Prenatal origin of childhood AML occurs less frequently than in childhood ALL

Background While there is enough convincing evidence in childhood acute lymphoblastic leukemia (ALL), the data on the pre-natal origin in childhood acute myeloid leukemia (AML) are less comprehensive. Our study aimed to screen Guthrie cards (neonatal blood spots) of non-infant childhood AML and ALL patients for the presence of their respective leukemic markers. Methods We analysed Guthrie cards of 12 ALL patients aged 2–6 years using immunoglobulin (Ig) and T-cell receptor (TCR) gene rearrangements (n = 15) and/or intronic breakpoints of TEL/AML1 fusion gene (n = 3). In AML patients (n = 13, age 1–14 years) PML/RARalpha (n = 4), CBFbeta/MYH11 (n = 3), AML1/ETO (n = 2), MLL/AF6 (n = 1), MLL/AF9 (n = 1) and MLL/AF10 (n = 1) fusion genes and/or internal tandem duplication of FLT3 gene (FLT3/ITD) (n = 2) were used as clonotypic markers. Assay sensitivity determined using serial dilutions of patient DNA into the DNA of a healthy donor allowed us to detect the pre-leukemic clone in Guthrie card providing 1–3 positive cells were present in the neonatal blood spot. Results In 3 patients with ALL (25%) we reproducibly detected their leukemic markers (Ig/TCR n = 2; TEL/AML1 n = 1) in the Guthrie card. We did not find patient-specific molecular markers in any patient with AML. Conclusion In the largest cohort examined so far we used identical approach for the backtracking of non-infant childhood ALL and AML. Our data suggest that either the prenatal origin of AML is less frequent or the load of pre-leukemic cells is significantly lower at birth in AML compared to ALL cases

Both SEPT2 and MLL are down-regulated in MLL-SEPT2 therapy-related myeloid neoplasia

<p>Abstract</p> <p>Background</p> <p>A relevant role of septins in leukemogenesis has been uncovered by their involvement as fusion partners in <it>MLL</it>-related leukemia. Recently, we have established the <it>MLL-SEPT2 </it>gene fusion as the molecular abnormality subjacent to the translocation t(2;11)(q37;q23) in therapy-related acute myeloid leukemia. In this work we quantified <it>MLL </it>and <it>SEPT2 </it>gene expression in 58 acute myeloid leukemia patients selected to represent the major AML genetic subgroups, as well as in all three cases of <it>MLL-SEPT2</it>-associated myeloid neoplasms so far described in the literature.</p> <p>Methods</p> <p>Cytogenetics, fluorescence in situ hybridization (FISH) and molecular studies (RT-PCR, qRT-PCR and qMSP) were used to characterize 58 acute myeloid leukemia patients (AML) at diagnosis selected to represent the major AML genetic subgroups: <it>CBFB-MYH11 </it>(n = 13), <it>PML-RARA </it>(n = 12); <it>RUNX1-RUNX1T1 </it>(n = 12), normal karyotype (n = 11), and <it>MLL </it>gene fusions other than <it>MLL-SEPT2 </it>(n = 10). We also studied all three <it>MLL-SEPT2 </it>myeloid neoplasia cases reported in the literature, namely two AML patients and a t-MDS patient.</p> <p>Results</p> <p>When compared with normal controls, we found a 12.8-fold reduction of wild-type <it>SEPT2 </it>and <it>MLL-SEPT2 </it>combined expression in cases with the <it>MLL-SEPT2 </it>gene fusion (p = 0.007), which is accompanied by a 12.4-fold down-regulation of wild-type <it>MLL </it>and <it>MLL-SEPT2 </it>combined expression (p = 0.028). The down-regulation of <it>SEPT2 </it>in <it>MLL-SEPT2 </it>myeloid neoplasias was statistically significant when compared with all other leukemia genetic subgroups (including those with other <it>MLL </it>gene fusions). In addition, <it>MLL </it>expression was also down-regulated in the group of <it>MLL </it>fusions other than <it>MLL-SEPT2</it>, when compared with the normal control group (p = 0.023)</p> <p>Conclusion</p> <p>We found a significant down-regulation of both <it>SEPT2 </it>and <it>MLL </it>in <it>MLL-SEPT2 </it>myeloid neoplasias. In addition, we also found that <it>MLL </it>is under-expressed in AML patients with <it>MLL </it>fusions other than <it>MLL-SEPT2</it>.</p

SEPTIN12 Genetic Variants Confer Susceptibility to Teratozoospermia

It is estimated that 10–15% of couples are infertile and male factors account for about half of these cases. With the advent of intracytoplasmic sperm injection (ICSI), many infertile men have been able to father offspring. However, teratozoospermia still remains a big challenge to tackle. Septins belong to a family of cytoskeletal proteins with GTPase activity and are involved in various biological processes e.g. morphogenesis, compartmentalization, apoptosis and cytokinesis. SEPTIN12, identified by c-DNA microarray analysis of infertile men, is exclusively expressed in the post meiotic male germ cells. Septin12+/+/Septin12+/− chimeric mice have multiple reproductive defects including the presence of immature sperm in the semen, and sperm with bent neck (defect of the annulus) and nuclear DNA damage. These facts make SEPTIN12 a potential sterile gene in humans. In this study, we sequenced the entire coding region of SEPTIN12 in infertile men (n = 160) and fertile controls (n = 200) and identified ten variants. Among them is the c.474 G>A variant within exon 5 that encodes part of the GTP binding domain. The variant creates a novel splice donor site that causes skipping of a portion of exon 5, resulting in a truncated protein lacking the C-terminal half of SEPTIN12. Most individuals homozygous for the c.474 A allele had teratozoospermia (abnormal sperm <14%) and their sperm showed bent tail and de-condensed nucleus with significant DNA damage. Ex vivo experiment showed truncated SEPT12 inhibits filament formation in a dose-dependent manner. This study provides the first causal link between SEPTIN12 genetic variant and male infertility with distinctive sperm pathology. Our finding also suggests vital roles of SEPT12 in sperm nuclear integrity and tail development

t(11;22)(q23;q11.2) In acute myeloid leukemia of infant twins fuses MLL with hCDCrel, a cell division cycle gene in the genomic region of deletion in DiGeorge and velocardiofacial syndromes

We examined the MLL genomic translocation breakpoint in acute myeloid leukemia of infant twins. Southern blot analysis in both cases showed two identical MLL gene rearrangements indicating chromosomal translocation. The rearrangements were detectable in the second twin before signs of clinical disease and the intensity relative to the normal fragment indicated that the translocation was not constitutional. Fluorescence in situ hybridization with an MLL-specific probe and karyotype analyses suggested t(11;22)(q23;q11. 2) disrupting MLL. Known 5\u27 sequence from MLL but unknown 3\u27 sequence from chromosome band 22q11.2 formed the breakpoint junction on the der(11) chromosome. We used panhandle variant PCR to clone the translocation breakpoint. By ligating a single-stranded oligonucleotide that was homologous to known 5\u27 MLL genomic sequence to the 5\u27 ends of BamHI-digested DNA through a bridging oligonucleotide, we formed the stem-loop template for panhandle variant PCR which yielded products of 3.9 kb. The MLL genomic breakpoint was in intron 7. The sequence of the partner DNA from band 22q11.2 was identical to the hCDCrel (human cell division cycle related) gene that maps to the region commonly deleted in DiGeorge and velocardiofacial syndromes. Both MLL and hCDCrel contained homologous CT, TTTGTG, and GAA sequences within a few base pairs of their respective breakpoints, which may have been important in uniting these two genes by translocation. Reverse transcriptase-PCR amplified an in-frame fusion of MLL exon 7 to hCDCrel exon 3, indicating that an MLL-hCDCrel chimeric mRNA had been transcribed. Panhandle variant PCR is a powerful strategy for cloning translocation breakpoints where the partner gene is undetermined. This application of the method identified a region of chromosome band 22q11.2 involved in both leukemia and a constitutional disorder