Constitutive heterochromatin polymorphisms in children with acute lymphoblastic leukemia

Is there a possible correlation between chromosomal variants and spermatogenesis?

AIM

Heterochromatin polymorphism is considered a variant of a normal karyotype but is more frequent in infertile men. The aim of this study was to evaluate the correlation between heterochromatic variants and male infertility and to discuss the possible mechanisms of how heterochromatic polymorphism might affect spermatogenesis.

METHODS

Cytogenetic analysis was undertaken in 210 infertile males who had been taken into assisted reproductive techniques and in 183 men with proven fertility. Additionally, C-banding was performed in men with heterochromatin polymorphism. Sperm fluorescence in situ hybridization (FISH) was applied in 54 men with normal karyotype presenting either normal or abnormal sperm parameters as well as in 8 men with heterochromatin polymorphism. The outcomes of assisted reproductive techniques were compared between infertile men with normal karyotype and men with heterochromatin polymorphism.

RESULTS

The incidence of heterochromatin polymorphism was higher in infertile men. The most frequent chromosome involved in heterochromatin polymorphism was chromosome 9. Sperm FISH analysis revealed an increased rate of aneuploidy in men with heterochromatin polymorphism. Laboratory and clinical outcomes in assisted reproductive techniques were compromised in men with heterochromatin polymorphism.

CONCLUSIONS

An increased rate of heterochromatin polymorphism in infertile males seems to be more than an incidental finding, and must not be considered as a normal variant. Polymorphic heterochromatin may have deleterious effects on the genetic constitution of spermatozoa. More attention must be directed to infertile men with heterochromatin polymorphism.

Cytogenetic studies in children with Down syndrome and acute leukemia

The frequency of chromosomal alterations was compared among four children groups: those with Down syndrome and acute leukemia (DS/AL), those with acute leukemia (AL), those with only Down syndrome (DS) and healthy children (NC). The frequency of acquired chromosome abnormalities was larger in the AL group, followed by the DS/AL. The gaps and isogaps were more frequent in children with only DS. The polymorphisms of the constitutive heterochromatin were larger in the DS/AL group. These findings appear to imply that more genetic changes are necessary to develop AL in the case of healthy children compared to children with DS.

Familial Myelodysplastic Syndrome/Acute Myeloid Leukaemia With Monosomy 7: Report of a New Kindred

Familial juvenile myeloid disorders are uncommon, but better understanding of their basis may lead to crucial advances in the study of leukemogenesis. We report a family with three siblings who died of myelodysplasia and/or acute myeloid leukemia at the age of 10, 11 and 16 years, respectively. Two children died of a fulminant generalized varicella. No somatic constitutional abnormalities were found and histories of exposure to common environmental or occupational mutagens were unremarkable. One of the two tested patients had monosomy of the chromosome 7 in all examined metaphases. Therefore, the clinical and genetic findings are consistent with the "Familial Monosomy 7". A constitutional pericentric inversion of chromosome 9 (p11q13) was detected in the karyotype of the father and both analyzed siblings. In addition, clustering of breast cancer was observed in maternal relatives. As the mode of inheritance and the molecular basis of this disease remain obscure, we believe that it is important to report new cases and attempt to study them as thoroughly as possible. We discuss possible mechanisms of familial tendency to myeloid malignancies.