Mosaic trisomy 17 in amniotic fluid cells not confirmed in the newborn

Djalali, Mahmoud; Barbi, Gotthold; Grab, Dieter

doi:10.1002/pd.1970110610

Cited by 18 publications

(15 citation statements)

References 15 publications

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“…Twenty such instances have been previously reported (Table I). In most of them, cytogenetic follow-up did not show any involvement of fetal(-derived) tissues leading to the proposal that trisomy 17 mosaicism is confined to extra-fetal tissues [Kalousek et al, 1987;Djalali et al, 1991]. Of those identified prenatally, most have been phenotypically normal postnatally.…”

Section: Discussionmentioning

confidence: 91%

“…The reasons for that are not well understood. Strong postzygotic selection or an extraembryonic origin of certain trisomies are each possible explanations [Djalali et al, 1991]. Multiple cell pseudo-mosaicism 17 was found in 6.1% of amniocyte cultures, which is unexpectedly frequent compared to the general incidence of 1.05% [Hsu et al, 1992].…”

Section: Discussionmentioning

confidence: 97%

“…Full trisomy 17 has never been observed in liveborns and rarely in spontaneous abortions [Hassold, 1982]. Trisomy 17 mosaicism is one of the rarest aneuploidies observed in chorionic villi and in amniocytes, and has been described so far in only 23 cases [Bullerdiek and Bartnitzke, 1982;Kalousek et al, 1987;Wilson et al, 1989;Welborn and Lewis, 1990;Djalali et al, 1991;Butler et al, 1996;Shaffer et al, 1996;Hsu et al, 1997;Djalali et al, 1998;Butler, 1999;Genuardi et al, 1999;Lesca et al, 1999;Nassar et al, 2000;Collado et al, 2003;Terhal et al, 2004;Abrams et al, 2005]. Most of these showed mosaicism in amniocytes and a normal karyotype in blood lymphocytes (n ¼ 16).…”

Section: Introductionmentioning

confidence: 94%

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Pre‐ and postnatal findings in trisomy 17 mosaicism

Utermann

Riegel

Leistritz

et al. 2006

American J of Med Genetics Pt A

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Trisomy 17 mosaicism is one of the rarest autosomal trisomies in humans. Thus far, only 23 cases have been described, most of them detected prenatally. In only five instances has mosaicism been demonstrated in lymphocytes and/or fibroblasts postnatally, and only in these have multiple congenital anomalies (MCA), facial dysmorphisms, and mental retardation been reported. Patients with trisomy 17 mosaicism at amniocentesis and a normal karyotype in blood and fibroblasts (n = 17) were always healthy. Here, we report on pre- and postnatal clinical, cytogenetic, molecular-cytogenetic, and molecular findings in four patients with trisomy 17 mosaicism. The first case was detected in cultured but not in short-term chorionic villi and amniocytes. Due to MCA on prenatal ultrasound examination the pregnancy was terminated. The second patient is a 13-month-old healthy boy, in whom low level trisomy 17 mosaicism was detected in cultured chorionic villi only. The third patient is a 2-year-old girl with growth retardation, developmental delay, MCA, and trisomy 17 mosaicism in amniocytes, fibroblasts, and placenta, but not in blood and buccal smear. The fourth patient is a 9-year-old boy with growth and mental retardation, sensoneurinal hearing loss, and MCA. Cytogenetic analyses showed trisomy 17 mosaicism in amniocytes, skin fibroblasts, and urinary sediment cells, whereas in blood and buccal smear a 46,XY karyotype was found. Molecular investigations in all four cases indicated biparental inheritance of chromosome 17. Formation of trisomy was most likely due to a maternal meiosis I error in Patient 1 and a postzygotic non-disjunction of the paternal chromosome 17 in Patient 4. Cerebellar malformations, reported in two cases from the literature and in two reported here may be a specific feature of trisomy 17 mosaicism. Since the aberration has rarely been reported in lymphocytes, chordocentesis is not indicated in prenatal diagnosis. Prenatal genetic counseling for trisomy 17 mosaicism in chorionic villi or amniocytes should consider that the clinical significance remains uncertain.

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Section: Discussionmentioning

confidence: 91%

Section: Discussionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 94%

See 1 more Smart Citation

Pre‐ and postnatal findings in trisomy 17 mosaicism

Utermann

Riegel

Leistritz

et al. 2006

American J of Med Genetics Pt A

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“…Mosaicism for trisomy 17 is a rare condition, which has been ascertained both pre-and postnatally. The few prenatally diagnosed cases have been observed in amniocytes (12 cases), [2][3][4][5][6][7][8] and, more rarely, in chorionic villus samples. 11 In all cases, no major foetal or newborn abnormalities were observed.…”

Section: Discussionmentioning

confidence: 99%

“…[2][3][4][5][6][7][8] No phenotypic abnormalities have been observed in the newborns or foetuses, and whenever additional cell types, mainly peripheral lymphocytes, were examined cytogenetically, these were shown to contain only euploid cells. On the other hand, nothing is known about the possible effects of UPD17 on embryo development, since this condition has never been described before.…”

Section: Introductionmentioning

confidence: 99%

Mosaic trisomy 17 in amniocytes: phenotypic outcome, tissue distribution, and uniparental disomy studies

et al. 1999

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Mosaicism for trisomy 17 in amniocyte cultures is a rare finding, whilst postnatal cases are exceptional. In order to gain insight into the possible effects of the distribution of the trisomic line and of uniparental disomy (UPD) on embryofoetal development, we have performed follow-up clinical, cytogenetic and molecular investigations into three newly detected prenatal cases of trisomy 17 mosaicism identified in cultured amniotic fluid. In the first case, the pregnancy ended normally with the birth of a healthy girl, and analysis of newborn lymphocytes and of multiple extra-embryonic tissues was indicative of confined placental mosaicism. The second case was also associated with a normal pregnancy outcome and postnatal development, and only euploid cells were found in peripheral blood after birth. However, maternal isodisomy 17 consequent to a meiosis II error and loss of a chromosome 17 homologue was detected in peripheral lymphocytes postnatally. In the third case, pathological examination after termination of pregnancy showed growth retardation and minor dysmorphisms, and the trisomic line was detected in foetal skin fibroblasts. In addition, biparental derivation of chromosome 17 was demonstrated in the euploid lineage. These results, together with previously reported data, indicate that true amniotic trisomy 17 mosaicism is more commonly of extra-embryonic origin and associated with normal foetal development. Phenotypic consequences may arise when the trisomic line is present in foetal tissues. Case 2 also represents the first observation of maternal UPD involving chromosome 17; the absence of phenotypic anomalies in the child suggests that chromosome 17 is not likely to be subject to imprinting in maternal gametes.

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