Isochromosome not translocation in trisomy 21q21q

Grasso, Marina; Uzielli, Maria Luisa Giovannucci; Pierluigi, Mauro; Tavellini, F.; Perroni, L; Bricarelli, Franca Dagna

doi:10.1007/bf00210673

Cited by 32 publications

(32 citation statements)

References 5 publications

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“…The origin of the trisomy has been determined in a total of 7 t(13;13) trisomy 13 cases using molecular polymorphisms, four of which have been maternal and three paternal in origin [present study (2 cases); Hassold et al, 1987 (1 case); Shaffer et al, 1994 (4 cases)]. Similarly, studies on the origin of t(21;21) chromosomes ascertained through trisomy 21 indicate that these are usually isochromosomes, and an approximately equal ratio of maternally to paternally derived cases was found [Grasso et al, 1989;Antonarakis et al, 1990;Shaffer e t al., 1991, 19931. Most isochromosomes have shown no evidence of recombination, consistent with a postmeiotic origin.…”

Section: Resultssupporting

confidence: 54%

Molecular studies of translocations and trisomy involving chromosome 13

et al. 1996

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Twenty‐four cases of trisomy 13 and one case with disomy 13, but a de novo dic(13,13) (p12p12) chromosome, were examined with molecular markers to determine the origin of the extra (or rearranged) chromosome. Twenty‐one of 23 informative patients were consistent with a maternal origin of the extra chromosome. Lack of a third allele at any locus in both paternal origin cases indicate a somatic duplication of the paternal chromosome occurred. Five cases had translocation trisomy: one de novo rob(13q14q), one paternally derived rob(13q14q), two de novo t(13q13q), and one mosaic de novo t(13q13q)/r(13). The patient with a paternal rob(13q14q) had a maternal meiotic origin of the trisomy; thus, the paternal inheritance of the translocation chromosome was purely coincidental. Since there is not a significantly increased risk for unbalanced offspring of a t(13q14q) carrier and most trisomies are maternal in origin, this result should not be surprising; however, it illustrates that one cannot infer the origin of translocation trisomy based on parental origin of the translocation. Lack of a third allele at any locus in one of the three t(13q13q) cases indicates that it was most likely an isochromosome of postmeiotic origin, whereas the other two cases showed evidence of recombination. One balanced (nontrisomic) case with a nonmosaic 45,−13,−13,t(13;13) karyotype was also investigated and was determined to be a somatic Robertsonian translocation between the maternal and paternal homologues, as has been found for all balanced homologous Robertsonian translocations so far investigated. Thus, it is also incorrect to assume in de novo translocation cases that the two involved chromosomes are even from the same parent. Despite a maternal origin of the trisomy, we cannot therefore infer anything about the parental origin of the chromosomes 13 and 14 involved in the translocation in the de novo t(13q14q) case nor for the two t(13;13) chromosomes showing a meiotic origin of the trisomy. © 1996 Wiley‐Liss, Inc.

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Section: Resultssupporting

confidence: 54%

Molecular studies of translocations and trisomy involving chromosome 13

et al. 1996

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“…The syndromic effects in those cases were probably due to UPD rather than deletion-based, as has been shown in a recent case of Angelman syndrome with t( 15;15) [Malcolm et al, 19911. This likelihood of isodisomy in these cases is enhanced by evidence that most homologous 21;21 Robertsonian translocations in Down syndrome are true molecular isochromosomes [Antonarakis et al, 1990;Grasso et al, 1989;Shaffer et al, 19921. Thus, balanced homologous Robertsonian translocation carriers appear t o be a good source for cases of UPD, although 14;14 carriers are the least common [Therman et al, 19891.…”

Section: Discussionmentioning

confidence: 96%

Uniparental isodisomy of chromosome 14 in two cases: An abnormal child and a normal adult

et al. 1995

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Uniparental disomy (UPD) of a number of different chromosomes has been found in associated with abnormal phenotypes. A growing body of evidence for an imprinting effect involving chromosome 14 has been accumulating. We report on a case of paternal UPD of chromosome 14 studied in late gestation due to polyhydramnios and a ventral wall hernia. A prenatal karyotype documented a balanced Robertsonian 14:14 translocation. The baby was born prematurely with hairy forehead, retrognathia, mild puckering of the lips and finger contractures. Hypotonia has persisted since birth and at age one year, a tracheostomy for laryngomalacia and gastrostomy for feeding remain necessary. Absence of maternal VNTR polymorphisms and homozygosity of paternal polymorphisms using chromosome 14 specific probes at D14S22 and D14S13 loci indicated paternal uniparental isodisomy (pUPID). Parental chromosomes were normal. We also report on a case of maternal UPD in a normal patient with a balanced Robertsonian 14:14 translocation and a history of multiple miscarriages. Five previous reports of chromosome 14 UPD suggest that an adverse developmental effect may be more severe whenever the UPD is paternal in origin. This is the second reported patient with paternal UPD and the fifth reported with maternal UPD, and only few phenotypic similarities are apparent. Examination of these chromosome 14 UPD cases of maternal and paternal origin suggests that there are syndromic imprinting effects.

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“…On the cytogenetic level, it was not possible to distinguish an isochromosome i(13q) from a Robertsonian translocation of two homologous chromosomes 13. DNA studies of trisomy 21 due to de novo rea(21q;21q) have concluded that the majority is due to isochromosomes i(21q) and not translocations between two chromosomes 21 [14][15][16][17]. Similar [18][19][20][21].…”

Section: Discussionmentioning

confidence: 94%

“…Robertsonian translocations are the most common human structural chromosomal abnormalities with an incidence of 1.23/ 1000 live births [5,6]. They are mainly observed in group D chromosomes (i.e., 13,14,15) and group G (i.e., 21 and 22). The D/D translocation is the most frequent type, with a high predominance of 13;14 translocations [6,7].…”

Section: Introductionmentioning

confidence: 99%

Prenatal Diagnosis of Translocation 13;13 Patau Syndrome: Clinical Features of Two Cases

Pazarbaşı¹,

Demırhan²,

Süleymanova-Karahan³

et al. 2008

Balkan Journal of Medical Genetics

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Patau syndrome is associated with extra chromosome 13 material, either free as in the 47,+13 or in a Robert sonian translocation or another rearrangement. We report on two fetuses with trisomy 13 who were diagnosed prenatally via cord blood and amniocentesis, respectively. They showed de novo Robertsonian translocation between chromosome 13 and 13, and had normal parents. One was detected cytogeneticaly at 24 weeks of gestation with a karyotype of 46,XX, rob(13;13) and lived only 1 month after birth. Holoprosencephaly, proboscis, microphthalmia and heart septal defects were present. The other fetus was examined at 14 weeks gestation because of cystic hy groma, hydrothorax and hyperechogenic kidneys and had the karyotpe 46,XY, rob(13;13). After abortion the fetus was found to have a cleft lip and palate, postaxial poly dactyly of the feet, micrognathia, omphalocele, low-set ears with abnormal helix and to be small for the gestational age. Due to the difference in chromosomal makeup seen in non disjunction, there may be differences in expression of several of the features often seen with trisomy 13, either classical type (as in the 47,+13) or de novo Robertsonian translocation type (as in the 46).

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Isochromosome not translocation in trisomy 21q21q

Cited by 32 publications

References 5 publications

Molecular studies of translocations and trisomy involving chromosome 13

Molecular studies of translocations and trisomy involving chromosome 13

Uniparental isodisomy of chromosome 14 in two cases: An abnormal child and a normal adult

Prenatal Diagnosis of Translocation 13;13 Patau Syndrome: Clinical Features of Two Cases

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