An ovarian dysgerminoma in Down syndrome. Hypothesis about the association.

An 11-year-old girl with Down syndrome (DS) was operated for a stage I right ovary dysgerminoma. She is in good health 33 years later. Some data in the literature suggest that ovarian cancers could be slightly overrepresented in DS. Despite the rarity of ovarian dysgerminoma, our case is the fifth reported in DS. This case is the second one associated with a family history suggesting the possibility of a familial predisposition to cancer. A hypothesis explaining the development of dysgerminoma in DS is proposed.

Balanced complex chromosomal rearrangements (BCCR) with at least three chromosomes and three or more breakpoints: report of three new cases.

Balanced complex chromosomal rearrangements (BCCR) encompass a heterogeneous group of rare chromosomal aberrations. In this paper, we report three cases of BCCRs. In two the probands were referred for either genetic counseling or prenatal management. One case was ascertained after chromosome analysis performed because of psychiatric manifestations; this was an isolated finding. We also outline the molecular cytogenetic techniques, which were essential in confirming and precisely delineating the BCCRs identified in these patients. In addition the various aspects of genetic counseling for this type of chromosomal rearrangement, highlighting the details particular to each individual case are discussed. We discuss the classification for this type of chromosomal mutation.

De novo complex chromosomal rearrangements (CCR) involving chromosome 1, 5, and 6 resulting in microdeletion for 6q14 in a female carrier with psychotic disorder.

A 23-year-old obese woman with a psychotic disorder was found to have a de novo apparently balanced complex chromosomal rearrangement involving chromosomes 1, 5, and 6. Molecular cytogenetic analyses using high-resolution comparative genomic hybridization (HR-CGH) showed a microdeletion at 6q14 in a der(6). Application of HR-CGH facilitated detection of micro-rearrangement of all de novo apparently balanced complex chromosomal rearrangements (CCR) and supported the localization of the breakpoint. According to our knowledge, no constitutional interstitial microdeletion of chromosome 6q14 has been found associated with a schizoid-type phenotype.

[One carbon metabolism and trisomy 21: analysis of the genetic polymorphism]. / Métabolisme des substrats monocarbonés et trisomie 21: analyse de l'impact des polymorphismes génétiques.

Trisomy 21 is the most common chromosome abnormality characterized by the presence of three copies of chromosome 21 in the genome. The clinical disorder attributed to trisomy 21 is Down syndrome. Patients with Down syndrome are heterogeneous in their phenotypic expression. Due to the location of the cystathionine b-synthase gene on chromosome 21, and its involvement in one carbon metabolism, homocysteine levels have been found to be decreased in children with Down syndrome. The study of the regulation of one carbon metabolism in Down syndrome becomes important in light of possible normalization of the metabolic imbalance and the detection of increased sensitivity to therapeutic interventions. Thus, the importance of evaluating single nucleotide polymorphisms in genes involved in one carbon metabolism need to be addressed in individuals with trisomy 21. This review offers an analysis of the impact of these polymorphisms in Down syndrome and their possible implications for phenotypic heterogeneity.

Aspects of intracranial and spinal tumors in patients with Down syndrome and report of a rapidly progressing Grade 2 astrocytoma.

BACKGROUND: Brain tumors in patients with Down syndrome (DS) rarely are reported, and their behavior is not well known. METHODS: The authors report on a male patient age 19 years who had DS with diffuse astrocytoma (World Health Organization Grade 2) that recurred twice despite treatment, leading to a glioblastoma and, finally, to death in just over 2 years. The literature on brain tumors in patients with DS is reviewed. RESULTS: Although brain neoplasms were suspected to be in excess in patients with DS, the authors found only 36 patients with brain neoplasms and 2 spinal tumors. An unusual distribution of histologic tumor types, with an over-representation of germ cell and mesenchymal tumors and a lack of embryonal tumors, was observed, in agreement with what is known currently about the tumor profile of patients with DS. CONCLUSIONS: Cerebral tumors in patients with DS have a specific distribution and may behave differently compared with the general population. These features may be related to the gene dosage effect of oncogenes, antioncogenes, and genes involved in cerebral development due to the supernumerary chromosome 21.

[Breast cancer in women with trisomy 21]. / Les cancers mammaires des femmes trisomiques 21.

The population with Down's syndrome has a different cancer profile compared to the general population, even after taking into account issues of survival and ageing. Several solid tumours are unusually rare, whereas in contrast leukaemias are increased. In addition, few studies are available on this topic. We therefore decided to conduct a mortality study based on the INSERM national mortality statistics in France comparing over a 24 year period deaths from female breast cancer in the general French population with the cancer deaths in women with Down's syndrome. Only 5 deaths with Down's syndrome could be found compared to 68.98 expected based on national statistics. This clear reduction in risk agrees with other studies available in Down's syndrome patients. This observation could be partly explained by over expression of genes linked to gene dosage effects on chromosome 21, playing a role in cell growth, differentiation, survival and death. An additional protective effect could come from the marked and continued decreased exposure to oestrogens, starting in utero for women with trisomy 21 and lasting all over life.

[Aged parents and aging handicapped persons: a new situation, an attempt to respond]. / Parents âgés et handicapés vieillissants: une situation nouvelle, un essai de réponse.

The longevity increase which characterises the society evolution at the end of the 20th century, also concerns the handicapped people. The fact is particularly outstanding for mentally handicapped people such as the Down's Syndrome population. We are nowadays discovering the first generation of the "over 40 year-old people". Among the eldest, many of them have never left home as specialised structures were non existent when they were young. Even those, not many of them in that age group, who have been able to have access to a CAT and to profit by a specialised centre, cannot carry on working after their 35th birthday, because of their early ageing, and because of their tiredness. Therefore, they are early excluded from the CAT, they lose their advantage of being in a specialised centre and they finely have to go back home. Many parents of mentally handicapped people who live at home, even though they are not yet too old, seem to get more and more tired with their ageing advance, which, day after day, makes their unremitting action harder and harder towards their child who is also getting older. The makers relate the innovating and experimental initiative of a "Hameau Services", nowadays located at Sommières-du-Clain, a rural parish in the south of Vienne country, which offers to welcome still valid ageing parents and their mentally handicapped ageing child who lives in their own house. The collective services which are assured by the managing association, tend to relieve them in their daily material tasks in the aim of contributing to the prejudice of the unexpected arrival of the manifestations of the subordination through a proposition of a better life quality of the handicapped adult and his parents.

Failure of testicular development associated with a rearrangement of 9p24.1 proximal to the SNF2 gene.

In 46,XY individuals, testes are determined by the activity of the SRY gene (sex-determining region Y), located on the short arm of the Y chromosome. The other genetic components of the cascade that leads to testis formation are unknown and may be located on the X chromosome or on the autosomes. Evidence for the existence of several loci associated with failure of male sexual development is indicated by reports of 46,XY gonadal dysgenesis associated with structural abnormalities of the X chromosome or of autosomes (chromosomes 9, 10, 11 and 17). In this report, we describe the investigation of a child presenting with multiple congenital abnormalities, mental retardation and partial testicular failure. The patient had a homogeneous de novo 46,XY,inv dup(9)(pter-->p24.1::p21.1-->p23.3::p24.1-->qter) chromosome complement. No deletion was found by either cytogenetic or molecular analysis. The SRY gene and DSS region showed no abnormalities. Southern blotting dosage analysis with 9p probes and fluorescent in situ hybridisation data indicated that the distal breakpoint of the duplicated fragment was located at 9p24.1, proximal to the SNF2 gene. We therefore suggest that a gene involved in normal testicular development and/or maintenance is present at this position on chromosome 9.

Excessive glutamine sensitivity in Alzheimer's disease and Down syndrome lymphocytes.

In addition to clinical and neuropathological similarities between Alzheimer's disease and Down syndrome there are genetic and biochemical data which suggest common disease mechanism. Using an in vitro assay examining variations of the mitotic index in the presence or absence of various inhibitors or metabolites of purine and/or pyrimidine synthesis, we studied 19 Alzheimer disease patients and 16 patients with both Down syndrome and Alzheimer type dementia. A highly significant decrease in mitotic index in the presence of exogenous glutamine was noted in patients presenting an Alzheimer type dementia with or without associated Down syndrome. These findings suggest that glutamine sensitivity or some dysregulation of the glutamine/glutamate pathway may play a role in the pathogenesis of Alzheimer's disease. If these findings are confirmed, they would have important implications in the development of preventive strategies.

Molecular mapping of 21 features associated with partial monosomy 21: involvement of the APP-SOD1 region.

We compared the phenotypes, karyotypes, and molecular data for six cases of partial monosomy 21. Regions of chromosome 21, the deletion of which corresponds to particular features of monosomy 21, were thereby defined. Five such regions were identified for 21 features. Ten of the features could be assigned to the region flanked by genes APP and SOD1: six facial features, transverse palmar crease, arthrogryposis-like symptoms, hypertonia, and contribution to mental retardation. This region, covering the interface of bands 21q21-21q22.1, is 4.7-6.4 Mb long and contains the gene encoding the glutamate receptor subunit GluR5 (GRIK1).

In vivo folic acid supplementation partially corrects in vitro methotrexate toxicity in patients with Down syndrome.

Patients with Down syndrome have been found to have characteristic in vivo and in vitro methotrexate toxicity. The in vitro methotrexate toxicity characteristic of Down syndrome can be diminished by the in vivo administration of supplemental high doses of folic acid. A possible explanation for the increased sensitivity to methotrexate which has been documented in patients with Down syndrome may be due to imbalances in nucleotide pools which result from a gene dosage effect and to greater methylation demands. Supplemental folic acid may be beneficial by virtue of a down-regulation of excess gene activity and may also provide needed monocarbons.

[Metabolic anomalies in trisomy 21: a method for analyzing lymphocyte cultures]. / Anomalies métaboliques dans la trisomie 21: méthode d'analyse sur cultures de lymphocytes.

Using a method of analysis which consists in the evaluation of the mitotic index of lymphocyte cultures to which different metabolites and anti-metabolites have been added, we studied various forms of mental retardation due to a chromosomal aberration and observed specific biochemical imbalances. Methotrexate sensitivity is characteristic of trisomy 21. A significant difference in purine synthesis pathway was observed between patients with Down syndrome without complications and those presenting with additional psychotic features. Inspite of a gene dosage effect for genes intervening in purine synthesis, lymphocytes from psychotic trisomy 21 patients seem unable to complete inosine synthesis. Lymphocytes from patients with Alzheimer's disease with or without trisomy 21 are excessively sensitive to exogenous glutamine.

Differences in purine metabolism in patients with Down's syndrome.

Three enzymes intervening in de novo purine synthesis, as well as cystathionine B-synthetase, have been mapped to chromosome 21. In order to gain a better understanding of purine synthesis anomalies in Down's syndrome, the present authors studied the variations in mitotic index of lymphocyte cultures to which various inhibitors or metabolites of purine synthesis had been added. In spite of common gene dosage effects, unexpected and highly significant differences were noted between Down's syndrome patients without complications and those presenting with additional psychotic features. In Down's syndrome patients without complications, a highly significant decrease in mitotic index was noted in the presence of exogenous inosine. A significant decrease in the presence of adenosine and guanosine was also noted. These findings are in keeping with the expected metabolic repercussions of genes mapped to chromosome 21. In Down's syndrome patients with psychotic complications, the in vitro reactions were quite different. A paradoxal increase in mitotic index was noted in the presence of inosine and of adenosine, but the response to guanosine did not differ from that observed in normal controls. These findings were unexpected and seem to indicate that, in spite of the gene dosage effect, psychotic Down's syndrome patients are unable to compensate abnormal purine synthesis and resulting imbalances. Furthermore, a marked difference in purine metabolic reactions was noted between Down's syndrome patients receiving supplemental folic/folinic acid and those on no therapy. This suggests that some modulation of the gene dosage effect may be possible.

[Brain morphometry using MRI in Cri-du-Chat Syndrome. Report of seven cases with review of the literature]. / Morphométrie encéphalique en irm dans la maladie du chat. A propos de sept patients, avec revue de la littérature. Association pour la recherche sur la sclérose en plaques.

The authors present the results of a morphometric study of the brain of 7 patients with cat cry syndrome, explored with Magnetic Resonance Imaging (MRI). A method is proposed in order to facilitate the identification of the anatomical slices. A characteristic anomaly is observed as a marked atrophy of the brainstem predominating at the pontine level and associated with a small cerebellum, atrophic middle cerebellar peduncles and cerebellar white matter. This apparently systematized atrophy obvious in children, seems similar to the one observed in patients presenting a olivopontocerebellar atrophy, possibly correlating with disturbance of coordination and developmental delay in motility as observed in these patients. This does not implicate the same subjacent functional neuroanatomical pathways.

No significant effect of monosomy for distal 21q22.3 on the Down syndrome phenotype in "mirror" duplications of chromosome 21.

Three Down syndrome patients for whom karyotypic analysis showed a "mirror" (reverse tandem) duplication of chromosome 21 were studied by phenotypic, cytogenetic, and molecular methods. On high-resolution R-banding analysis performed in two cases, the size of the fusion 21q22.3 band was apparently less than twice the size of the normal 21q22.3, suggesting a partial deletion of distal 21q. The evaluation of eight chromosome 21 single-copy sequences of the 21q22 region--namely, SOD1, D21S15, D21S42, CRYA1, PFKL, CD18, COL6A1, and S100B--by a slot blot method showed in all three cases a partial deletion of 21q22.3 and partial monosomy. The translocation breakpoints were different in each patient, and in two cases the rearranged chromosome was found to be asymmetrical. The molecular definition of the monosomy 21 in each patient was, respectively, COL6A1-S100B, CD18-S100B, and PFKL-S100B. DNA polymorphism analysis indicated in all cases a homozygosity of the duplicated material. The duplicated region was maternal in two patients and paternal in one patient. These data suggest that the reverse tandem chromosomes did not result from a telomeric fusion between chromosomes 21 but from a translocation between sister chromatids. The phenotypes of these patients did not differ significantly from that of individuals with full trisomy 21, except in one case with large ears with an unfolded helix. The fact that monosomy of distal 21q22.3 in these patients resulted in a phenotype very similar to Down syndrome suggests that the duplication of the genes located in this part of chromosome 21 is not necessary for the pathogenesis of the Down syndrome features observed in these patients, including most of the facial and hand features, muscular hypotonia, cardiopathy of the Fallot tetralogy type, and part of the mental retardation.

DNA polymorphism analysis in families with recurrence of free trisomy 21.

We used DNA polymorphic markers on the long arm of human chromosome 21 in order to determine the parental and meiotic origin of the extra chromosome 21 in families with recurrent free trisomy 21. A total of 22 families were studied, 13 in which the individuals with trisomy 21 were siblings (category 1), four families in which the individuals with trisomy 21 were second-degree relatives (category 2), and five families in which the individuals with trisomy 21 were third-degree relatives, that is, their parents were siblings (category 3). In five category 1 families, parental mosaicism was detected, while in the remaining eight families, the origin of nondisjunction was maternal. In two of the four families of category 2 the nondisjunctions originated in individuals who were related. In only one of five category 3 families, the nondisjunctions originated in related individuals. These results suggest that parental mosaicism is an important etiologic factor in recurrent free trisomy 21 (5 of 22 families) and that chance alone can explain the recurrent trisomy 21 in many of the remaining families (14 of 22 families). However, in a small number of families (3 of 22), a familial predisposing factor or undetected mosaicism cannot be excluded.

Segregation of three reciprocal translocations in the same family: t(3;4), t(5;10), and t(15;21).

A male infant with static antenatal encephalopathy and epilepsy was found to have a duplication of 5p12----5pter and deficiency of 10p13----10pter. Each of his parents was a carrier of a balanced reciprocal translocation. A third translocation was found in the maternal grandfather. The pedigree of each translocation and the segregation of parental reciprocal translocations are discussed.