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M O Rethoré

Publications and source records attributed to M O Rethoré.

At least 19 recordsLinked to original sources
PubMed1995

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).

Adolescent↗
PubMed1994

[Metabolic anomalies in trisomy 21: a method for analyzing lymphocyte cultures].

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.

Amino Acid Sequence↗
PubMed1993

[Brain morphometry using MRI in Cri-du-Chat Syndrome. Report of seven cases with review of the literature].

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.

Adolescent↗
PubMed1992

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.

Amino Acids↗
PubMed1992

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.

Chromosomes, Human, Pair 21↗
PubMed1992

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.

Adult↗
PubMed1992

[Amino acids and trisomy 21].

The relative concentrations of plasmatic and urinary amino acids were analysed in 79 trisomic-21 patients, 322 mentally retarded non-trisomic patients, and 206 controls. No true amino acidopathy was found in 21-trisomy, but in plasma a deficit of serine and an excess of cysteine and lysine are highly significant. Excesses of cysteine, methionine, tyrosine, and methyl-histidine are also typical in urine. The increased activity of superoxide-dismutase, cystathionine-beta-synthase, and purine synthesis enzymes, together with the sensitivity to methotrexate, atropine, and dysthyroidism, are in accordance with this shift of equilibrium. A nutritional compensation seems worth investigating.

Amino Acids↗
PubMed1991

Metabolic anomalies in cri du chat syndrome (5p-) lymphocytes and de novo purine synthesis.

Having previously demonstrated that patients with cri du chat, 5p- syndrome, have a highly significant excess of the plasmatic and urinary relative amount of asparagine and aspartate, the authors tested the hypothesis according to which this excess could be in relation with a defect of purine metabolism. Using a previously reported in vitro assay, they found a paradoxal increase in the mitotic index in the presence of L-alanosine in lymphocyte cultures of patients with 5p- who were on no medication. They also observed particularly severe toxicity to HAT medium. This response, apparently characteristic for 5p- syndrome, was highly significant when compared to the one observed in samples of normal controls, of patients with mental retardation of various etiologies, patients with Down syndrome or with Xqfra syndrome. When patients with cri du chat syndrome received inosine with folinic acid, an inversion of their response to alanosine was observed as well as the normalization of their response to HAT medium. These findings suggest that deletion of 5p14-5p15 leads to some impairment of de novo purine synthesis, the implications of these findings are discussed.

Adolescent↗
PubMed1990

Risk of Down syndrome in relatives of trisomy 21 children. A case-control study.

We conducted a case-control study in families of Down syndrome children with classical trisomy 21 (n = 188) and in a control group of families of children referred to the same hospital for benign diseases (n = 185). The low sibling number does not allow any conclusion about the risk for sibs but our results do not support an increased incidence of Down syndrome among second and third degree relatives of trisomy 21 children. The choice of the control group and the restriction to close relatives protect us against biases which may have interfered in previous studies reporting recurrence in families.

Abortion, Spontaneous↗
PubMed1990

[r14 syndrome without major dysmorphism].

An 8-year-old boy, mentally retarded and epileptic since the age of six months, was found carrier of ring 14 chromosome. A dystrophy of the eye fundi was observed (whitish puncta of the macula); except for the "almond shaped eyes", there was no obvious dismorphism.

Abnormalities, Multiple↗
PubMed1990

[Cri-du-chat disease: plasma and urinary amino acids].

Ten cases of cri du chat disease due to a del(5)(p14p15) were observed. A highly significant excess of the plasmatic and urinary relative amount of asparagine + aspartate was detected. A highly significant excess of the relative amount of histidine was also noted in the urine but not in the plasma. Excess of asparagine + aspartate could be related to a disorder of purine metabolism. The urinary excess of histidine could be related to a disorder of the aminoacid catabolism.

Adolescent↗
PubMed1989

Absence of familial association between dementia of Alzheimer type and Down syndrome.

The aim of this study was to test whether there is an excess of dementia of Alzheimer type (DAT) cases in Down syndrome (DS) relatives. We conducted a case-control study in families of DS children with classical trisomy 21. A control group was constituted of families of children referred to the same hospital for benign diseases. Families of 188 DS children and 185 controls were recruited. We obtained vital statistics on 1,850 (response rate 82%) grandparents and great-grandparents in the DS group and 1,525 (69%) in the control group. Rates of possible severe dementia were calculated on ancestors over age 60 years with available data on mental function, 1,336 in the DS group and 1,113 in the control group. Rates of possible severe dementia were similar in the two groups: 5.6% (78 cases) in DS and 6.2% (66 cases) in control. Dementia with insidious onset suggestive of DAT was observed in 2% (28 cases) of DS ancestors and 2.6% (28 cases) of control ancestors. Our results argue against an excess of dementia cases with insidious onset suggestive of DAT in families of children with classical trisomy 21.

Age Factors↗
PubMed1989

Pure partial trisomy of the short arm of chromosome 5.

We describe a male infant with multiple dysmorphic features who is trisomic for chromosome segment 5p13.32----5p14.2 as a result of recombination aneusomy. His father is a balanced carrier of an inverted insertion of this chromosome segment. The clinical features of this patient are compared with those of other patients with isolated partial 5p trisomy reported in the literature.

Chromosome Banding↗
PubMed1989

Molecular definition of de novo and genetically transmitted WAGR-associated rearrangements of 11p13.

We describe a family in whom the phenotypically normal father carries a balanced insertional translocation, ins(14;11)(q23;p12p14). This individual fathered three mentally retarded children, two with a del(11)(p13) and one with a dup(11)(p13). Two other cases of a de novo del(11)(p13) are also described. All four del(11)(p13) cases presented with WAGR, a complex syndrome associated with a predisposition to Wilms' tumor (WT), aniridia (A), genitourinary abnormalities (G), and mental retardation (R). Using an approach combining karyotype analysis, determination of the gene copy number, and RFLP studies employing five 11p13 DNA markers, we were able to define the chromosomal rearrangement involved in each case. Analysis of these WAGR deletions provides further subdivision of band p13 on chromosome 11.

Adult↗
PubMed1989

[Nucleolus organizer region--centromere translocation].

A karyotype 45,XX,-13,-15,+psudic (13;15)(p12.9;11.200) was observed in a young woman after two spontaneous miscarriages. After R-, C-, and NOR - banding - the rearranged element was shown to include: the long arm, the active centromere, and the NOR of chromosome 13, followed by the inactivated centromere, and the long arm of chromosome 15.

Abortion, Spontaneous↗
PubMed1988

Eleven new cases of del(9p) and features from 80 cases.

We report 11 cases of del(9p) and review 69 previously published ones. Of the 80 cases, 39 have a del(9p) as the sole anomaly. The symptoms are typical and diagnosis should be suspected at birth. The sex ratio does not appear to be unbalanced. A cardiac murmur is often present but surgery is rarely necessary. Mean IQ is 48. The number of reported cases with an associated trisomy has previously been underestimated. Death in infancy, owing mainly to gross visceral malformations, occurs more often in cases of del(9p) with another unbalanced chromosome segment (16/41) than in cases of del(9p) as the sole anomaly (1/39).

Abnormalities, Multiple↗