Clinical and molecular delineation of Tetrasomy 9p syndrome: Report of 12 new cases and literature review

Khattabi, Laïla El; Jaillard, Sylvie; Andrieux, Joris; Pasquier, Laurent; Perrin, Laurence; Capri, Yline; Benmansour, Abdelmadjid; Toutain, Annick; Marcorelles, Pascale; Vincent‐Delorme, Catherine; Journel, Hubert; Henry, Cathérine; Barace, Claire de; Devisme, Louise; Dubourg, Christèle; Démurger, Florence; Lucas, Josette; Belaud‐Rotureau, Marc‐Antoine; Amiel, Jeanne; Malan, Valérie; Blois, Marie‐Christine de; Pontual, Loïc de; Lebbar, Aziza; Dû, Nathalie Le; Germain, Dominique P.; Pinard, Jean-Marc; Pipiras, Eva; Tabet, Anne‐Claude; Aboura, Azzedine; Verloès, Alain

doi:10.1002/ajmg.a.36932

Cited by 24 publications

(67 citation statements)

References 45 publications

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“…Tetrasomy 9p is a rare chromosomal abnormality described as the presence of a supernumerary isochromosome 9p, initially found as a SMC. Further investigation of the SMC commonly shows involvement of the entire 9p, or the entire 9p with part of the heterochromatic region of 9q, or yet the entire 9p with heterochromatic region of 9q, and part of the euchromatic material of 9q [ 5 , 6 ]. Moreover, around 30% of known cases of tetrasomy 9p exhibits chromosome mosaicism.…”

Section: Introductionmentioning

confidence: 99%

Mosaic Tetrasomy of 9p24.3q21.11 postnatally identified in an infant born with multiple congenital malformations: a case report

Pinto

Minasi

Steckelberg³

et al. 2018

BMC Pediatr

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BackgroundSupernumerary Marker Chromosomes consist in structurally abnormal chromosomes, considered as an extra chromosome in which around 70% occur as a de novo event and about 30% of the cases are mosaic. Tetrasomy 9p is a rare chromosomal abnormality described as the presence of a supernumerary isochromosome 9p. Clinical features of tetrasomy 9p include a variety of physical and developmental abnormalities.Case presentationHerein, we reported a postnatal case of a newborn who died in early infancy with multiple congenital malformations due to a mosaic de novo tetrasomy 9p detected by Chromosomal Microarray Analysis. Conventional cytogenetics analysis of the proband was 47,XY,+mar[45]/46,XY[5]. The parental karyotypes presented no visible numerical or structural alterations. Microarray Analysis of the proband revealed that the marker chromosome corresponded to a mosaic de novo gain at 9p24.3q21.11.ConclusionsChromosomal Microarray Analysis was helpful to identify the origin of the supernumerary marker chromosome and it was a powerful tool to carry out genetic diagnostic, guiding the medical diagnosis. Furthermore, the CMA allowed observing at the first time in Central Brazil the tetrasomy 9p and partial tetrasomy 9q in mosaic, encompassing a large duplicated region with several morbid genes, in an infant with multiple congenital malformations.

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Section: Introductionmentioning

confidence: 99%

Mosaic Tetrasomy of 9p24.3q21.11 postnatally identified in an infant born with multiple congenital malformations: a case report

Pinto

Minasi

Steckelberg³

et al. 2018

BMC Pediatr

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“…Three of the patients described here are siblings born from parents that showed normal karyotypes in lymphocytes, which suggests that one parent is mosaic for a cell line with a normal karyotype and a cell line with the derivative chromosome 15 (der(15)t(9;15)), and that the abnormal cell line is present in the gonads. Parental mosaicism has been described for tetrasomy of 9p (El Khattabi et al, ); however, in the present case the abnormal cell line in one parent most likely either had a balanced karyotype or was trisomic for 9p.…”

Section: Discussionmentioning

confidence: 53%

“…The most common central nervous system anomalies described in patients with trisomy or tetrasomy 9p are corpus callosum anomalies and hydrocephalic conditions, most often related to Dandy Walker malformation. Dandy Walker malformation is described in 60% of fetuses diagnosed with tetrasomy 9p (El Khattabi et al, ) and 9pter‐p11.2 has been suggested as a critical region for this condition (Chen & Shih, ). Hydrocephalic conditions seem to be more common in patients with tetrasomy 9p than in patients with trisomy 9p (Norman et al, ), although the exact prevalence has not been described.…”

Section: Discussionmentioning

confidence: 99%

“…The phenotype shows great variability without a clear association to the prevalence of the abnormal cells. However, tetrasomy 9p seems to implicate more severe malformations and a worse prognosis than trisomy 9p (El Khattabi et al, ). Nonmosaic tetrasomy 9p usually results in miscarriage or early neonatal death (Dhandha, Hogge, Surti, & McPherson, ; Dutly, Balmer, Baumer, Binkert, & Schinzel, ).…”

Section: Introductionmentioning

confidence: 99%

“…Nonmosaic tetrasomy 9p usually results in miscarriage or early neonatal death (Dhandha, Hogge, Surti, & McPherson, ; Dutly, Balmer, Baumer, Binkert, & Schinzel, ). When more than one tissue type is tested, a higher frequency of tetrasomy 9p is often found in lymphocytes than in other tissues (El Khattabi et al, ).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Choroid plexus hyperplasia and chromosome 9p gains

Boxill

Becher

Sunde

et al. 2018

American J of Med Genetics Pt A

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Choroid plexus hyperplasia leading to communicating hydrocephalus is a rare disorder with only 24 patients reported so far in the literature. Furthermore, genetic information is only available for six of these cases: In one patient the condition was associated with trisomy 9p, in one patient with trisomy 9 mosaicism and in three patients with tetrasomy 9p. Here, we describe four additional patients with choroid plexus hyperplasia leading to various levels of hydrocephalus, and gain of the entire chromosome 9p region: Three with trisomy 9p and one with tetrasomy 9p. The three patients with trisomy 9p were siblings. Normal karyotypes were identified in the lymphocytes of the parents. Likely one of the parents is a mosaic for a cell line with trisomy 9p in the gonads. We demonstrate the importance of correctly diagnosing choroid plexus hyperplasia as the cause of hydrocephalus in patients with chromosome 9p gain since ventriculoperitoneal shunting is likely to fail due to intolerable formation of ascites.

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Application of various genetic analysis techniques for detecting two rare cases of 9p duplication mosaicism during prenatal diagnosis

Zhang

Zhou

Xiao

et al. 2023

Molec Gen & Gen Med

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BackgroundThe identification of genetic mosaicism and the genetic counseling needed following its discovery have been challenging problems in the field of prenatal diagnosis. Herein, we describe the clinical phenotypes and various prenatal diagnostic processes used for two rare cases of 9p duplication mosaicism and review the prior literature in the field to evaluate the merits of different methods for diagnosing mosaic 9p duplication.MethodsWe recorded ultrasound examinations, reported the screening and diagnosis pathways, and analyzed the mosaic levels of the two cases of 9p duplication using karyotype analysis, chromosomal microarray analysis (CMA), and fluorescence in situ hybridization analysis (FISH).ResultsCase 1 had a normal clinical phenotype for tetrasomy 9p mosaicism, and Case 2 showed multiple malformations caused by both trisomy 9 and trisomy 9p mosaicism. Both cases were initially suspected after non‐invasive prenatal screening (NIPT) based on cell‐free DNA. The mosaic ratio of 9p duplication found via karyotyping was lower than what was discovered by CMA and FISH, in both cases. Contrary to previous findings, the mosaic level of trisomy 9 found by karyotype analysis was greater than what was found by CMA, in terms of complex mosaicism involving trisomy 9 and trisomy 9p, in Case 2.ConclusionNIPT can indicate 9p duplication mosaicism during prenatal screening. Different strengths and limitations existed in terms of diagnosing mosaic 9p duplication by karyotype analysis, CMA, and FISH. The combined use of various methods may be capable of more accurately determining break‐points and mosaic levels of 9p duplication during prenatal diagnosis.

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Clinical and molecular delineation of Tetrasomy 9p syndrome: Report of 12 new cases and literature review

Cited by 24 publications

References 45 publications

Mosaic Tetrasomy of 9p24.3q21.11 postnatally identified in an infant born with multiple congenital malformations: a case report

Mosaic Tetrasomy of 9p24.3q21.11 postnatally identified in an infant born with multiple congenital malformations: a case report

Choroid plexus hyperplasia and chromosome 9p gains

Application of various genetic analysis techniques for detecting two rare cases of 9p duplication mosaicism during prenatal diagnosis

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