Dataset Information

A non-syndromic intellectual disability associated with a de novo microdeletion at 7q and 18p, microduplication at Xp, and 18q partial trisomy detected using chromosomal microarray analysis approach.

ABSTRACT:

Background

Chromosome abnormalities that segregate with a disease phenotype can facilitate the identification of disease loci and genes. The relationship between chromosome 18 anomalies with severe intellectual disability has attracted the attention of cytogeneticists worldwide. Duplications of the X chromosome can cause intellectual disability in females with variable phenotypic effects, due in part to variations in X-inactivation patterns. Additionally, deletions of the 7qter region are associated with a range of phenotypes.

Results

We report the first case of de novo microdeletion at 7q and 18p, 18q partial trisomy, microduplication at Xp associated to intellectual disability in a Brazilian child, presenting a normal karyotype. Karyotyping showed any chromosome alteration. Chromosomal microarray analysis detected a de novo microdeletion at 18p11.32 and 18q partial trisomy, an inherited microdeletion at 7q31.1 and a de novo microduplication at Xp22.33p21.3.

Conclusions

Our report illustrates a case that presents complex genomic imbalances which may contribute to a severe clinical phenotypes. The rare and complex phenotypes have to be investigated to define the subsets and allow the phenotypes classification.

SUBMITTER: Pinto IP

PROVIDER: S-EPMC4099144 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

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Publications

A non-syndromic intellectual disability associated with a de novo microdeletion at 7q and 18p, microduplication at Xp, and 18q partial trisomy detected using chromosomal microarray analysis approach.

Pinto Irene Plaza IP Minasi Lysa Bernardes LB da Cruz Alex Silva AS de Melo Aldaires Vieira AV da Cruz E Cunha Damiana Míriam DM Pereira Rodrigo Roncato RR Ribeiro Cristiano Luiz CL da Silva Claudio Carlos CC de Melo E Silva Daniela D da Cruz Aparecido Divino AD

Molecular cytogenetics 20140627

<h4>Background</h4>Chromosome abnormalities that segregate with a disease phenotype can facilitate the identification of disease loci and genes. The relationship between chromosome 18 anomalies with severe intellectual disability has attracted the attention of cytogeneticists worldwide. Duplications of the X chromosome can cause intellectual disability in females with variable phenotypic effects, due in part to variations in X-inactivation patterns. Additionally, deletions of the 7qter region ar ...[more]

PMID: 25028595

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Project description:BackgroundCarriers of balanced reciprocal translocation are usually phenotypically normal; however, they have an increased risk of producing gametes with chromosomal imbalance through different types of meiotic segregation of the translocation quadrivalent. The genetically imbalanced gametes when they survive can result in embryos with chromosomal abnormalities. Here we report a family with two siblings inheriting partial trisomy for 9p and 18p concurrently resulting from a 3:1 meiotic segregation of a maternal balanced translocation involving chromosome 9q and 18p, and the associated phenotype.The family - case presentationThe family was ascertained because of severe congenital anomalies in a newborn male (sibling 1). The karyotype of this patient was 47,XY,+del(9)(q13q34). Cytogenetic analysis revealed that the phenotypically normal mother harbored a balanced translocation 46,XX,t(9;18)(q13;p11.21). Chromosomal microarray analysis (CMA) of the abnormal child detected segmental trisomy for 9p and 18p. In conjunction with conventional cytogenetic results of the mother and CMA results of the affected child, the final karyotype of sibling one was 47,XY,+der(9)t(9;18) (q13;p11.22)dmat. arr[GRCh36] 9p24.3q13(199254_70163189)× 3, 18p11.32p11.22(131491_9640590)× 3; this resulted in segmental duplication of 69.96 Mb on 9pter->q13 and 9.51 Mb on 18p. There was a subsequent birth of a female sibling (sibling two) with multiple anomalies, including dysmorphic facial features, kidney aberration, cardiac defects, and abnormal brain MRI. The G-banded karyotype of this sibling was 47,XX,+del(9)(q13q34). The final karyotype of this sibling after CMA results was 47,XX,+der(9)t(9;18)(q13;p11.22)dmat. arr[GRCh37] 9p24.3p13.1(209020_38763958)× 3; 18p11.32p11.22(146484_9640912)× 3. The apparent discrepancy between the array results of the two siblings is attributed to difference in the design of array chips and genome builds used for these patients (NimbleGen/Roche v2.0 3-plex and GRCh36 for sibling one, and GGXChip + SNP array and GRCh37 of Agilent Technologies for sibling two). There are 182 OMIM genes in the duplicated region of 9p and 33 OMIM genes in the duplicated region of 18p which may have contributed to the clinical features of the affected siblings.ConclusionsTo our knowledge, we report the first two cases of concurrent partial trisomy 9p and 18p in the same family. This report adds more information about phenotypic effects of these chromosomal copy number gains and supports chromosomal microarray analysis as the standard for precise identification or demarking regions of duplications, particularly when the translocation involves at least one subterminal segment. In view of the recurring infants with congenital anomalies the couple may benefit from prenatal chromosome analysis of future pregnancies or opting to assisted reproductive methods and transferring normal embryos for implantation.

Project description:Background: Chromosomal 16p11.2 deletions and duplications are genomic disorders which are characterized by neurobehavioral abnormalities, obesity, congenital abnormalities and so on. However, the prenatal phenotypes of 16p11.2 copy number variations (CNVs) are still not well described till now. This study aimed to provide an elaborate summary of intrauterine phenotypic features for such genomic disorders. Methods: Twenty prenatal amniotic fluid samples diagnosed with 16p11.2 microdeletions/microduplications were obtained from pregnant women who opted for invasive prenatal testing. Karyotypic analysis and chromosomal microarray analysis (CMA) were performed in parallel. The pregnancy outcomes and health conditions after birth for all cases were followed up. Meanwhile, we made a pooled analysis on the prenatal phenotypes for the published cases carrying 16p11.2 CNVs. Results: 20 fetuses (20/20884, 0.10%) with 16p11.2 CNVs were identified: five 16p11.2 BP2-BP3 deletion, ten 16p11.2 BP4-BP5 deletion and five 16p11.2 BP4-BP5 duplication. Abnormal ultrasound findings were recorded in ten participants with 16p11.2 deletions.Various degrees of intrauterine phenotypic features, ranging from normal to abnormal, were observed. No ultrasound abnormalities were observed for all 16p11.2 duplication cases during the pregnancy period. For 16p11.2 deletions, eleven cases terminated their pregnancies. For 16p11.2 duplications, four cases gave birth to healthy neonates except one was lost to follow up. Conclusions: Diverse prenatal phenotypes were presented in 16p11.2 CNVs, ranging from normal to abnormal. For 16p11.2 BP4-BP5 deletion, the most common structural and non-structural abnormalities were the abnormality of the vertebral column or rib and thickened nuchal translucency, respectively. 16p11.2 BP2-BP3 deletion might be closely associated with fetal growth restriction and single umbilical artery. No representative ultrasound findings for 16p11.2 duplication were observed till now. Considering the variable expressivity and incomplete penetrance of 16p11.2 CNVs, long term follow up after birth should be carried out for these cases. We identified 20 fetuses carrying the 16p11.2 microdeletions and microduplications using chromosomal microarray analysis. And diverse prenatal phenotypes and the critical genes involved in the deleted/duplicated regions were described in this study.

Dataset Information

A non-syndromic intellectual disability associated with a de novo microdeletion at 7q and 18p, microduplication at Xp, and 18q partial trisomy detected using chromosomal microarray analysis approach.

Background

Results

Conclusions

Publications

A non-syndromic intellectual disability associated with a de novo microdeletion at 7q and 18p, microduplication at Xp, and 18q partial trisomy detected using chromosomal microarray analysis approach.

Similar Datasets

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