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An active isodicentric x chromosome in a case of refractory anaemia with ring sideroblasts associated with marked thrombocytosis.

Morales Camacho RM, Sanchez J, Marcos Luque I, Bernal R, Falantes JF, Pérez-Simón JA - Case Rep Genet (2014)

Bottom Line: Classical and molecular cytogenetic (FISH) studies of a bone marrow sample revealed the presence of isodicentric X chromosome [(idic(X)(q13)].Moreover, HUMARA assay showed the idic(X)(q13) as the active X chromosome.To our knowledge, this is the first reported case of an active isodicentric X in a woman with RARS-T.

View Article: PubMed Central - PubMed

Affiliation: Department of Haematology, Institute of Biomedicine of Seville (IBIS), University Hospital Virgen del Rocío, CSIC, University of Seville, 41013 Seville, Spain.

ABSTRACT
Refractory anaemia with ring sideroblasts and marked thrombocytosis (RARS-T) is a provisional entity in the World Health Organization (WHO) classification. It displays features characteristic of both myelodysplastic syndrome and myeloproliferative neoplasia plus ring sideroblasts ≥15% and marked thrombocytosis. Most patients with RARS-T show a normal karyotype. We report a 76-year-old woman diagnosed with RARS-T (76% of ring sideroblasts) with JAK2 (V617F) mutation and a load of 30-40%. Classical and molecular cytogenetic (FISH) studies of a bone marrow sample revealed the presence of isodicentric X chromosome [(idic(X)(q13)]. Moreover, HUMARA assay showed the idic(X)(q13) as the active X chromosome. This finding was correlated with the cytochemical finding of ring sideroblasts. To our knowledge, this is the first reported case of an active isodicentric X in a woman with RARS-T.

No MeSH data available.


Related in: MedlinePlus

HUMARA analysis. The panels show size-separation of PCR products by capillary electrophoresis. The x-axes show the sizes in base pairs and the y-axes the fluorescence activity. Each peak corresponds to one allele of the amplified microsatellite. Controls (a) and (b): random methylation pattern: no difference observed between the undigested sample (a) and digested sample (b). Patients (c) and (d). (c) Genomic DNA: two alleles are visible at 264 and 276 base pairs. Semiquantitative PCR showed that the 264-base pair allele was located on the idic(X)(q13), visible as a peak height ratio of 1.86. (d) After digestion, only the 276-base pair peak was present, showing that the isodicentric chromosome was active.
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fig2: HUMARA analysis. The panels show size-separation of PCR products by capillary electrophoresis. The x-axes show the sizes in base pairs and the y-axes the fluorescence activity. Each peak corresponds to one allele of the amplified microsatellite. Controls (a) and (b): random methylation pattern: no difference observed between the undigested sample (a) and digested sample (b). Patients (c) and (d). (c) Genomic DNA: two alleles are visible at 264 and 276 base pairs. Semiquantitative PCR showed that the 264-base pair allele was located on the idic(X)(q13), visible as a peak height ratio of 1.86. (d) After digestion, only the 276-base pair peak was present, showing that the isodicentric chromosome was active.

Mentions: The number of CAG tandem repeats allowed differentiating the allele corresponding to the idic(X)(q13) from the allele pertaining to the normal X chromosome. Initially, we performed a semiquantitative PCR analysis of the genomic DNA on a capillary electrophoresis system, obtaining a fluorescence signal for each allele on the locus for the HUMARA gene, shown as a peak and area under the curve. Since the amplified region was present in two copies on the isodicentric X chromosome, the assay showed a higher peak with a ratio close to 2 as compared to the height of the two separate alleles (Figure 2(c)). The XCI patterns revealed that the idic(X)(q13) belonged to the 100% active X chromosome (Figure 2(d)). The genomic DNA from a healthy volunteer served as a control to validate the experiment (Figures 2(a) and 2(b)).


An active isodicentric x chromosome in a case of refractory anaemia with ring sideroblasts associated with marked thrombocytosis.

Morales Camacho RM, Sanchez J, Marcos Luque I, Bernal R, Falantes JF, Pérez-Simón JA - Case Rep Genet (2014)

HUMARA analysis. The panels show size-separation of PCR products by capillary electrophoresis. The x-axes show the sizes in base pairs and the y-axes the fluorescence activity. Each peak corresponds to one allele of the amplified microsatellite. Controls (a) and (b): random methylation pattern: no difference observed between the undigested sample (a) and digested sample (b). Patients (c) and (d). (c) Genomic DNA: two alleles are visible at 264 and 276 base pairs. Semiquantitative PCR showed that the 264-base pair allele was located on the idic(X)(q13), visible as a peak height ratio of 1.86. (d) After digestion, only the 276-base pair peak was present, showing that the isodicentric chromosome was active.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3926399&req=5

fig2: HUMARA analysis. The panels show size-separation of PCR products by capillary electrophoresis. The x-axes show the sizes in base pairs and the y-axes the fluorescence activity. Each peak corresponds to one allele of the amplified microsatellite. Controls (a) and (b): random methylation pattern: no difference observed between the undigested sample (a) and digested sample (b). Patients (c) and (d). (c) Genomic DNA: two alleles are visible at 264 and 276 base pairs. Semiquantitative PCR showed that the 264-base pair allele was located on the idic(X)(q13), visible as a peak height ratio of 1.86. (d) After digestion, only the 276-base pair peak was present, showing that the isodicentric chromosome was active.
Mentions: The number of CAG tandem repeats allowed differentiating the allele corresponding to the idic(X)(q13) from the allele pertaining to the normal X chromosome. Initially, we performed a semiquantitative PCR analysis of the genomic DNA on a capillary electrophoresis system, obtaining a fluorescence signal for each allele on the locus for the HUMARA gene, shown as a peak and area under the curve. Since the amplified region was present in two copies on the isodicentric X chromosome, the assay showed a higher peak with a ratio close to 2 as compared to the height of the two separate alleles (Figure 2(c)). The XCI patterns revealed that the idic(X)(q13) belonged to the 100% active X chromosome (Figure 2(d)). The genomic DNA from a healthy volunteer served as a control to validate the experiment (Figures 2(a) and 2(b)).

Bottom Line: Classical and molecular cytogenetic (FISH) studies of a bone marrow sample revealed the presence of isodicentric X chromosome [(idic(X)(q13)].Moreover, HUMARA assay showed the idic(X)(q13) as the active X chromosome.To our knowledge, this is the first reported case of an active isodicentric X in a woman with RARS-T.

View Article: PubMed Central - PubMed

Affiliation: Department of Haematology, Institute of Biomedicine of Seville (IBIS), University Hospital Virgen del Rocío, CSIC, University of Seville, 41013 Seville, Spain.

ABSTRACT
Refractory anaemia with ring sideroblasts and marked thrombocytosis (RARS-T) is a provisional entity in the World Health Organization (WHO) classification. It displays features characteristic of both myelodysplastic syndrome and myeloproliferative neoplasia plus ring sideroblasts ≥15% and marked thrombocytosis. Most patients with RARS-T show a normal karyotype. We report a 76-year-old woman diagnosed with RARS-T (76% of ring sideroblasts) with JAK2 (V617F) mutation and a load of 30-40%. Classical and molecular cytogenetic (FISH) studies of a bone marrow sample revealed the presence of isodicentric X chromosome [(idic(X)(q13)]. Moreover, HUMARA assay showed the idic(X)(q13) as the active X chromosome. This finding was correlated with the cytochemical finding of ring sideroblasts. To our knowledge, this is the first reported case of an active isodicentric X in a woman with RARS-T.

No MeSH data available.


Related in: MedlinePlus