Uniparental disomy (UPD) occurs when a person receives two copies of a chromosome, or of part of a chromosome, from one parent and no copy from the other. The GeneDx Prenatal Targeted Array is a combined CGH and SNP array for detecting copy number changes and uniparental disomy (UPD), respectively. RESULTADOS: a análise molecular da região 7p11 excluiu a dissomia uniparental para este caso. No exame físico foram constatados os principais sinais.

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Skip to main content. Log In Sign Up. In most cases, the normal development on sonographic examination raised the doubt about the abnormal fetal karyotype. Placental confined mosaicism seems to be the most frequent of chromosome anomalies, fetal karyotype analysis by cause of such discrepant results.

The interpretation of fetal karyotype chorionic villus sampling CVS has been increasingly results should always be correlated with sonographic and clinical findings. Since it is performed between the 11th and the 14th weeks, CVS allows an earlier diagnosis compared Keywords: Prenatal diagnosis; Karyotyping; Mosaicism; Chorionic to amniocentesis, which is usually performed only after villus sampling; Amniocentesis; Uniparental disomy; Case reports 15 weeks.

The main indications for its performance are: Carolina Leite Drummond — Avenida Ibijau, 83 — apto. Jul 8, — Accepted: Mar 11, einstein.

UPD can manifest itself clinically as a result of the result can take ten to 20 days. The association of the imprinting phenomenon or by originating recessive both methods allows reducing the risks of false-positive diseases and, consequently, fetal anomalies or mental and false-negative results of each technique, besides retardation In most cases this alteration is present only in the placenta, not being identified in the fetus This situation is named confined placental mosaicism METHODS CPM and can be associated by the end of pregnancy Six cases of discrepant results between cytogenetics with growth restriction without an apparent cause and clinical and sonographic findings were evaluated.

It is worth alteration is present both in the placental tissue and in pointing out that the karyotypes were performed the fetus.

The and by amniocentesis is the presence of uniparental patient was referred due to a diagnosis of symmetrical disomy UPD. UPD can occur in one third of cases of fetal intrauterine growth restriction IUGR at 31 mosaicism and can be explained by the trisomy rescue weeks, observed since the 18th week. The nuchal mechanism, when the chromosomes that remain in translucency measure at 13 weeks was 1.

At the diploid fetus are both inherited from one of the 31 weeks, the amount of amniotic fluid was normal, Tabela 1. Ultrasound echocardiogram revealed the presence of cardiac at 12 weeks revealed nuchal translucency of 6.

A chorionic villus biopsy performed and, upon needle withdrawal, chorionic was performed and revealed a normal karyotype villus was collected. In dissomja placenta, 15 cells were 46, XX.

A molecular study of a Doppler flow measurement without alterations. The originand this diagnosis was confirmed in peripheral newborn, a female, weighed 2, g and presented blood collected after delivery. The mother developed a syndromic facies, but the parents chose not to severe pre-eclampsia from the 32nd week on presence perform any additional tests. At two months of age, of maternal asciteswhich indicated a premature the unipxrental suffered cardiorespiratory arrest at home delivery at 35 weeks.

The newborn, a female, weighed and recovered. Uniparenhal The child is developing with recurrent pneumonias growth and neuropsychomotor development are a total of three and is currently alive and aged six normal, according to the assisting pediatrician.


Orphanet: Dissomia uniparental de origem paterna cromossoma 6

Karyotype analysis of the parents showed normal results in both. Case 2 Case 4 Female patient, aged 32 years, G I. Chorionic villus visualized and the nuchal translucency measurement sampling was indicated and the resulting karyotype was 1. Amniocentesis was performed at 14 weeks gestation, with edema of the subcutaneous tissues, and six days, and the following structural alterations ascites and pleural effusion.

A fetal echocardiogram were detected: The fetal echocardiogram was 18, in 15 analyzed cells. Delivery by C-section was indicated at 41 normal.

On ultrasound follow-up, the fetus presented weeks, and the newborn, a female, weighed 3, g. Placental to a new amniocentesis, which resulted in a 46,XY histopathology was normal. The child follow-up to the karyotype.

The pregnancy progressed uneventfully and age of four months showed normal neuropsychomotor the newborn, a male, was born at 38 weeks and five development, according to information from the days of gestation, weighing 3, g, measuring 48 cm, pediatrician.

Several fragments of the placenta From the experience of a renowned laboratory and peripheral blood were sent for karyotyping, and in the United States, the authors reported 62 cases the results were also normal.

Of these 62 cases, 18 were Female patient, aged 37 years, G II, P I, referred at 12 true biological discrepancies, 14 due to failure in weeks and two days for suspected fetal omphalocele sex identification on the ultrasound, eight involved containing liverwhich was confirmed. The nuchal multiple gestations, 12 were typing errors, and six due translucency measurement was 1.

Follow-up of this pregnancy was lost omphalocele in case 5. Increase in nuchal translucency thereafter. When none of these alterations is present in the fetus, it is difficult Case 6 to find an etiology to explain such an increase. It is Female patient, aged 30 years, G II, P I, referred at 13 known that fluid accumulation in the nuchal region, weeks and five days for increase in nuchal translucency, which occurs in a transient manner during this phase, which measured 2.

A chorionic villus measurement. A fetal echocardiogram and further increased nuchal translucency and mosaicism was control sonograms were normal. A peripheral prenatal karyotype However, the possible causes dissommia blood karyotype was obtained revealing a mosaic 46,XX this association dissomis not clear yet. Abdominal ultrasound and echocardiogram were karyotype, and no malformations were found either normal. The dssomia is currently 15 days old.

Its occurrence in infrequent, may occur in clinical practice. Therefore, other fetal tissues or placenta, however, is the rarest In a large study alteration, leading to performing the procedure. Apparently, the dissomix uniparental disomy, there seems dissokia be an even earlier the gestational age, in which placental analysis more negative effect on fetal growth This theory is performed, the greater the chance of finding a could explain the severe progression of case 1, with chromosomal anomaly.

False-negative CVS results have fetal growth restriction associated to maternal pre- an incidence of 0. In a review of Apparently, the higher the level dissomiaa aneuploidy 10, chorionic villus biopsies, three cases were found found in the placental tissue, the greater the risk of with a normal result in the direct study, corrected by fetal repercussion.

As a rule, the aspect most commonly the culture result. Even more rarely, a false-negative affected in these cases is fetal growth, which may occur result can be found in culture too In general, infrequent chromosome anomaly on CVS analysis, unipafental kind disomia mosaicism, called pseudomosaicism, does which would normally be incompatible with normal not reflect a true fetal mosaicism.


In these cases, the fetal development. Especially in such cases, ultrasound chromosomal alteration can have occurred during cell follow-up and complementary analyses of the fetal division in vitro, i. The discrepancy karyotype in amniotic fluid along with UPD investigation found in case 4, in which the fetal unipwrental was abnormal seem to be essential for the elucidation of the fetal in the first amniocentesis and normal in the second, can diagnosis, since in both cases the postnatal findings be explained by a smaller number of cells analyzed or were compatible with normal newborns.

In case 6, by failure to detect the mosaicism, due to the difference the favorable development of the newborn also led to in growth speed between the abnormal and the normal performing a postnatal control karyotype, showing a cells.

In this case, the possibility of mosaicism in the discrepancy between CVS and fetal blood. Considering the mosaicism found in the analysis of chorionic villus, it is prudent to keep the fetus under ultrasound follow-up and to extend the investigation 2.

This complexity of prenatal diagnosis makes development. Whenever there are discrepancies When it is complete, it usually results in a spontaneous between the clinical picture and the laboratory result, first-trimester abortion.

Uniparental disomy

Thus, when it is detected in a further diagnostic work-up and ultrasound follow-up fetus with normal development, it raises the suspicion seem to be essential for a correct management. In most of the cases the development is favorable, although there is a higher risk uniparentzl premature delivery Feasibility, the whole gestation and can then be confirmed, after accuracy and safety of chorionic villus sampling: Chromosomal mosaicism in chorionic Confined placental mosaicism and intrauterine fetal villus sampling.

Kalousek DK, Vekemans M. Cytogenetic results from unuparental U. Collaborative Study on CVS. Genomic imprinting and a case for new Diagn.

Mosaicism in chorionic villus sampling: Confined placental mosaicism as a risk factor among newborns with fetal growth restriction. Confirmation of CVS mosaicism in term placentae and high frequency of intrauterine growth retardation association with confined placental mosaicism. Meiotic origin of trisomy in confined placental mosaicism is correlated with Fetoplacental chromosomal presence of fetal uniparental disomy, high uniparentaal of trisomy in trophoblast, discrepancy.

Am J Hum Genet. Confirmation of mosaicism and jniparental disomy in amniocytes, after detection of 8. Fridman C, Koiffmann CP. Origin of uniparental disomy 15 in patients mosaic chromosome abnormalities in chorionic villi.

Eur J Hum Genet. Am J Med Genet. Clinical aspects, prenatal H, et al.

Origin of amnion and implications for evaluation of the fetal genotype diagnosis, and pathogenesis of trisomy 16 mosaicism. Chromosomal mosaicism hydropsis fetalis. Complete karyotype Guidelines for Obstetrician-Gynecologists. Prenatal diagnosis of discrepancy between placental and fetal cells in a case of ring chromosome fetal chromosomal abnormalities. A rare case of a false-negative uniparsntal Accuracy of cytogenetic findings on chorionic in both direct and culture of a chorionic uniarental sample.

Chromosome mosaicism in 6, amniocenteses.