A three-year follow-up on a child with low level trisomy 8 mosaicism which was diagnosed prenatally

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.

Trisomy 8 mosaicism in the placenta: A Danish cohort study of 37 cases and a literature review

OBJECTIVE

To evaluate the risk of fetal involvement when trisomy 8 mosaicism (T8M) is detected in chorionic villus samples (CVS).

METHODS

A retrospective descriptive study of registered pregnancies in Denmark with T8M in CVS identified through a database search and a review of published cases of T8M found through a systematic literature search and inclusion of cross references. Pregnancies with T8M in CVS and no additional numerical chromosomal aberrations were included.

RESULTS

A total of 37 Danish cases and 60 published cases were included. T8M detected in a CVS was associated with fetal involvement in 18 out of 97 pregnancies (18.6% [95%CI: 11.4-27.7]). Eight out of 70 (11.4% [95%CI: 5.1-21.3]) interpreted prenatally to be confined placental mosaicism (CPM) were subsequently found to be true fetal mosaicisms (TFM).

CONCLUSION

T8M detected in CVS poses a significant risk of fetal involvement, and examination of amniotic fluid (AF) and/or fetal tissue should be offered. However, a normal result of AF still has a considerable residual risk of fetal involvement. Genetic counselling at an early gestational age is essential, and follow-up ultrasonography should be performed to predict fetal involvement if possible.

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.

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.

Management of prenatally detected trisomy 8 mosaicism

We report on ten pregnancies with trisomy 8 mosaicism. Nine cases were prenatally detected in chorionic villi (n=6), amniotic fluid (AF) cells (n=2) or fetal blood (FB) lymphocytes (n=1). Follow-up laboratory investigations showed confined placental mosaicism (CPM) or pseudomosaicism in eight cases. In one case with ultrasound abnormalities, trisomy 8 mosaicism was detected in FB cells although cultured AF cells showed normal cells only. Another case of mosaic trisomy 8 was prenatally missed; cytogenetic analysis of short-term cultured villi revealed a normal male karyotype, while postnatally, trisomy 8 mosaicism was detected in peripheral blood lymphocytes and skin fibroblasts of the affected child. These findings indicate the difficulties in the prenatal diagnosis of trisomy 8 mosaicism. When found in chorionic villi, it mostly represented CPM, while in a case of true fetal trisomy 8 mosaicism, the cytotrophoblast cells showed a normal karyotype. So, the cytotrophoblast compartment of chorionic villi is a poor indicator of the presence or absence of fetal trisomy 8 mosaicism. Follow-up investigations including amniocentesis and especially fetal blood sampling are required to come to a definite prenatal diagnosis of trisomy 8 mosaicism.

Prenatal diagnosis of mosaic trisomy 8 in a fetus with normal nuchal translucency thickness and reversed end-diastolic ductus venosus flow

We report a case of the prenatal diagnosis of trisomy 8 in a fetus presenting with normal nuchal translucency of 0.8 mm and reversed end-diastolic ductus venosus blood flow at a routine first-trimester scan at 11 weeks of gestation. No structural abnormalities were detected by the ultrasound scan. Karyotyping by chorionic villus sampling led to the diagnosis of mosaic trisomy 8, which was confirmed by fluorescent in-situ hybridization on fetal tissue samples.

Accuracy of cytogenetic findings on chorionic villus sampling (CVS)--diagnostic consequences of CVS mosaicism and non-mosaic discrepancy in centres contributing to EUCROMIC 1986-1992

Of 62,865 karyotyped chorionic villus (CV) samples that were reported to EUCROMIC 1986-1992, 98.5 per cent showed either a normal karyotype (true negative result; 94.8 per cent of the total) or a non-mosaic chromosomal aberration (true positive non-mosaic result; 3.7 per cent). True fetal mosaicism was diagnosed in about 0.15 per cent of the 62,865 CV samples, while confined placental mosaicism (CPM) occurred in 1.0 per cent. False-positive non-mosaic aberrations were observed in 0.15 per cent and false-negative CVS (chorionic villus sampling) results in only 0.03 per cent. The remaining 0.15 per cent of the CVS results were unclassifiable. These figures determined a sensitivity of CVS for prenatal detection of chromosome aberrations of 98.9-99.6 per cent (95 per cent confidence intervals), a specificity of 98.5-98.8 per cent, a positive predictive value of 72.6-78.3 per cent, and a negative predictive value of 99.95-99.98 per cent. False-positive non-mosaic aberrations that could not from the outset be suspected of being confined to the placenta were very rare (0.07 per cent of CV samples). They most often involved non-mosaic monosomy X and trisomy 18 encountered after direct preparation alone. False-negative CVS results were extremely rare (0.03 per cent) and occurred, with only one exception, after direct preparation alone. Thirteen of the 19 false-negative CVS diagnoses were from pregnancies at a particularly high risk for fetal chromosomal aberration. Seventy-five per cent of the pregnancies with CVS mosaicism or non-mosaic discrepancy and known outcome continued to livebirth. When CVS mosaicism was encountered, the definitive prenatal cytogenetic diagnosis was most often obtained through subsequent amniocentesis. However, the use of amniocentesis and the frequency of pregnancy termination depended on the type of chromosomal aberration involved. We conclude that CVS is an accurate method for prenatal chromosome analysis. In pregnancies at high risk for fetal chromosomal abnormality, we recommend, however, not relying solely on a normal karyotype obtained after direct preparation alone.

Constitutional trisomy 8 as first mutation in multistep carcinogenesis: clinical, cytogenetic, and molecular data on three cases

Three patients, with constitutional trisomy 8 mosaicism (CT8M), who developed a malignancy are reported. The diagnoses were refractory anaemia, acute lymphoblastic leukaemia, and idiopathic myelofibrosis. In the child with acute leukaemia, the CT8M was diagnosed at birth due to severe dysmorphisms and malformations; the other two patients showed a milder phenotype, and the CT8M was diagnosed only after the finding of trisomy 8 in neoplastic cells. The review of eight similar, previously reported cases and the clinical, cytogenetic, and molecular studies performed in our patients led us to make the following observations: (I) CT8M predisposes to neoplasms, preferentially to myelo- or lymphoproliferative diseases; (2) a gene dosage effect for glutathione reductase in red blood cells was seen in two of our patients; (3) the wide phenotypic variation of CT8M was confirmed: trisomy 8 in neoplastic cells of phenotypically near-normal cases may be misinterpreted as acquired; and (4) molecular studies suggested a postzygotic origin of the trisomy in our three cases, with the supernumerary chromosome being of paternal origin in one case and of maternal origin in the other two. We postulate that the trisomy 8 in neoplasms may often occur by mitotic nondisjunction in an early embryonic multipotent cell and that what is usually interpreted as an acquired trisomy 8 may in fact be CT8M. The constitutional trisomy 8 would act as a pathogenetically important first mutation in multistep carcinogenesis. Whenever trisomy 8 is found in malignancies, the patient should be reevaluated clinically to exclude CT8M, and CT8M patients should be monitored for the possible development of malignancies.

Prenatal diagnosis of trisomy 8 mosaicism in CVS after abnormal ultrasound findings at 12 weeks

We describe a case of trisomy 8 mosaicism in which fetal chromosome analysis was prompted by ultrasound abnormalities, i.e., hygroma colli and dilatation of the renal pelves. Chorionic villus sampling (CVS) was performed, with a false-negative result on direct karyotype analysis, although cultured trophoblasts revealed trisomy 8 mosaicism. Fetal autopsy confirmed the abnormalities found on ultrasound examinations and fetal tissue examination showed different levels of trisomy 8 mosaicism. To our knowledge, this is the first prenatal diagnosis of trisomy 8 made on ultrasound findings.

Trisomy 8 mosaicism in chorionic villus sampling: case report and counselling issues

We report an unusual case involving chorionic villus sampling (CVS) and trisomy 8 mosaicism. CVS showed a normal direct preparation while the culture showed mosaicism for trisomy 8. Subsequent amniocentesis revealed only normal chromosomes. A peripheral blood culture after birth revealed low-level trisomy 8 mosaicism. The patient appeared phenotypically and developmentally normal at 30 months of age. We conclude that prenatal counselling for similar cases needs to include the rare but real possibility that chromosome mosaicism detected prenatally may be found postnatally with largely unknown consequences. Secondly, low-level chromosomal mosaicism may be more common than previously recognized. Thirdly, very low-level trisomy 8 mosaicism may be compatible with a normal phenotype but long-term follow-up is required. And lastly, the use of fetal blood sampling is questionable in these cases because the phenotype may not be accurately predicted. Further studies of such cases are needed to address these important and unanswered issues, including the potential implication of mosaicism on academic performance and cognitive functioning.

Fluorescent in situ hybridization (FISH): a new application in the delineation of true vs. pseudomosaicism in prenatal diagnosis

Metaphase chromosomes and interphase nuclei from nine amniotic fluid cultures were studied with fluorescence in situ hybridization (FISH). The samples were initially analyzed with routine G-banding and were diagnosed as having true mosaicism (five patients) or pseudomosaicism (four patients). In our study, FISH analysis could provide additional information to distinguish pseudo- from true mosaicism by allowing interphase studies and analysis of an increased number of metaphase spreads. These results suggest a multilinear origin of 'in situ' colonies of cells.