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At least 19 recordsLinked to original sources
PubMed1977

[Chromosome 8 : complete trisomy and segmental trisomies].

The phenotypic effects of trisomy of various segments of chromosome 8 have been recognized through the analysis of twelve different patients: five mosaic cases of trisomy 8, one case of trisomy for the short arm and the proximal segment of the long arm, two cases of trisomy for a portion of the short arm, and four cases of trisomy for the terminal segment of the long arm. Analysis of the data from the literature and of these personal observations allows the definition of three syndromes: trisomy 8, trisomy 8p and 8q proximal, and trisomy 8q terminal. Three clinical signs are common to the three syndromes: vertebral anomalies, depression of the mesosternum, and bulging of the forehead. This suggests that different segments of chromosome 8 carry genes affecting osseous growth. Trisomy 8p causes, in addition to severe mental deficiency, a thick nose, a large mouth, and microcephaly. Other clinical signs can be assigned to three groups corresponding to the short arm, the proximal part, and the distal part of the long arm.

Abnormalities, Multiple↗
PubMed1977

Partial trisomy 8q in half-sisters with distinct dysmorphic patterns not similar to the trisomy 8 mosaicism syndrome.

Two cases of partial trisomy 8q are presented. Common clinical features included severe mental and physical retardation, a prominent and short forehead, widely set mongoloid eyes, broad, flat nose with short septum, short upper lip, misshapen ears, a funnel chest, hypertrichosis of the back, coxa valga, and short fingers with brachymesophalangy and clinodactyly of the little fingers. Moreover, Case 1 had a frontal meningocele and bilateral talipes equinovarus, and Case 2 had a ventricular septal defect. The chromosome aberration in the two girls arose from a maternal balanced translocation, t(8;18) (q2309;p113). Since the major clinical features of mosaic trisomy 8 are absent in the two girls and in other cases of partial trisomy, both for the distal segment of the long arm and for the short arm of chromosome 8, it is concluded that trisomy of the proximal part of the long arm of chromosome 8 causes most of the clinical findings of trisomy 8 mosaicism syndrome.

Abnormalities, Multiple↗
PubMed1978

The ratio of de novo unbalanced translocation to 47, trisomy 21 Down syndrome. A new method for human mutation surveillance and an apparent recent change in mutation rate resulting in human interchange trisomies in one jurisdiction.

The Down syndrome phenotype may be associated with, among other genotypes, an unbalanced Robertsonian translocation producing an "interchange trisomy" with 46 chromosomes, or 47, trisomy 21. Translocations, like specificlocus point mutations, result from a direct change in structural chromosome elements. In contrast 47, trisomy 21 results from meiotic non-disjunction. Mutation rates for interchange trisomies may be followed indirectly by determining the ratio of instances of Down syndrome associated with a new translocation mutation to those produced by 47, trisomy 21, which accounts for the bulk of the Down syndrome phenotype. This genotypic ratio can be analyzed in data from cytogenetic laboratories, clinics, and chromosome registries and does not depend upon intensive chromosome screening of newborn populations. A similar approach can be adopted to follow trends in Patau syndrome. The genotypic ratio, stratified by maternal age, may in addition, provide a sentinel index for changes in human specific-locus mutations and perhaps other adverse health consequences. Analysis of data from the New York State-North-eastern chromosome registry revealed a two- to three-fold increase in the genotypic ratio for both Down syndrome and Patau syndrome for individuals born in 1973, 1974 and 1975 compared to those born in earlier years.

Down Syndrome↗
PubMed1979

Partial trisomy 18q12, due to intrachromosomal duplication, is not associated with typical 18 trisomy phenotype.

Partial 18q12 trisomy, due to intrachromosomal duplication, was found in a severely mentally retarded boy. The finding of nonspecific dysmorphism in this patient demonstrates that trisomy of band 18q12 is accompanied by neither a full nor an incomplete 18 trisomy phenotype, indicating that this phenotype may be due solely to trisomy of the 18q11 band.

Abnormalities, Multiple↗
PubMed1978

Partial trisomy 18q in a newborn with typical 18 trisomy phenotype.

This paper describes a case of partial trisomy of almost the entire long arm of chromosome 18 in a newborn with classic trisomy-18 phenotype, resulting from a de novo unbalanced 181/21p translocation: karyotype: 46,XX,-21,t(18;21)(18qter leads to 18q11 ::21p12 leads to 21qter). A review of the other reported cases of partial trisomy 18 suggests that a critical segment in chromosome 18, corresponding to bands q11-q12, might be responsible for most of the signs of trisomy 18, including failure to thrive and early death.

Chromosome Banding↗
PubMed1978

Trisomy 16p in a liveborn infant and a review of partial and full trisomy 16.

An abnormal female infant, who survived for 10 months with almost complete trisomy 16p and monosomy of sub-band 21q22.3, is described. The chromosome anomaly was the result of an unbalanced segregation of a maternal balanced translocation t(16;21)(p11;q22.3). The partial monosomy was considered to have had little or no adverse phenotypic effect. Cases with trisomy of chromosome 16 material are reviewed. It appears that while full trisomy 16 always results in early spontaneous abortion, trisomy 16p or 16q may be compatible with limited postnatal survival.

Chromosomes, Human, 16-18↗
PubMed1977

Regular G21-trisomy in 3 sibs from mother with trisomy 21 mosaicism.

This paper describes a family with 3 affected sibs with regular trisomy 21 Down syndrome. The condition seems to be transmitted from a phenotypically normal mother in whom G-trisomy mosaicism was identified. Giemsa banding depicted trisomy 21 mosaicism in cells from the mother. Chromosomes from the children showed a trisomy 21 in all the cells analysed.

Adolescent↗
PubMed1979

Trisomy 12p syndrome: de novo occurrence of mosaic trisomy 12p in a mentally retarded boy.

The first case of trisomy of probable 12p mosaicism originated de novo is presented. Comparison of the clinical findings of this patient with those of previously described cases of 12p trisomy derived from translocated chromosomes indicates that the symptoms of 12p trisomy are: (1) normal birth weight and physical development, (2) severe psychomotor retardation and generalized hypotonia, (3) peculiarly round face with prominent cheeks, hypertelorism, epicanthus, broad, flat nasal bridge, short nose with anteverted nostrils, large philtrum, broad, prominent lower lip, and (4) poly(syn)dactyly of feet.

Chromosome Banding↗
PubMed1977

Partial trisomy 8 (trisomy 8q2106 leads to 8qter).

A case of trisomy for part of the long arm of chromosome 8, confirmed by G-banding analysis, in a white male infant is described. The mother carried a reciprocal translocation between chromosome 8 and chromosome 13 (46,XX,t(8;13),(q21:q34). The patient had inherited the translocated chromosome 13 and was thus trisomic for the distal half of the long arm of chromosome 8. He had many of the clinical features of the full trisomy 8 syndrome. As compared with previously reported cases with trisomy of the distal end of chromosome 8, he was more dysmorphic and showed greater developmental retardation.

Abnormalities, Multiple↗
PubMed1979

Partial trisomy of chromosome 3 (3q12 leads to qter) owing to 3q/18p translocation. A trisomy 3q syndrome.

In four previously reported patients with partial 3q trisomy, only a small portion of 3q was trisomic (3q21 leads to qter or 3q25 leads to qter). Clinical features in these cases have included the following: low-set ears, mongoloid slant of eyes, hypertelorism, cleft palate, webbed neck, simian creases, short finger, clinodactyly, hypotonia, and low-set hairline. Cytogenetic studies of a premature, 1,680-g female infant with with these clinical features showed this extra material to be part of the long arm of chromosome 3 (3q12 leads qter), which resulted in partial trisomy for this segment, ie, 46,XX,-18, +t (3;18) (q12;p11). Although a larger portion of 3q was involved in this case, the clinical picture was similar to other cases of 3q duplication with or without 3p deletion.

Abnormalities, Multiple↗
PubMed1977

Partial trisomy 21. Further evidence that trisomy of band 21q22 is essential for Down's phenotype.

Cytogenetic analysis of a 6-year-old girl with moderate mental retardation revealed 46 chromosomes with a tandem translocation (21;21) resulting in a partial trisomy 21. Only the terminal band 21q22 was not in triplicate. G-, Q-, R-, and C-banding techniques and silver nitrate staining of the nucleolus organizer regions (NORs) were used to identify this chromosome fully. The phenotype of the patient was not typical for Down's syndrome, providing additional evidence that trisomy of band 21q22 is pathogenetic for the phenotype of Down's syndrome. This is also a new example in human pathology of a stable 'dicentric' chromosome in which one of the centromeric constrictions appears to be nonfunctional.

Centromere↗
PubMed1977

Familial translocation with partial trisomy of 13 and 22: evidence that specific regions of chromosomes 13 and 22 are responsible for the phenotype of each trisomy.

A newborn infant with clinical and pathological findings typical trisomy 13 and 22 syndromes had an extra chromosome which was a derivative chromosome from maternal balanced translocation affecting Nos. 13 and 22; 47,XY,+der(22),t(13:22)(q22:q12)Mat. The presence of extra specific euchromatic regions of No. 13(13q22 and/or 13q34) and No. 22 (22q11) seem to be responsible for the trisomy 13 and 22 syndromes.

Abnormalities, Multiple↗
PubMed1978

Gene dosage effect for human triosephosphate isomerase and glyceraldehyde-3-phosphate dehydrogenase in partial trisomy 12p13 and trisomy 18p.

An 8-year-old girl with profound mental retardation and a neurologic syndrome associated with morphologic abnormalities was found to have a supernumerary small submetacentric chromosome. Several members of her family carried a balanced translocation t(12;18)(p12;q11), and the child's karyotype could be explained by 3:1 maternal segregation (tertiary trisomy). The proband was trisomic for 12p13 and 18p. A gene dosage effect was demonstrated for triosephosphate isomerase and glyceraldehyde-3-phosphate in erythrocytes and leukocytes allowing us to assign the corresponding loci to the tip of the chromosome 12 short arm.

Carbohydrate Epimerases↗
PubMed1978

Double trisomy as a mosaic. Case history (48, XYY, + 21/47,XY, +21) and survey of the literature of mixed autosomal-gonosomal trisomies.

The case of a boy is reported showing the typical symptoms of Down's syndrome, in whom the chromosome analysis revealed a mosaic karyotype: 50% 48,XYY,+21/50% 47,XY,+21. Findings of 92 cases from the literature are summarized to show the frequencies of double gonosome-autosome aneuploidies compared with single trisomies. Referring to the different chromosomes involved, the aneuploid cell formation, the frequencies of combinations, as well as the tendency to mosaic formation are analyzed. The age of parents at the time of birth and the life expectancy are described as well as the clinical symptoms. Theories concerning the origin of double aneuploidies are discussed.

Aneuploidy↗