La trisomie 4p

Résumé Trois nouveaux cas de trisomie 4p sont rapportés. Deux observés chez des germains sont liés à une translocation maternelle t (4;15). Le troisième cas est dû à une duplication en miroir du bras court du chromosome 4, il s'agit du premier cas de trisomie 4p sans remaniement parental équilibré. Les principales caractéristiques cliniques et chromosomiques du syndrome sont étudiées à partir des observations de la littérature.

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Trisomy 4pThree new observations

Summary Three new observations of trisomy 4p are reported. Two are due to a maternal translocation t(4;15). The third is due to a mirror duplication, it is the first case of trisomy 4p without balanced parental rearrangement. The very characteristic phenotype is compared to that of 13 other patients already reported in the literature.

     

Phenotypic and cytogenetic spectrum of 9p trisomy

Trisomy 9p is one of the most frequent autosomal anomalies compatible with long survival rate. The spectrum of clinical severity in trisomy 9 roughly correlates with the extent of trisomic chromosome material. Trisomy 9p is a clinically well delineated syndrome and of all stigmata craniofacial dysmorphism is most specific. In this study we report five cases with de novo trisomy 9p. The study aimed at the identification of the genotype/phenotype correlations in patients with different breakpoints. GTG banding, DAPI stain, whole chromosome paint, centromere, telomere and 9p21 specific locus probes demonstrated that partial trisomy 9p in case 1 was due to isochromosome 9p with translocation of the long arm of re-arranged chromosome 9 onto the short arm of chromosome 13, cases 2 and 3 had intrachromosomal duplication of the short arm of chromosome 9 [dup(9)(p21p24)], case 4 had "classical" 9p trisomy and case 5 had duplication of whole short arm and part of the long arm of chromosome 9 (partial 9 trisomy). Although cases 1 to 4 had trisomy involving 9p, cases 1 and 2 exhibited the classical clinical manifestations of 9p trisomy, while cases 3 and 4 had additional features overlapping with Coffin-Siris syndrome. The present study strengthens the association of Coffin-Siris syndrome and 9p, the significance of such observations may point to possible gene location of Coffin-Siris syndrome on 9p. Case 5 had additional manifestations more than those typical of trisomy 9p which could be due to duplication of 9q21 region. Wide gap between 1st and 2nd toes, observed in the studied cases, can be added to the phenotype of this trisomy. Three of our cases had brain malformations, case 3 had dilated ventricles with hypogenesis of corpus callosum, case 4 had agenesis of corpus callosum, and case 5 had Dandy-Walker malformation. We also suggest that dosage effects of genes located in 9pter-q22 contribute to the etiology of Dandy-Walker syndrome. We recommend MRI studies as a routine in all cases with trisomy 9p.     

Syndrome +12p

Summary Familial 12/15 translocation with a child trisomic for the short arm of chromosome 12 (segment p 12.1pter) is reported. The clinical picture of the child is strikingly similar to previous reports of 12p trisomy. The main symptoms of 12p syndrome are defined.     

Partial trisomy 6p

Summary A case of trisomy 6p216pter resulting from a maternal balanced t(2;6)(p25;p21) translocation is reported. The main clinical abnormalities were psychomotor retardation, hypotrophy, blepharophimosis, nystagmus, high nasal bridge, small mouth, sacral dimple, and systolic murmur. Other anomalies might have been due to partial 2p monosomy. Comparison with seven other cases of trisomy 6p allowed the delineation of a clinical entity. Direct proof of the localization of HLA genes was given by the presence of three haplotypes in the index patient.     

Trisomy 11p15 and Beckwith-Wiedemann syndrome. A report of two cases

Summary Two patients with trisomy 11p15 and features of Beckwith-Wiedemann syndrome are reported. The first is a female infant with gigantism, macroglossia, abdominal hypotonia with umbilical hernia, moderate mental retardation, malformative uropathy, and atrial septal defect. Trisomy 11p15 was due to de novo duplication. The second patient was a stillborn (32–33 weeks pregnancy) with an abnormal tongue, posterior diaphragmatic eventration, inner organ congestion mainly of the adrenals. Trisomy 11p15 was due to a t(4;11)(q33;p14)pat. The association of trisomy 11p15 and Beckwith-Wiedemann syndrome is discussed with regard to cytogenetic data and the gene content of 11p, notably the genes coding for insulin and predisposition to Wilms tumour.     

Partial trisomy 10p.

It is reported on a boy of 4 years 9 months with trisomy of the distal part of the short arm of a chromosome 10, due to a balanced 7/10 translocation in the father. Besides multiple minor dysmorphias the patient showed severe mental retardation, small stature, hypotonia, retarded bone age. The high and bulky forehead was especially remarkable, because this sign has also been noted in formerly reported cases with trisomy 10p.     

Partial trisomy 10p

Summary It is reported on a boy of 4 years 9 months with trisomy of the distal part of the short arm of a chromosome 10, due to a balanced 7/10 translocation in the father. Besides multiple minor dysmorphias the patient showed severe mental retardation, small stature, hypotonia, retarded bone age. The high and bulky forehead was especially remarkable, because this sign has also been noted in formerly reported cases with trisomy 10p.     

Partial trisomy 10p of paternal origin. 2 new cases in 2 different families]

Two unrelated patients with partial trisomy 10p due to a paternal balanced translocation are reported. Though the sizes of the trisomic segment are not identical, both patients show: severe growth retardation, important psychomotor retardation and a dysmorphic mouth recalling a "tortois mouth". These observations are compared to twelve others from the literature.     

Partial trisomy 17q and monosomy 9p due to a familial translocation.

Described is an infant with partial trisomy 17q and monosomy 9p [46,XX,-9,+der(9)t(9;17)(p21;q23)] due to adjacent-1 segregation of a maternal balanced reciprocal translocation. Characteristic clinical features of both partial 17q trisomy and monosomy 9p are present, but the former syndrome is less recognisable in this infant than in previously reported cases due to the concomitant 9p monosomy.     

Partial 4q trisomy. Apropos of 3 cases.

Three observations of partial trisomy 4q are reported: the first due to a familial translocation the second to a de nove translocation, the third to a "mirror" duplication. The very characteristic phenotype is compared to that of 4 other patients already reported in the literature. The most evocatory symptoms include: absent or poorly indicated nose bridge; pursed lips; shortness of the philtrum; and constant existence of a fold on the antitragus continuing the anthelix reachinghe insertion of the pinna.     

‘Complete’ trisomy 5p; de novo translocation t(2;5)(q36;p11) with isochromosome 5p

Summary A case of complete trisomy 5p due to a de novo translocation t(2;5)(q36;p11) with an isochromosome 5p is described. Complete trisomy 5p has been reported only once (Brimblecombe et al., 1977). The confusing literature relating to partial trisomy 5p is reviewed. Comparison of our case with the patients reported by Brimblecombe et al. (1977) and by Opitz and Patau (1975) is suggestive for a distinct clinical syndrome if (almost) the complete short arm of chromosome 5 is present in a trisomic state. Unfortunately the clinical findings in the case of Brimblecombe (1966, 1977) are poorly documented. The main features of this syndrome are: macrocephaly, psychomotor retardation, hypotonia, postnatal growth failure, tracheobronchial involvement, mongoloid slant of the eyes, epicanthus, low-set ears, depressed nasal bridge, short first toe, and seizures.     

Partial trisomy 4q in two unrelated cases

Summary Two unrelated cases of 4q trisomy are described with trisomic segment 4q254qter. The most conspicuous symptoms are psychomotor retardation, microcephaly, malformed ears, retrognathia, finger and toe malformations and cryptorchism in a male. Both cases are compared with 19 previously reported ones.To whon offprints requests should be sent     

Partial duplication of the short arm of chromosome 9 (p13→p22) in a child with typical 9p trisomy phenotype

Summary A 3-year-old girl with duplication 9 (p22p13) is reported. The presence of a classical 9p trisomy phenotype in this patient suggests that this region (or part of it) is responsible for the major, typical clinical stigmata of this partial autosomal trisomy syndrome.     

Secondary trisomy 1 q due to a reciprocal maternal translocation]

The authors report a case of partial trisomy 1 q due to a maternal balanced translocation : t(1 ; 4) (q 32 : p 16). The evocative malformations of trisomy 1 q and monosomy 4 p are discussed and compared to seven others from the literature. Then the interest of the chromosomical prenatal diagnosis and the significance of familial genetic studies are showed.     

Severe psychomotor retardation in a boy with a supernumerary derivative chromosome resulting in partial trisomy 21 and partial trisomy 7p

We report on a 12-year-old boy with a supernumerary chromosome der(21)t(7; 21)(p21; q21.3)mat, resulting in a partial trisomy 21 and a partial trisomy 7p. The patient has a severe psychomotor retardation. Although he has most of chromosome 21 in three copies, he does not have a phenotype of Down syndrome (DS). In addition to cytogenetic analysis, molecular analysis confirmed that the "DS critical region" on chromosome 21 (21q22) is not present in three copies, since the breakpoint of the partial trisomy 21 was found to be located distal to the marker locus D21S145 but proximal to D21S226. The patient's severe mental retardation is probably due to the small telomeric 7p trisomy, having the breakpoint between markers D7S507 and D7S488. In comparison with previously published cases of partial trisomy 7p, the phenotype of this patient indicates that there is a region around the distal part of band 7p21 that in three copies might contribute to many of the facial features common to patients with partial trisomy 7p.     

Type and contretype signs in monosomy and trisomy 9p. On a case 46,XY, del (9) (pter yields p12:).

A 15-month-old male with a partial monosomy 9p is reported. The comparative analysis with other cases of 9p monosomy demonstrates a typical phenotype which when compared to that of 9p trisomy, permits the delineation of fifteen "type and contretype" signs.     

Trisomy 20p: case report and genetic review

Partial trisomy for the distal part of the short arm of chromosome 20 reported in a girl aged 11/2 years with typical craniofacial dysmorphies and psychomotor retardation. The trisomy resulted from a paternal translocation t(14;20) (q32.3;p11.1). The review of 25 cases of partial trisomy 20p showed that most cases (22 : 25) were due to parental translocations. Predominant involvement of small chromosomes in translocations with chromosome 20 was also detected.     

Tertiary trisomy (22q11q),47,+der(22),t(11;22)

Summary We describe a case of tertiary trisomy (22q11q) 47,XX,+der(22),(22pter22q13: : 11q2511qter) in a child with mental retardation, cleft palate, and congenital heart disease resulting from 3: 1 meiotic nondisjunction in a maternal (11;22) translocation carrier. The clinical findings in previously reported cases are reviewed and compared with the features of reported patients with partial trisomy 11q and trisomy 22 syndromes. Half of the ten reported families had additional balanced translocation carriers who may have an increased risk of having a liveborn child with an MCA/MR syndrome, although none have been reported to date.     

Familial trisomy 11p resulting from a balanced paternal translocation: 3 new cases including first trimester diagnosis

Three related new cases with almost complete trisomy 11p due to paternal balanced translocation 46, XY, t(7; 11) (q36.1; p11.1) are reported. The proband (Case 1) was a malformed stillborn with exomphalos, case 2 was diagnosed in the first trimester by direct chromosome preparations from chorionic villi, and confirmed on fetal products after termination of pregnancy. Case 3, a cousin to cases 1 and 2, was a 29-weeks-old fetus with omphalocele discovered at ultrasound. Literature reports of trisomy 11p are reviewed with regard to those new cases, and the possible relationship of this chromosome imbalance with the Beckwith-Wiedemann Syndrome is discussed.     

Viability of trisomy 12 cells in mouse chimaeras

Summary Mouse aggregation chimaeras consisting of trisomy 12 and normal euploid cells were produced. The analysis of one trisomy 12euploid chimaera, using biochemical and cytological markers, showed that the trisomic cells were able to participate in the formation of most tissues including the ovary. On the other hand, no trisomy 12 cells were found in lymphocyte populations, which is most likely due to early selection in this particular cell lineage. The viability of two adult trisomy 12 chimaeras demonstrates that trisomy 12 cells are able to develop beyond the fetal stage which is not observed in completely trisomic fetuses.Furthermore, these chimaeras did not show any sign of a trisomy 12 syndrome, indicating that the trisomy 12 cells were functionally integrated and participated normally in the differentiation of the various tissues. Our results suggest that trisomy 12 in the mouse is not autonomously cell lethal but can be rescued and is perfectly viable in the presence of normal diploid cells.This article is dedicated to the memory of Prof. A. Gropp