Monitoring the isochromosome i(7)(q10) in the bone marrow of patients with Shwachman syndrome by real-time quantitative PCR.
Clonal chromosome anomalies may be found in the bone marrow (BM) of patients with Shwachman syndrome, who are at risk to develop myelodysplastic syndromes and/or acute myeloid leukemias. In particular, an isochromosome i(7)(q10) is frequent, and is usually monitored by chromosome analyses. We tested an approach by real-time quantitative polymerase chain reaction (RQ-PCR) on a chromosome 7 polymorphism. Five DNA samples of 2 Shwachman syndrome patients with clonal i(7)(q10) in the BM were used. Both were heterozygous for the diallelic indel polymorphism MID1064, which maps in 7q35. The percentage of i(7)(q10)-positive cells was extrapolated from the ratio of the 2 alleles measured by means of an allele-specific RQ-PCR assay. The results were compared with cytogenetic analyses on the same material used for RQ-PCR. In 1 patient, the RQ-PCR results matched well with those of chromosome analyses, whereas in the other one RQ-PCR showed that around 40% of the BM cells were abnormal, while they resulted to be nearly 80% with conventional monitoring assays. As the results obtained by RQ-PCR refer to the DNA of around 128,000 BM cells, our method proved to be feasible and more efficient in the quantitative evaluation of the i(7)(q10)-positive clone than conventional ones.
Porta
Giovanni
G
Dipartimento di Scienze Biomediche Sperimentali e Cliniche, Università dell'Insubria, Varese, Italy.
Mattarucchi
Elia
E
Maserati
Emanuela
E
Pressato
Barbara
B
Valli
Roberto
R
Morerio
Cristina
C
Zecca
Marco
M
Panarello
Claudio
C
Locatelli
Franco
F
Lo Curto
Francesco
F
Pasquali
Francesco
F
D000015:Abnormalities, Multiple / Q000235:genetics* / Q000473:pathology; D000328:Adult; D001855:Bone Marrow Diseases / Q000235:genetics* / Q000473:pathology; D002648:Child; D002897:Chromosomes, Human, Pair 7 / Q000235:genetics*; D020732:Cytogenetic Analysis / Q000379:methods; D005260:Female; D005808:Genes, Recessive; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods; D018404:Isochromosomes / Q000235:genetics*; D008297:Male; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D013577:Syndrome