[Chromosomal pathology. Recent advances].
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Chromosome Aberrations↗
Biomedical subjects
J F Mattei
Publications and source records attributed to J F Mattei.
[Small supernumerary chromosomes].
We report 23 cases of small supernumerary chromosome examined at the Medical Genetics Center of Marseille. Genetic counselling is depending on the origin of the additional chromosomal material. Among the different cytogenetic technics which are useful in such an identification in situ hybridisation is a new technic very helpful in some cases, especially iso p18.
Chromosome Aberrations↗
[Cohen's syndrome in 2 sisters].
A new familial observation of Cohen syndrome in two sisters is reported. Both children exhibited the typical features of Cohen syndrome, i.e. obesity, hypotonia, mental deficiency and a dysmorphic syndrome mainly involving the facies and extremities. More accurate delineation of the nosologic limits of this syndrome is ensured by a critical review of the 17 observations published in the medical literature, which include 9 familial cases: the contribution of subsequent observations to the initial description is pointed out. Attention is drawn to the unusual course of the obesity which typically occurs after five years of age, in contrast to common obesities. Furthermore, Cohen syndrome is remarkable by the morphologic abnormalities, particularly those of the facies, which should suggest the diagnosis. As in our observation, data from the literature is in support of autosomic recessive inheritance which implies restrictive genetic counseling.
Abnormalities, Multiple↗
Chromosome 15 anomalies and the Prader-Willi syndrome: cytogenetic analysis.
The behaviour of chromosome 15 is very different from that of the other acrocentric chromosomes. The cytogenetic characteristics of rearrangements associated with Prader-Willi syndrome (PWS) are analyzed as similar rearrangements irrespective of the associated phenotype (reciprocal translocations of chromosome 15, small bisatellited additional chromosomes, Robertsonian translocations, interstitial deletions, pericentric inversions). This study suggests that: (1) The proximal ( 15q ) region and PWS seem to be indissociable ; (2) chromosome 15 has an indisputable cytogenetic originality which could be related to its histochemical properties. Chromosome 15 constitutive heterochromatin usually contains much 5-methylcytosine-rich DNA and a large amount of each of the four satellite DNAs. Furthermore the existence in the proximal ( 15q ) region of one or several palindromic sequences could be postulated to explain the great lability of this region of chromosome 15.
Chromosome Aberrations↗
Three new cases of partial monosomy 21 resulting from one ring 21 chromosome and two unbalanced reciprocal translocations.
Three patients with partial monosomy of the long arm of chromosome 21 are reported. Each one presents several features of a 21q--syndrome but in cases 2 and 3, other chromosomes are involved, contributing to the variability of the clinical picture. Synthesis of clinical, enzymatic and cytogenetic findings confirms that the superoxide dismutase A (SOD-A) locus is in sub-band 21q22-1. However, it is not possible to localize precisely the segments responsible for the different clinical features of 21q--syndrome.
Adult↗
Wilms' tumor, malformative syndrome, mental retardation and de novo constitutional translocation, t(7;13)(q36;q13).
An apparently balanced de novo constitutional translocation (7;13) (q36;q13) was detected on peripheral lymphocytes and fibroblasts of a 14-month-old boy. The patient presented a facial dysmorphism with hydrocephaly and mental retardation associated with a Wilms' tumor. A pure coincidence of random association cannot be ruled out but one can equally assert the plausibility of a minimal unnoticed deletion or a position effect.
Abnormalities, Multiple↗
Bilateral retinoblastoma with de novo constitutional balanced translocation t(2;9)(q11;p11).
The case of a 6-year-old boy with bilateral retinoblastoma (RB) and apparently de novo balanced translocation t(2;9)(q11;p11) is presented. The normality of 13q14 chromosome region has been confirmed using high resolution techniques and Esterase D assay. The hypothesis that this RB might be correlated to the translocation is discussed.
Child↗
Cluster of acute infantile spinal muscular atrophy (Werdnig-Hoffmann disease) in a limited area of Reunion Island.
A retrospective study of Werdnig-Hoffmann disease (spinal muscular atrophy type I) was undertaken on Reunion Island. Nineteen WH cases born between 1969 and 1980 were recorded belonging to thirteen sibships of the European population of the island. Genealogical analysis, going back to the XVIIth century (1642), showed a relationship among the 13 families, which were derived from a common ancestral pair. A founder effect is the most probable explanation for the concentration of Werdnig-Hoffmann disease in the area.
Adolescent↗
Immunoreactive copper-zinc superoxide-dismutase (SOD-1) in mosaic trisomy 21 and normal subjects.
Copper-zinc superoxide-dismutase (SOD-1) (E.C. 1.15.11) levels were measured in 9 children with mosaic trisomy 21 as identified by R, H, G-banding technics. Radioimmunoassay of erythrocytes and fibroblasts did not demonstrate any significant correlation between levels of SOD-1 and percentage of trisomic 21 cells in the two target cell populations studied.
Down Syndrome↗
HLA and trisomy 21. Confirmation of a trend of restricted HLA heterogeneity in parents of Down syndrome children.
As the HLA system could play a role in the in utero selection process against abnormal fetuses, HLA-A and -B antigens were evidenced in 30 children with trisomy 21 and in their parents, using a standard microlymphocytotoxicity test. The comparison group included 60 families among whom 39 had HLA typing for paternity exclusion and 21 had been previously selected for a segregation study. Both groups consisted of nonconsanguineous Caucasians from the same geographical area. The Down syndrome (DS) children did not show a significant association with a specific HLA antigen. However, six out of 30 couples having a DS child showed two antigens shared at the A and/or B locus, compared to seven out of 60 control couples. The shared parental antigens were not selectively inherited, and the proportion of homozygote children at one locus was lower for DS (5/30) than for controls (13/60). These findings demonstrate the same trend as previously published but need to be confirmed by other investigators. Perhaps a strong selective pressure in favor of heterozygotes contributes to a better survival rate, as suggested from histocompatibility studies in animals.
Adult↗
[Mental retardation linked to fragility of chromosome X: current knowledge].
The association of the fragile X chromosome with X-linked mental retardation is now well established. The main clinical features are mental retardation, typical facial dysmorphism and macroorchidism. Cytogenetically there is a fragile site in band Xq27-28 which can be demonstrated using specific techniques. The genetic studies are compatible with a X-linked dominant inheritance with an incomplete penetrance. A preliminary estimation of an overall frequency of 1: 2000 males for the fra(X)(q) condition is suggested.
Bromodeoxyuridine↗
Immunoreactive Cu-SOD and Mn-SOD in lymphocytes sub-populations from normal and trisomy 21 subjects according to age.
Copper and manganese superoxide dismutases (Cu-SOD and Mn-SOD) were measured by radioimmunoassay in B and T lymphocytes and macrophages, in patients with trisomy 21 and in matched controls. In the controls, Cu-SOD was present in greater amounts than Mn-SOD and there were quantitative differences in the distribution in the three cellular sub-populations. In trisomy 21, levels of Cu-SOD were raised, with no change in levels of Mn-SOD, supporting the theory of a gene dosage effect. There were significant positive and negative correlations between age and Cu-SOD levels in controls, and a correlation approaching significance for Mn-SOD. In trisomy 21, there was no correlation between age and Cu-SOD levels, and the only significant correlation for Mn-SOD was for B lymphocytes.
Adolescent↗
Brief clinical report: HARD (+/- E) syndrome: report of a sixth family with support for autosomal-recessive inheritance.
We report on two sibs with hydrocephalus, encephalocele, agyria and ocular anomalies, an association known as the HARD +/- E syndrome. This is thought to be the sixth reported family and third instance of familial occurrence of this autosomal-recessive syndrome which deserves consideration in the nosology of every case of neural tube defect (hydrocephalus).
Abnormalities, Multiple↗
Franceschetti syndrome in a child with a de novo balanced translocation (5;13)(q11;p11) and significant decrease of hexosaminidase B.
We report a previously undescribed case of a de novo balanced translocation t(5;13)(q11;p11) and Franceschetti syndrome in a 3-year-old girl. The hypothesis that this unusual association might not be coincidental but rather due to position effect is proposed. Moreover the significant decrease of hexosaminidase B activity suggests the localization of this gene on the 5q11 band.
Acetylglucosaminidase↗
Prader-Willi syndrome and chromosome 15. A clinical discussion of 20 cases.
A chromosome 15 anomaly was observed in 12 of 20 patients, 17 of whom were clinically suspected of having Prader-Willi syndrome (PWS). The clinical features of eight cases with 15q11-12 deletion were very similar to those originally described in PWS. On the other hand, the group of normal karyotype patients is heterogeneous, and their features do not strictly correspond to the clinical definition of PWS. However, the hypothesis that PWS is associated with deletion of 15q11-12 can neither explain the apparently balanced translocations of chromosome 15 nor account for the small supernumerary metacentric chromosomes corresponding to an isochromosome 15 for band 15q11 observed in some cases.
Adolescent↗
X-linked mental retardation, growth retardation, deafness and microgenitalism. A second familial report.
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Deafness↗
Genetic aspects of artificial insemination by donor (AID). Indications, surveillance and results.
The results provided by the Fédération des Centres d'Etude et de Conservation du Sperme Humain (CECOS) are based on 15,283 requests for AID. They are analysed from the point of view of medical genetics. The genetic indications represent 0.77% of requests for AID and can be separated into four groups: dominant autosomal abnormalities in the man, previous children affected by autosomal recessive conditions, chromosomal abnormalities in the man, and a miscellaneous group. In 2,502 births, a total of 45 malformations was seen, including nine chromosomal abnormalities. The possibility of an early amniocentesis for prenatal diagnosis in every pregnancy after AID is discussed.
Chromosome Aberrations↗
Syndrome of polydactyly, cleft lip, lingual hamartomas, renal hypoplasia, hearing loss, and psychomotor retardation: variant of the Mohr syndrome or a new syndrome?
Three sibs, the proband and two monozygotic twins, have a condition including mental retardation, postnatal somatic retardation, preaxial polydactyly of the feet, bifid third metacarpal, median cleft lip, fatty hamartomas on the dorsum of the tongue, conductive hearing loss, and unilateral or bilateral renal agenesis. This probably autosomal recessive syndrome could be a further example of the condition described by Váradi et al or a variant of the Mohr syndrome.
Abnormalities, Multiple↗