Mosaicism in Prader‐Willi syndrome: Detection using fluorescent in situ hybridization

Golden, Wendy L.; Sudduth, Kathy W.; Burnett, Susan H.; Kelly, Thaddeus E.

doi:10.1002/(sici)1096-8628(19990806)85:4<424::aid-ajmg22>3.3.co;2-u

Cited by 4 publications

(8 citation statements)

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“…Several individuals with somatic mosaicism for an interstitial chromosome deletion such as Smith‐Magenis syndrome [Finucane et al, 1993], 22q11 deletion [Consevage et al, 1996], and PWS [Cassidy et al, 1984; Malzac et al, 1998b; Golden et al, 1999] have been reported. Mosaicism in PWS syndrome is rare, and only a few cases have been described.…”

Section: Discussionmentioning

confidence: 99%

“…Malzac et al [1998b] reported an additional case with typical PWS clinical findings and 20% mosaicism for the deletion detected by FISH in peripheral blood lymphocytes. Recently, Golden et al [1999] reported on another child with atypical PWS findings and deletion of the SNRPN probe in 78% of peripheral lymphocytes. To the best of our knowledge, our case is the first example of a patient with FISH‐detectable mosaicism for a deletion of chromosome 15q11‐q13 and clinical findings of AS.…”

Section: Discussionmentioning

confidence: 99%

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Fluorescence in situ hybridization detectable mosaicism for Angelman syndrome with biparental methylation

et al. 2000

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We present a child with mild to moderate global developmental delay including severe speech impairment, inappropriate happy demeanor, wide-based gait, frequent ear infections with mild hearing loss, deep-set eyes, a wide mouth, widely-spaced teeth, normal head circumference, and no seizures. Results of peripheral blood lymphocyte chromosomal analysis with GTG banding were normal. However, fluorescence in situ hybridization (FISH) studies showed mosaicism for a deletion of probes (D15S10 and SNRPN) from the Angelman syndrome (AS) critical region with approximately 40% of peripheral lymphocytes having the deletion. The deleted chromosome 15 also showed centromeric duplication, which was detected with a D15Z1 probe [46,XX, dic(15)(pter-->q11.1::p11.2-->q11. 1::q13-->qter)]. The same duplication pattern was observed in 30% of the nuclei obtained from a buccal smear. Methylation studies using polymerase chain reaction with sodium bisulfite-treated DNA demonstrated a normal biparental methylation pattern. To the best of our knowledge, this is the first case with AS and a FISH detectable deletion in a mosaic pattern. We recommend FISH studies for the detection of mosaicism in the patients with AS clinical findings even if results of the methylation studies are normal.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Fluorescence in situ hybridization detectable mosaicism for Angelman syndrome with biparental methylation

et al. 2000

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“…Several recent studies have suggested the presence of mosaicism for a deletion, detected by fluorescence in situ hybridization (FISH), within chromosome 15q11‐q13 in Prader‐Willi syndrome (PWS) [Mowery‐Rushton et al, 1996; Malzac et al, 1998; Golden et al, 1999]. However, the evidence supporting mosaicism in such cases is nondefinitive, and biological considerations suggest that the putative deletion mosaicism in several of these cases is unlikely.…”

Section: To the Editormentioning

confidence: 99%

“…The “atypical PWS” case of Golden et al [1999] showed 78% of cells with a deletion using SNRPN , although D15S10 was intact in all cells. Although this represents an atypical deletion extent for PWS, it may represent one equivalent to an IC microdeletion in imprinting mutation patients [Nicholls et al, 1998].…”

Section: To the Editormentioning

confidence: 99%

Mosaicism in Prader-Willi syndrome

Nicholls

2000

Am. J. Med. Genet.

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“…Translocations, inversions or marker chromosomes involving 15q11‐q13 have rarely been reported [Schulze et al, ; Sun et al, ; Wirth et al, ; Bittel and Butler, ; Boyd et al, ]. In addition, there are reported cases with atypical and small deletions [Calounova et al, ; Sahoo et al, ; de Smith et al, ; Kanber et al, ; Duker et al, ; Kim et al, ] and deletions and imprinting defects in mosaic state [Malzac et al, ; Golden et al, ; Chaddha et al, ; Horsthemke et al, ; Boyd et al, ; Wey et al, ].…”

Section: Introductionmentioning

confidence: 99%

Small mosaic deletion encompassing the snoRNAs and SNURF‐SNRPN results in an atypical Prader–Willi syndrome phenotype

Anderlid

Lundin

Malmgren

et al. 2013

American J of Med Genetics Pt A

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Genetic analyses were performed in a male patient with suspected Prader-Willi syndrome who presented with hypogonadism, excessive eating, central obesity, small hands and feet and cognition within the low normal range. However, he had no neonatal hypotonia or feeding problems during infancy. Chromosome analysis showed a normal male karyotype. Further analysis with array-CGH identified a mosaic 847 kb deletion in 15q11-q13, including SNURF-SNRPN, the snoRNA gene clusters SNORD116 (HBII-85), SNORD115, (HBII-52), SNORD109 A and B (HBII-438A and B), SNORD64 (HBII-13), and NPAP1 (C15ORF2). MLPA confirmed the deletion and the results were compatible with a paternal origin. Metaphase-FISH verified the mosaicism with the deletion present in 58% of leukocytes analyzed. Three smaller deletions in this region have previously been reported in patients with Prader-Willi syndrome phenotype. All three deletions included SNORD116, but only two encompassed parts of SNURF-SNRPN, implicating SNORD116 as the major contributor to the Prader-Willi phenotype. Our case adds further information about genotype-phenotype correlation and supports the hypothesis that SNORD116 plays a major role in the pathogenesis of Prader-Willi syndrome. Furthermore, it examplifies diagnostic difficulties in atypical cases and illustrates the need for additional testing methods when Prader-Willi syndrome is suspected.

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Mosaicism in Prader‐Willi syndrome: Detection using fluorescent in situ hybridization

Cited by 4 publications

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Fluorescence in situ hybridization detectable mosaicism for Angelman syndrome with biparental methylation

Fluorescence in situ hybridization detectable mosaicism for Angelman syndrome with biparental methylation

Mosaicism in Prader-Willi syndrome

Small mosaic deletion encompassing the snoRNAs and SNURF‐SNRPN results in an atypical Prader–Willi syndrome phenotype

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