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Biomedical subjects

M G Mattei

Publications and source records attributed to M G Mattei.

At least 379 records · Page 21Linked to original sources
PubMed1982

X-autosome translocations: cytogenetic characteristics and their consequences.

To define the principal characteristics of X-autosome translocations, the authors present a study of 105 cases, five of which are personal observations. The autosomal pairs 15, 21, and 22 are affected by t(X-Aut) more often than would be expected. The distribution of breakpoints on the X chromosome does not differ significantly from the expected distribution. The analysis of different patterns of inactivation seems to confirm that the inactivation could occur at random, but would be followed by a cellular selection favoring the better genetic balance. An estimate of the incidence of t(X-Aut) is proposed, based upon the conclusions that only one chromosome is susceptible to translocation in meiosis in both males and females and that all affected men will be sterile, as will be 50% of women.

Chromosome Banding↗
PubMed1981

X-linked mental retardation with the fragile X. A study of 15 families.

The clinical and cytogenetic features of 15 families with mental retardation linked to the fragile site on the X chromosome are presented. The 15 propositi were all prepubertal, and one was a girl. Although the clinical picture varied in severity, it was sufficiently constant to suggest the diagnosis from the facial features and the encephalopathy with language retardation and disturbed behavior. Macroorchidism was not seen before puberty. The fragile X chromosome was found in seven of the nine mothers studied and in two mildly retarded sisters and has also been demonstrated in fibroblasts in eleven subjects with the abnormality.

Adolescent↗
PubMed1981

Partial inversion of the secondary constriction of chromosome 9. Does it exist?

Pericentric inversion of chromosome 9, a common abnormality, has been much studied because of its possible genetic effect. Apart from total inversion, in which the whole heterochromatic segment of chromosome 9 appears to be situated on the short arm, some authors describe partial inversion, in which the heterochromatin is found partly on the long arm and partly on the short arm. Our study indicates that firstly, the heterochromatic segment of chromosome 9 is composed of two biochemically different subunits: the heterochromatin of the centromere itself and the heterochromatin of the secondary constriction. Secondly, it suggests that partial inversion of the secondary constriction of chromosome 9 is an unusual event, as the majority of published cases can be interpreted as the result of an increase in the centromeric heterochromatin without alteration of the secondary constriction.

Centromere↗
PubMed1981

[Individual variability of associations between acrocentrics (author's transl)].

We studied the quantitative and qualitative variation of associations between acrocentric chromosomes in four subjects on a period of ten months; results show a definite tendency of association in a same subject, tendency which is reproducible and clear. Even though each individual has a determined rate of associations, the number of associated chromosomes and the number of associations themselves do not vary with months. Furthermore, associations do not appear at random; indeed, they have a wide spectrum of variations from one subject to the other but if we take the subjects individually, their associative rate concerning each chromosome do not change with months. Therefore, the phenomenon of association could be viewed as a biological characteristic of each individual.

Adult↗
PubMed1980

Maternal age and origin of non-disjunction in trisomy 21.

The role of maternal age in chromosomal non-disjunction was investigated by studying 51 families in whom the origin of the meiotic anomaly had been identified. Results of this study were compared with previously published data. This comparison did not show any difference in mean maternal age, nor in distribution of maternal ages when the origin of non-disjunction was maternal, or paternal, or occurred at the first or second meiotic division. These results make questionable the role of maternal age in the birth of Down's syndrome children.

Chromosome Banding↗
PubMed1980

[Chromosome abnormalities: known risk factors].

The high incidence of chromosomal anomalies at birth and the severity of the resulting handicap led to examining their detectability by amniocentesis. With current indications for amniocentesis, the detection rate did not excede 30%. Consequently, it seems necessary to estimate the importance of other known risk factors and to calculate the resulting impact this would have on eventually broadening the indications for amniocentesis. A review of the literature led the authors to discuss the relative importance of each known risk factor and its role in public health.

Amniocentesis↗
PubMed1979

Abnormal childhood phenotypes associated with the same balanced chromosome rearrangements as in the parents.

Three patients have been detected because of abnormal phenotypes. Balanced chromosome rearrangements were found in their karyotypes, and in one of the parents in each case. In these three families the association of an abnormal phenotype and a balanced chromosome rearrangement may either be a chance happening or be induced by a submicroscopic loss of chromosome material, for which different position effects may be responsible, according to the case in question. These observations prompt us to ask what decision should be made relative to termination of pregnancy if such a rearrangement is found in amniotic cells in a family with a previous abnormal child.

Adult↗
PubMed1979

Origin of the extra chromosome in trisomy 21.

Of 61 families of children with trisomy 21, polymorphism of chromosome 21 elucidating the origin of the extra chromosome was found in 42. Nondisjunction was of paternal origin in 8 cases (19.04%) and the anomaly occurred with equal frequency during the first and second meiotic divisions. Maternal nondisjunction was demonstrated in 34 cases (80.95%), in which nondisjunction occurred by far the most often during the first meiotic division (29 cases). These results are in agreement with data from the literature, and suggest the existence of at least two different causes for chromosomal nondisjunction, the first being the same in both sexes and occurring in both meiotic divisions and the second specifically limited to the first meiotic division in the mother.

Chromosome Banding↗