Micronucleated lymphocytes in parents of Down syndrome children

Down syndrome (DS) is the most common disease due to an autosomal aneuploidy in live born children and also the major known genetic cause of mental retardation. The risk of a DS pregnancy increases substantially with increasing maternal age. However, several women aged less than 35 years at conception have a child with DS. The micronucleus (MN) assay can identify chromosome breakage or chromosome malsegregation and is an ideal biomarker to investigate genomic instability. The aim of the present study was to determine the frequency of peripheral lymphocytes with MN in the parents of DS individuals. The subjects were 17 couples, 1 father and 9 mothers, and 24 couples who had at least one healthy child formed the control group. For each individual we evaluated the frequency of binucleated micronucleated lymphocytes (BNMN%) as number of binucleated lymphocytes containing one or more MN per 1000 binucleated cells. The mean age of DS parents and controls was 32.6 and 29.8 years, respectively. The frequency of MN in DS parents was significantly higher compared to controls. The higher frequency of MN in DS parents suggests a higher predisposition of DS parents to aneuploidy events in this sample.

Micronucleated lymphocytes in parents of Down syndrome children.

Down syndrome (DS) is the most common disease due to an autosomal aneuploidy in live born children and also the major known genetic cause of mental retardation. The risk of a DS pregnancy increases substantially with increasing maternal age. However, several women aged less than 35 years at conception have a child with DS. The micronucleus (MN) assay can identify chromosome breakage or chromosome malsegregation and is an ideal biomarker to investigate genomic instability. The aim of the present study was to determine the frequency of peripheral lymphocytes with MN in the parents of DS individuals. The subjects were 17 couples, 1 father and 9 mothers, and 24 couples who had at least one healthy child formed the control group. For each individual we evaluated the frequency of binucleated micronucleated lymphocytes (BNMN%) as number of binucleated lymphocytes containing one or more MN per 1000 binucleated cells. The mean age of DS parents and controls was 32.6 and 29.8 years, respectively. The frequency of MN in DS parents was significantly higher compared to controls. The higher frequency of MN in DS parents suggests a higher predisposition of DS parents to aneuploidy events in this sample.

A dup(17)(p11.2p11.2) detected by fluorescence in situ hybridization in a boy with Alport syndrome.

We describe a de novo dup 17p11 in a boy with Alport syndrome, mild mental retardation, and minor anomalies. Combining classical and molecular cytogenetics analyses, the karyotype was defined as 46,XY.ish dup (17)(p11.2p11.2)(D17S29++,D17S379+). Alport syndrome is associated with mutations in the type IV alpha chain collagen gene, however, no known collagen-related gene is currently mapped to 17p11. Duplications involving 17p11.2 have been reported in Charcot-Marie-Tooth disease, Dejerine-Sottas syndrome, and in a few sporadic patients with mental retardation and minor anomalies, however, no significant clinical similarity was found among these cases and the propositus. Further studies may clarify the meaning of the association between Alport syndrome and duplications of DNA sequences mapped at 17p11.2.

Human chromosome aberrations induced in vitro by Paracoccidioides brasiliensis glycoproteic component (GP 43).

The in vitro cytogenetic effects of the 43-kDa molecular mass exocellular glycoproteic component (GP 43) from Paracoccidioides brasiliensis were studied in cultures from human lymphocytes. The sample included 10 healthy, white, non-smoking, non-related males (mean age of 31.3 +/- 8.2 years). Besides the control, three concentrations of GP 43 (0.125, 1.25 and 5 micrograms/ml) were used. In each group, around 1000 cells were examined in search of chromosome aberrations, and 30000 metaphases were analysed for the determination of the Mitotic Index. The authors conclude that GP 43 most probably causes inhibition of the cell cycle and aneugenic and clastogenic effects.

Cycloactive, aneugenic and clastogenic effects of Paracoccidioides brasiliensis exoantigen in human lymphocyte cultures.

The in vitro effect of Paracoccidioides brasiliensis exoantigen on the human lymphocytes cell cycle and chromosomes was studied. Human peripheral blood lymphocyte cultures from ten healthy, white, non-smoking, non-related adult males (mean age 31.3 +/- 8.2 years) were studied. Blood cultures were treated with three exoantigen concentrations (0.25, 2.50 and 10.00 micrograms ml-1). At least 1000 metaphases were analysed at each concentration, for evaluation of numerical and structural chromosome aberrations (CA) and 30,000 for mitotic index (MI). Among the treated cultures, statistically significant differences in the frequencies of MI and CA were not observed. Nevertheless, when compared with control cultures, they all showed a significantly lower frequency of MI and higher frequency of CA. It is suggested that the detected alterations were caused by the exoantigen, its fractions or its metabolites.

[The association between glyoxalase I and paracoccidioidomycosis infection]. / Associação entre glioxalase I e paracoccidioidomicose-infecção.

With the purpose to study the genetic susceptibility to paracoccidioidomycosis infection we searched for a possible association between glyoxalase I and the intradermic paracoccidioidin reaction. The phenotype GLO 1 was significantly more frequent among positive reactors.

Cholesteryl ester storage disease. Report of a case.

Cholesteryl ester storage disease (CESD) is a rare disorder of familial incidence characterized by the accumulation of cholesteryl ester and triglycerides in the liver, intestine and bone marrow. Until now only 21 cases have been reported in the literature. We present a 9 months old girl presenting with increased abdominal girth. She had normal liver function tests and increased cholesterol and triglycerides serum levels. The liver biopsy showed many cholesterol cristals seen as needle shaped cristals under polarized light. This is the youngest patient being diagnosed clinically in the literature.