability, a past history of epilepsy and facial anomalies. In addition, a large cell non-Hodgkin lymphoma was diagnosed in adulthood. Detailed breakpoint mapping by single nucleotide polymorphism (SNP) arrays showed that the derivative chromosome contains a full-length copy of the C-MYC oncogene. Given that trisomy 8q is the most frequent secondary chromosomal abnormality in hematological diseases, the possibility of a genetic predisposition for these disorders in patients with 8q duplication is raised.

Trisomy 8 mosaicism in a patient with heterotaxia

Constitutional trisomy 8 mosaicism (CT8M) is a relatively rare trisomy in humans with a characteristic phenotype. We report an infant with the characteristic CT8M phenotype in addition to heterotaxia. A number of chromosomal abnormalities have been reported in association with laterality defects but this is the first time heterotaxia is reported in CT8M. In addition to expanding CT8M phenotype, our report may provide insight into the mechanism of heterotaxia.

Trisomy 8 mosaicism: selective growth advantage of normal cells vs. growth disadvantage of trisomy 8 cells

A fetus with trisomy 8 mosaicism was identified prenatally due to an abnormal maternal serum triple screen. Tissue samples were taken at birth to determine the level of trisomy 8 mosaicism found within embryonic and extra-embryonic tissues, rates of cell division for the two cell lines, and the effect of mosaicism on the phenotype. The level of trisomy 8 cells in blood and fibroblasts was higher than in placental tissue. Cell cycle kinetics, by incorporation of bromodeoxyuridine for 48 hr, was not significantly different between the trisomy 8 and normal cells for blood or amnion. Fluorescent in situ hybridization (FISH) using centromeric probe for chromosome 8 showed significantly more trisomy 8 in interphase vs. metaphase in lymphoblasts, umbilical cord fibroblasts, and chorion. The loss of trisomy 8 cells is not due to anaphase lag, as determined by micronuclei analysis. The similarity of cell cycle kinetics between trisomy 8 cells and normal diploid cells suggests some trisomy 8 cells are exiting the cell cycle prematurely. This growth disadvantage of trisomy 8 cells results in the appearance of growth advantage for diploid cells.

Familial transmission of a small supernumerary marker chromosome 8 identified by FISH: an update

A father and his 2 daughters were previously determined to carry a small, supernumerary marker chromosome [Chudley et al., 1983]. The origin of this marker could not be determined by standard cytogenetic techniques. In this study, fluorescence in situ hybridization (FISH) studies identified the marker chromosome as a pericentric derivative of chromosome 8. The father has low grade mosaicism for this marker and is phenotypically normal. Both daughters are non-mosaic and show developmental delays and somewhat differing clinical findings. The phenotypes of the 2 sisters are compared with those previously reported for supernumerary der(8) patients. This is the first report of familial transmission of a supernumerary der(8) marker chromosome.

Trisomy 8 preceding diagnosis of acute nonlymphocytic leukemia by 2 years in a patient with multiple myeloma without cytological evidence of myelodysplasia

A case of acute nonlymphocytic leukemia (ANLL) occurring 2 years after the diagnosis of multiple myeloma (MM) that had been treated by only one course of melphalan/prednisone chemotherapy is reported. Cytogenetic and fluorescence in situ hybridization analysis of peripheral blood cells revealed trisomy 8 as the sole cytogenetic defect at the time of diagnosis of ANLL. Two years earlier, when MM was diagnosed without any cytological evidence of co-existent myelodysplasia, chromosomal analysis of bone marrow cells showed the same pathological karyotype 47, XY, +8 in 14 of 20 mitoses studied. Our interpretation of this unusual cytogenetic finding is that at the time of diagnosis of MM, in spite of lacking cytological signs of myelodysplasia, an unrecognizable myelodysplastic syndrome must have been present which then evolved to ANLL.

Double autosomal/gonosomal mosaic aneuploidy: study of nondisjunction in two cases with trisomy of chromosome 8

We report cytogenetic and molecular investigations performed in two cases of mosaic trisomy 8 combined with mosaic sex chromosome aneuploidy. In a 35-year-old female, presenting with short stature, gonadal dysgenesis, and a multiple congenital anomalies/mental retardation syndrome typical of trisomy 8, chromosome analysis from peripheral lymphocytes showed the presence of three cell lines, whose karyotypes were 45,X (59.2%), 46,X,+8 (1.2%), and 47,XX,+8 (39.6%), respectively. The same cell lines were found in a skin fibroblast culture, though in different proportions. The second patient, a 9-month-old male with multiple skeletal abnormalities, showed a 47,XY,+8 and a 47,XXY cell line in both peripheral lymphocytes (61.7% and 38.3%, respectively) and skin fibroblasts (92.8% and 7.2%, respectively). To determine the events underlying the origin of these complex karyotypes we performed Southern blot and polymerase chain reaction (PCR) analysis using polymorphic DNA markers from the X chromosome and from chromosome 8. Both supernumerary chromosomes 8, and, in case 2, the two X chromosomes, appeared to be identical, lacking detectable recombination events. We conclude that, in both cases, the most likely mechanism underlying the origin of the mosaic cell lines was formation of a normal zygote, followed by mitotic errors during early divisions.

Identification of a small supernumerary ring chromosome 8 by fluorescent in situ hybridization in a child with developmental delay and minor anomalies

We report a 15-month-old female with developmental delay, hypotonia, and minor anomalies whose karyotype is 47,XX,+r. Due to its small size, the origin of the ring chromosome was indeterminate by standard G-banded karyotyping. Fluorescent in situ hybridization was performed, which indicated that the ring chromosome was derived from the pericentric region of chromosome 8.

Natural history of the recombinant (8) syndrome

The recombinant 8[Rec(8)] syndrome [rec(8), (8qter-->8q22.1::8p23.1-->8qter] is due to a parental inv(8)(8pter-->8p23.1::8q22.1-->8p23.1::8q22+ ++.1-->8qter). All inv(8) parents we have studied were of Hispanic origin. The Rec(8) phenotype consists of a characteristic set of minor facial anomalies, cardiovascular and other major malformations, and moderate to severe mental retardation. The clinical phenotype is relatively consistent in all published cases; however the natural history of the condition has remained unknown. Retrospective and prospective information on 42 propositi, spanning a period from 5 days to 23 years, allowed us to define the natural history of this syndrome, tabulate the frequency and the evolution of phenotypic abnormalities, and share our experience with different therapeutic approaches.

Atypical chronic myelogenous leukemia in a patient with trisomy 8 mosaicism syndrome

A 17-year-old woman was admitted for bone marrow transplantation with the diagnosis of atypical Philadelphia-negative chronic myelogenous leukemia (aCML), cytogenetically characterized by trisomy 8 as the sole chromosome aberration. A striking feature was a congenital opacity of the right cornea. Chromosomal analysis of skin fibroblasts were performed and revealed a mosaic for trisomy 8. Commonly, a distinct clinical picture leads to the diagnosis of trisomy 8 mosaicism syndrome (T8ms), but an extreme phenotypic variability has been observed. To our knowledge the development of an aCML in a patient with T8ms has not been reported. A review of the literature revealed that an association to other hematological disorders had been described in two cases. The question of whether our patient's aCML was a random event or not is discussed. The patient is now 24 months post transplant and shows no evidence of disease. Her Karnofsky score is 100%. We conclude that it might be worthwhile to look for an associated constitutional trisomy 8 mosaicism in all patients with trisomy 8 leukemia.

Leiomyosarcoma in a patient with trisomy 8 mosaicism

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