Prenatal diagnosis of mosaicism for a del(22)(q13)

Riegel, Mariluce; Baumer, Alessandra; Wisser, Josef; Acherman, Josef; Schinzel, Albert

doi:10.1002/(sici)1097-0223(200001)20:1<76::aid-pd752>3.0.co;2-m

Cited by 18 publications

(4 citation statements)

References 19 publications

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“…Somatic mosaicism for structural chromosome abnormalities is a well-recognized but rarely reported phenomenon and has been described for a number of syndromes, including 22q13 deletion (Riegel et al 2000;Phelan et al 2001), neurofibromatosis type 1 (Ainsworth et al 1997;Tinschert et al 2000), 22q11.3 deletion (Kasprzak et al 1998), dystrophin (Bunyan et al 1995), 1p36.33 deletion (Eugster et al 1997), Angelman syndrome 15q11-13 deletion (Tekin et al 2000), and 19q13.33 deletion (Mikelsaar et al 2001). Molecular confirmations of germline mosaicisms for deletions of 22q11.2 (Hatchwell et al 1998) and Williams-Beuren syndrome (Kara-Mostefa et al 1999) have also been reported.…”

Section: Mosaicism For Cryptic Deletion In Two Patients With the Anirmentioning

confidence: 99%

Frequent Chromosome Aberrations Revealed by Molecular Cytogenetic Studies in Patients with Aniridia

Crolla

Heyningen

2002

The American Journal of Human Genetics

133

109

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Seventy-seven patients with aniridia, referred for cytogenetic analysis predominantly to assess Wilms tumor risk, were studied by fluorescence in situ hybridization (FISH), through use of a panel of cosmids encompassing the aniridia-associated PAX6 gene, the Wilms tumor predisposition gene WT1, and flanking markers, in distal chromosome 11p13. Thirty patients were found to be chromosomally abnormal. Cytogenetically visible interstitial deletions involving 11p13 were found in 13 patients, 11 of which included WT1. A further 13 patients had cryptic deletions detectable only by FISH, 3 of which included WT1. Six of these, with deletions <500 kb, share a similar proximal breakpoint within a cosmid containing the last 10 exons of PAX6 and part of the neighboring gene, ELP4. Two of these six patients were mosaic for the deletion. The remaining four had chromosomal rearrangements: an unbalanced translocation, t(11;13), with a deletion including the WAGR (Wilms' tumor, aniridia, genitourinary abnormalities, and mental retardation) region, and three balanced rearrangements with what appear to be position effect breakpoints 3' of PAX6: (a) a t(7;11) with the 11p13 breakpoint approximately 30 kb downstream of PAX6, (b) a dir ins(12;11) with a breakpoint >50 kb from PAX6, and (c) an inv(11)(p13q13) with a breakpoint >75 kb downstream of PAX6. The proportion and spectrum of chromosome anomalies in familial (4/14, or 28.5%) and sporadic (26/63, or 41%) cases are not significantly different. An unexpectedly high frequency of chromosomal rearrangements is associated with both sporadic and familial aniridia in this cohort.

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Section: Mosaicism For Cryptic Deletion In Two Patients With the Anirmentioning

confidence: 99%

Frequent Chromosome Aberrations Revealed by Molecular Cytogenetic Studies in Patients with Aniridia

Crolla

Heyningen

2002

The American Journal of Human Genetics

133

109

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“…Despite a lack of phenotypic similarity to VCFS/DGS, a number of microdeletions were identified fortuitously by the absence of signal from the 22q13 control probe from commercially available VCFS/DGS fluorescence in situ hybridisation (FISH) probe kits. [5][6][7][8] A percentage of 22q13 deletions are the result of unbalanced translocations and therefore their phenotype is complicated by the presence of duplicated material from a second chromosome (8/37 patients 4 ). Deletions of 22q13 are also associated with ring chromosome 22,9 which is usually complicated by mosaicism of the r (22).…”

mentioning

confidence: 99%

Molecular characterisation of the 22q13 deletion syndrome supports the role of haploinsufficiency of SHANK3/PROSAP2 in the major neurological symptoms

Wilson

Wong²,

Shaw³

et al. 2003

Journal of Medical Genetics

344

325

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“…Apart from patients with r(22) chromosomes,14-17 mosaicism for del(22)(q13) has so far been described in a 5.5-year-old girl with global developmental delay, epilepsy, and mild facial dysmorphisms,18 and in two fetuses it was prenatally diagnosed because of ultrasound anomalies19 and increased risk of Down’s syndrome determined by maternal serum screening 4. To the best of our knowledge, Case 1 represents the first patient with 22q13.3 deletion syndrome associated with a complex mosaic chromosome rearrangement consisting of a 22q13.2-qter chromosome deletion in 45% of her cells, and an apparently normal cell line that actually carries a 22q13 segmental paternal UPD in 55% of the cells.…”

Section: Discussionmentioning

confidence: 97%

Mosaic 22q13 deletions: evidence for concurrent mosaic segmental isodisomy and gene conversion

et al. 2008

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Although 22q terminal deletions are well documented, very few patients with mosaicism have been reported. We describe two new cases with mosaic 22q13.2-qter deletion, detected by karyotype analysis, showing the neurological phenotype of 22q13.3 deletion syndrome. Case 1 represents an exceptional case of mosaicism for maternal 22q13.2-qter deletion (45% of cells) and 22q13.2-qter paternal segmental isodisomy (55% of cells). This complex situation was suspected because cytogenetic, FISH and array-CGH analyses showed the presence of an 8.8 Mb mosaic 22q13.2-qter deletion, whereas microsatellite marker analysis was consistent with maternal deletion without any evidence of mosaic deletion. Molecular analysis led to the definition of very close, but not coincident, deletion and uniparental disomy (UPD) break points. Furthermore, we demonstrated that the segmental UPD arose by gene conversion in the same region. In Case 2, mosaicism for a paternal 8.9 Mb 22q13.2-qter deletion (73% of cells) was detected. In both patients, the level of mosaicism was also verified in saliva samples. We propose possible causative mechanisms for both rearrangements. Although the size of the deletions was quite similar, the phenotype was more severe in Case 2 than in Case 1. As maternal UPD 22 has not been generally associated with any defects and as the size of the deletion is very similar in the two cases, phenotype severity is likely to depend entirely on the degree of mosaicism in each individual.

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Prenatal diagnosis of mosaicism for a del(22)(q13)

Cited by 18 publications

References 19 publications

Frequent Chromosome Aberrations Revealed by Molecular Cytogenetic Studies in Patients with Aniridia

Frequent Chromosome Aberrations Revealed by Molecular Cytogenetic Studies in Patients with Aniridia

Molecular characterisation of the 22q13 deletion syndrome supports the role of haploinsufficiency of SHANK3/PROSAP2 in the major neurological symptoms

Mosaic 22q13 deletions: evidence for concurrent mosaic segmental isodisomy and gene conversion

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