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Rapid screening for chromosomal aneuploidies using array-MLPA.

Yan JB, Xu M, Xiong C, Zhou DW, Ren ZR, Huang Y, Mommersteeg M, van Beuningen R, Wang YT, Liao SX, Zeng F, Wu Y, Zeng YT - BMC Med. Genet. (2011)

Bottom Line: However, results are usually not available for 3-4 days or more.Furthermore, we detected two chromosome X monosomy mosaic cases in which the mosaism rates estimated by array-MLPA were basically consistent with the results from karyotyping.Our study demonstrates the successful application and strong potential of array-MLPA in clinical diagnosis and prenatal testing for rapid and sensitive chromosomal aneuploidy screening.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Medical Genetics, Children's Hospital of Shanghai, Shanghai Jiao Tong University, Shanghai, P.R. China.

ABSTRACT

Background: Chromosome abnormalities, especially trisomy of chromosome 21, 13, or 18 as well as sex chromosome aneuploidy, are a well-established cause of pregnancy loss. Cultured cell karyotype analysis and FISH have been considered reliable detectors of fetal abnormality. However, results are usually not available for 3-4 days or more. Multiplex ligation-dependent probe amplification (MLPA) has emerged as an alternative rapid technique for detection of chromosome aneuploidies. However, conventional MLPA does not allow for relative quantification of more than 50 different target sequences in one reaction and does not detect mosaic trisomy. A multiplexed MLPA with more sensitive detection would be useful for fetal genetic screening.

Methods: We developed a method of array-based MLPA to rapidly screen for common aneuploidies. We designed 116 universal tag-probes covering chromosomes 13, 18, 21, X, and Y, and 8 control autosomal genes. We performed MLPA and hybridized the products on a 4-well flow-through microarray system. We determined chromosome copy numbers by analyzing the relative signals of the chromosome-specific probes.

Results: In a blind study of 161 peripheral blood and 12 amniotic fluid samples previously karyotyped, 169 of 173 (97.7%) including all the amniotic fluid samples were correctly identified by array-MLPA. Furthermore, we detected two chromosome X monosomy mosaic cases in which the mosaism rates estimated by array-MLPA were basically consistent with the results from karyotyping. Additionally, we identified five Y chromosome abnormalities in which G-banding could not distinguish their origins for four of the five cases.

Conclusions: Our study demonstrates the successful application and strong potential of array-MLPA in clinical diagnosis and prenatal testing for rapid and sensitive chromosomal aneuploidy screening. Furthermore, we have developed a simple and rapid procedure for screening copy numbers on chromosomes 13, 18, 21, X, and Y using array-MLPA.

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Array-MLPA analysis of chromosome X monosomy mosaicism. (A) A female patient (B10) with mosaicism. The average copy number on chromosome X was 0.71. (B) G-banding analysis revealed the patient had the karyotype 45,X/46,X,i(X)(q10). (C) A female patient (B11) with mosaicism. The average copy number on chromosome X was 0.72. (D) G-banding analysis revealed the patient had the karyotype 45,X(70%)/47,XXX (30%). Error bars represented the corresponding SD of the copy numbers on the MLPA probes covering each chromosome.
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Figure 4: Array-MLPA analysis of chromosome X monosomy mosaicism. (A) A female patient (B10) with mosaicism. The average copy number on chromosome X was 0.71. (B) G-banding analysis revealed the patient had the karyotype 45,X/46,X,i(X)(q10). (C) A female patient (B11) with mosaicism. The average copy number on chromosome X was 0.72. (D) G-banding analysis revealed the patient had the karyotype 45,X(70%)/47,XXX (30%). Error bars represented the corresponding SD of the copy numbers on the MLPA probes covering each chromosome.

Mentions: In this study, two cases (B10 and B11) with chromosome X monosomy mosaicism were identified successfully by array-MLPA (Table 2). For mosaic samples, the ratio reflects the extent of mosaicism, e.g. ratio 0.75 for a 50% chromosome X monosomy in a female sample. The results showed that the average copy numbers of chromosome X were 0.71 and 0.72 in the two samples. This suggested that approximately 50% of the sample cell population carried chromosome X monosomy. G-banded karyotype analysis showed that their chromosome karyotypes were 45,X/46,X,i(X)(q10) and 45,X/47,XXX for B10 and B11 respectively, which were basically consistent with array-MLPA results (Figure 4).


Rapid screening for chromosomal aneuploidies using array-MLPA.

Yan JB, Xu M, Xiong C, Zhou DW, Ren ZR, Huang Y, Mommersteeg M, van Beuningen R, Wang YT, Liao SX, Zeng F, Wu Y, Zeng YT - BMC Med. Genet. (2011)

Array-MLPA analysis of chromosome X monosomy mosaicism. (A) A female patient (B10) with mosaicism. The average copy number on chromosome X was 0.71. (B) G-banding analysis revealed the patient had the karyotype 45,X/46,X,i(X)(q10). (C) A female patient (B11) with mosaicism. The average copy number on chromosome X was 0.72. (D) G-banding analysis revealed the patient had the karyotype 45,X(70%)/47,XXX (30%). Error bars represented the corresponding SD of the copy numbers on the MLPA probes covering each chromosome.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3111339&req=5

Figure 4: Array-MLPA analysis of chromosome X monosomy mosaicism. (A) A female patient (B10) with mosaicism. The average copy number on chromosome X was 0.71. (B) G-banding analysis revealed the patient had the karyotype 45,X/46,X,i(X)(q10). (C) A female patient (B11) with mosaicism. The average copy number on chromosome X was 0.72. (D) G-banding analysis revealed the patient had the karyotype 45,X(70%)/47,XXX (30%). Error bars represented the corresponding SD of the copy numbers on the MLPA probes covering each chromosome.
Mentions: In this study, two cases (B10 and B11) with chromosome X monosomy mosaicism were identified successfully by array-MLPA (Table 2). For mosaic samples, the ratio reflects the extent of mosaicism, e.g. ratio 0.75 for a 50% chromosome X monosomy in a female sample. The results showed that the average copy numbers of chromosome X were 0.71 and 0.72 in the two samples. This suggested that approximately 50% of the sample cell population carried chromosome X monosomy. G-banded karyotype analysis showed that their chromosome karyotypes were 45,X/46,X,i(X)(q10) and 45,X/47,XXX for B10 and B11 respectively, which were basically consistent with array-MLPA results (Figure 4).

Bottom Line: However, results are usually not available for 3-4 days or more.Furthermore, we detected two chromosome X monosomy mosaic cases in which the mosaism rates estimated by array-MLPA were basically consistent with the results from karyotyping.Our study demonstrates the successful application and strong potential of array-MLPA in clinical diagnosis and prenatal testing for rapid and sensitive chromosomal aneuploidy screening.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Medical Genetics, Children's Hospital of Shanghai, Shanghai Jiao Tong University, Shanghai, P.R. China.

ABSTRACT

Background: Chromosome abnormalities, especially trisomy of chromosome 21, 13, or 18 as well as sex chromosome aneuploidy, are a well-established cause of pregnancy loss. Cultured cell karyotype analysis and FISH have been considered reliable detectors of fetal abnormality. However, results are usually not available for 3-4 days or more. Multiplex ligation-dependent probe amplification (MLPA) has emerged as an alternative rapid technique for detection of chromosome aneuploidies. However, conventional MLPA does not allow for relative quantification of more than 50 different target sequences in one reaction and does not detect mosaic trisomy. A multiplexed MLPA with more sensitive detection would be useful for fetal genetic screening.

Methods: We developed a method of array-based MLPA to rapidly screen for common aneuploidies. We designed 116 universal tag-probes covering chromosomes 13, 18, 21, X, and Y, and 8 control autosomal genes. We performed MLPA and hybridized the products on a 4-well flow-through microarray system. We determined chromosome copy numbers by analyzing the relative signals of the chromosome-specific probes.

Results: In a blind study of 161 peripheral blood and 12 amniotic fluid samples previously karyotyped, 169 of 173 (97.7%) including all the amniotic fluid samples were correctly identified by array-MLPA. Furthermore, we detected two chromosome X monosomy mosaic cases in which the mosaism rates estimated by array-MLPA were basically consistent with the results from karyotyping. Additionally, we identified five Y chromosome abnormalities in which G-banding could not distinguish their origins for four of the five cases.

Conclusions: Our study demonstrates the successful application and strong potential of array-MLPA in clinical diagnosis and prenatal testing for rapid and sensitive chromosomal aneuploidy screening. Furthermore, we have developed a simple and rapid procedure for screening copy numbers on chromosomes 13, 18, 21, X, and Y using array-MLPA.

Show MeSH
Related in: MedlinePlus