5q-Syndrome in a patient with chronic exposure to ionizing radiation

Microglia-specific knock-out of NF-κB/IKK2 increases the accumulation of misfolded α-synuclein through the inhibition of p62/sequestosome-1-dependent autophagy in the rotenone model of Parkinson's disease

Parkinson's disease (PD) is the most common neurodegenerative movement disorder worldwide, with a greater prevalence in men than women. The etiology of PD is largely unknown, although environmental exposures and neuroinflammation are linked to protein misfolding and disease progression. Activated microglia are known to promote neuroinflammation in PD, but how environmental agents interact with specific innate immune signaling pathways in microglia to stimulate conversion to a neurotoxic phenotype is not well understood. To determine how nuclear factor kappa B (NF-κB) signaling dynamics in microglia modulate neuroinflammation and dopaminergic neurodegeneration, we generated mice deficient in NF-κB activation in microglia (CX3CR1-Cre::IKK2fl/fl ) and exposed them to 2.5 mg/kg/day of rotenone for 14 days, followed by a 14-day post-lesioning incubation period. We postulated that inhibition of NF-κB signaling in microglia would reduce overall inflammatory injury in lesioned mice. Subsequent analysis indicated decreased expression of the NF-κB-regulated autophagy gene, sequestosome 1 (p62), in microglia, which is required for targeting ubiquitinated α-synuclein (α-syn) for lysosomal degradation. Knock-out animals had increased accumulation of misfolded α-syn within microglia, despite an overall reduction in neurodegeneration. Interestingly, this occurred more prominently in males. These data suggest that microglia play key biological roles in the degradation and clearance of misfolded α-syn and this process works in concert with the innate immune response associated with neuroinflammation. Importantly, the accumulation of misfolded α-syn protein aggregates alone did not increase neurodegeneration following exposure to rotenone but required the NF-κB-dependent inflammatory response in microglia.

5q(-)survival: importance of gender and deleted 5q bands and survival analysis based on 324 published cases

Survival of 5q(-)patients is known to depend on patient age, diagnosis, and acquisition of additional chromosome aberrations. The possible importance of the deleted 5q bands is unknown; nor is it known if the same or different factors are of prognostic importance in 5q(-)MDS and 5q(-)AML. In order to obtain material of sufficient size to answer these and other questions the literature was searched for 5q(-)cases with data on survival. Only MDS and AML cases with interstitial deletions were included. The results confirmed the prognostic importance of the factors mentioned above, but produced the following new data: In MDS, but not in AML, loss of the band 5q12 is an independent adverse prognostic factor; female patients survive longer in MDS while in AML men are the longer survivors; del(5)(q13q31) was found to be associated with MDS, 5q(-)as the sole aberration, and a long survival; on the other hand many del(5)(q12q32) cases showed AML, presence of additional aberrations, and short survivals. On the basis of these results the following hypotheses are proposed: 1) the female preponderance in 5q(-)MDS is due to longer female survival, and not to increased female incidence, and 2) some 5q deletions have a high diagnostic specificity, affect the rate of development of additional chromosome aberrations and thus in fact are major prognostic factors.

Clonal evolution in primary 5q-syndrome

Primary 5q-syndrome is a type of myelodysplastic syndrome characterized by refractory anemia, thrombocytosis, and hypolobulated megakaryocytes. The risk of leukemic transformation is low. A case of 5q- syndrome that occurred in a 42-year-old woman and was complicated by leukemic transformation 7 years after the initial diagnosis is reported. An additional clonal karyotypic anomaly, del(7q), was seen in the leukemic cells. The literature on leukemic and karyotypic evolution of primary 5q- syndrome is reviewed and the implication of karyotypic evolution is discussed.

5q- syndrome terminating in acute myeloid leukemia. Karyotype evolution and immunologic characterization of blast cells

We report a case of 5q- syndrome that progressed to acute nonlymphocytic leukemia after 9 years of clinically and morphologically stable disease. The transition from the chronic to the leukemic phase was characterized by the appearance of an additional cytogenetic anomaly [inv(2)] in the cell carrying the 5q-, together with the expansion of a clone showing an apparently normal karyotype.

Cytogenetic study of a Merkel cell carcinoma

Banded karyotypes from two metastatic sites of a Merkel cell carcinoma were analyzed. The results indicate very close similarity between the two specimens including an overall tendency to triploidy and the same five marker chromosomes. One of the markers represented by two copies in most of the karyotyped cells was 1q-.

The 5q-anomaly

A deletion of the long arm of chromosome #5 (5q-) occurs nonrandomly in human malignancies. As a rule, the deletion is interstitial; the distal breakpoint by conventional techniques is usually in band q32, the proximal breakpoints in q12 or q14. Variant breakpoints occur in less than 10% of all cases. As the sole anomaly, 5q- is characteristically found in refractory anemia with or without excess of blasts. It can occur as the sole anomaly in de novo or secondary acute nonlymphocytic leukemia, but is usually accompanied in those disorders by other chromosome changes that are also nonrandomly distributed. In addition, it can be found in lymphoproliferative disorders, and occasionally, also in solid tumors. The 5q- myelodysplastic syndrome typically occurs in older age groups, particularly in females. Characteristic features are macrocytic anemia, normal or elevated platelets in the presence of megakaryocytic anomalies, and a mild clinical course. In cases with 5q- only, transformation into ANLL occurs rarely. Additional chromosome anomalies and male sex are prognostically unfavorable signs. Sex ratio is also at the disadvantage of females in de novo 5q- ANLL, and the latter disorder can occur without being preceded by a myelodysplastic phase. A myelodysplastic phase usually precedes 5q- secondary leukemia, in males as well as in females, and additional chromosome anomalies, especially of chromosome #7, are almost invariably present in those cases. We conclude that 5q- is the most frequently occurring single chromosome anomaly in secondary leukemia. Furthermore, the resemblance between de novo and secondary 5q- MDS and ANLL is striking; clinically, as well as cytogenetically, they are indistinguishable, suggesting that all de novo cases may be due to environmental (chemical) carcinogens. Response to treatment and prognosis are very poor with current therapeutic regimens in de novo as well as in secondary 5q- ANLL. Morphologically, these ANLLs fall into all FAB categories. There is considerable evidence to show that the 5q- anomaly occurs in a myeloid precursor stem cell. The occasional occurrence in lymphoid malignancies, of B cell as well as T cell type, suggests that, as in Ph-positive disorders, a common progenitor stem cell may be affected in 5q- also. The 5q- lymphoid malignancies, however, are much more rare; it is not clear at the present time whether or not a 5q- counterpart of Ph-positive ALL exists, and mixed lymphoid-myeloid 5q- disorders have not yet been documented.(ABSTRACT TRUNCATED AT 400 WORDS)

Acquired partial deletions of the long arm of chromosome 5 in hematologic disorders

We have analyzed the data on 105 patients reported with a deletion of part of the long arm of chromosome 5 in the presence of hematologic disease. The major conditions associated with this abnormality are refractory anemia, polycythemia vera, and acute myelogenous leukemia, as well as the occasional occurrence of several other problems.

The 5q--syndrome: an underdiagnosed form of macrocytic anaemia

Since the description in 1974 of the 5q--syndrome, only 29 cases have been reported. Over a 3 1/2 year period cytogenetic culture of bone marrow submitted from 344 patients being investigated for a blood disorder revealed nine patients with anomalies of chromosome 5. In five of these patients (samples arising from 37 patients being investigated for refractory macrocytic or aplastic anaemia) the 5q-syndrome was diagnosed. The clinical and haematological findings of this syndrome are reviewed and attention is drawn to the importance of reviewing megakaryocytic numbers and morphology in refractory macrocytic anaemia if the diagnosis is to be considered. The diagnosis is compatible with prolonged survival and establishing it prevents repeated and unnecessary investigation.