Partial trisomy 15q due to maternal translocation t(7;15)(q35;14)]

Partial trisomy for the long arm of chromosome 15 was detected in a 21-year-old girl with severe growth and mental retardation. A balanced reciprocal translocation - t(7;15)(q35;q14) - is present in the mother.     

Partial trisomy of chromosome 21 by maternal translocation t(15;21) (q26.2; q21)]

A balanced reciprocal translocation, t(15;21) (q262;q21) was observed in the mother and maternal grandfather of two patients. The propositus, who received the abnormal chromosome 15 from his mother, is trisomic for the distal part of chromosome 21, and his phenotype is that of classical trisomy 21. His sister, who is trisomic for the proximal part of 21q, is slightly retarded but developmentally normal otherwise.     

A jumping translocation (5p;15q), (8q;15q), and (12q;15q) (author's transl)]

Three balanced karyotypes (5p;15q), (8q;15q), and (12q;15q) were found simultaneously in a child with the Willi-Prader syndrome. The hypothesis is presented of a "jumping# translocation by affinity of telomeric and interstitial palindromes. The relationship between the Willi-Prader syndrome and a juxtacentric anomaly of the long arm of chromosome 15 is discussed.     

Mosaic and non-mosaic trisomy 15q2

Two unrelated patients are presented. In the first mosaicism with normal cells and cells trisomic for the distal long arm (q2) of chromosome 15 was found. The 15q2 trisomy was due to a chromosome 14, to the long arm of which an extra 15q2 region was attached (14pter----14q32::15q22----15qter). In the second trisomy 15q2 was present as a consequence of a balanced t(7;15)(p22;q15) translocation in the mother.     

Partial trisomy 15q1

Summary A supernumerary extra chromosome of maternal origin, precisely described from QM- and C-banding patterns, was studied in a mentally defective boy with a severe convulsive disorder. This case is considered to represent a specific phenotype of trisomy 15q1. The suggestion that in cases of partial trisomy 15q different phenotypes are due to the second chromosome involved in interchange is supported by the observation of a tertiary trisomy in 2 sibs. It resulted from a balanced reciprocal translocation in the mother t(8q+15q-) and caused an unusual malformation syndrome (mental deficiency, cleft lip and palate, funnel chest, hypospadias).     

Partial trisomy 2q and familial translocation t(2;12)(q31;q24)

Summary Report is given of a boy with trisomy of the distal part of the long arm of chromosome 2 (q31ter) due to a balanced 2/12 translocation in the mother: 46,XX,t(2;12) (q31;q24). Other phenotypically normal carriers of this balanced translocation are the patients sister and grandfather. The patient shows a variety of dysplastic signs mainly of the face.     

A girl with the Prader-Willi Syndrome and Robertsonian translocation 45,XX,t(14;15)(p11;q11) which was present in three normal family members

Summary A 21-year-old girl with classical Prader-Willi Syndrome was found to have a 14;15 Robertsonian translocation—45,XX,t(14;15)(p11;q11). This type of Robertsonian translocation was not found in any patient from 8 surveys covering 6144 patients with mental retardation. Chromosome 15 has been involved in translocations in patients with the Prader-Willi Syndrome with greater than expected frequency. This is the first report of a 14;15 translocation and the Prader-Willi Syndrome. The same balanced translocation was present in the patient's mother and 2 normal siblings. Future genetic counselling for these 2 siblings will be difficult.     

47,XY,+der(11;22)(q23;q12) following balanced translocation t(11;22)(q23;q12)mat

Summary Report of a supernumerary extra chromosome der(11;22)(q23; q12) resulting from a balanced translocation in the mother. The propositus suffers from mental deficiency, deafness and extreme muscular weakness and exhibits cleft palate, a labial lymphangioma and an atrial septum defect. Since the features of partial trisomy 11q23 frequently associated with a translocation t(11q;22q) bear similarities with the cases of so called trisomy 22 one might conjecture that some of these observations are in fact products of translocations including partial 11q.     

46,XX, der(15),t(Y;15)(q12;p11) karyotype in an azoospermic male

We report on a Yq/15p translocation in a 23-year-old infertile male referred for Klinefelter Syndrome testing, who had azoospermia and bilateral small testes. Hormonal studies revealed hypergonadotropic hypogonadism. Conventional cytogenetic procedures giemsa trypsin giemsa (GTG) and high resolution banding (HRB) and molecular cytogenetic techniques Fluorescence In Situ Hybridization (FISH) performed on high-resolution lymphocyte chromosomes revealed the karyotype 46,XX, t(Y;15)(q12;p11). SRY-gene was confirmed to be present by classical Polymerase Chain Reaction (PCR) methods. His father carried de novo derivative chromosome 15 [45,X, t(Y;15)(q12;p11)] and was fertile; the karyotype of the father using G-band technique confirmed a reciprocal balanced translocation between chromosome Y and 15. In the proband, the der (15) has been inherited from the father because the mother had a normal karyotype (46,XX). In the proband, the der (15) could have produced genetic imbalance leading to unbalanced robertson translocation between chromosome Y and 15, which might have resulted in azoospermia and infertility in the proband. The paternal translocation might have lead to formation of imbalanced ova, which might be resulted infertility in the proband. Sister''s karyotypes was normal (46,XX) while his brother was not analyzed.     

Tertiary trisomy of 10p15.pter and 14pter.ql3 due to maternal translocation t(10;14)(p15;q13)

Double partial trisomy resulting from 3:1 segregation of the respective chromosomal segments of the chromosomes involved in a balanced translocation in meiosis is rarely reported in the literature. We present here a first patient with multiple congenital malformations associated with double partial trisomy of 10pter-p15 and 14pter-q13 resulting from 3:1 segregation of maternal balanced translocation t(10;14)(p15;q13). Proximal partial trisomy of chromosome 14 and subterminal trisomy of the short arm of the chromosome 10 are rare. The present case is the first case with double partial trisomy of these segments resulting from 3:1 segregation of a maternal balanced translocation.     

A partial trisomy 15q due to 15;17 translocation detected by conventional cytogenetic and FISH techniques

We report a case having multiple abnormalities including the simultaneous presence of the heart defect and central nerve system abnormalities, which has been reported in a few cases, and with a partial trisomy 15q. Partial trisomy 15q has been inherited from a balanced translocation carried by his phenotypically normal father, detected by traditional banding and fluorescence in situ hybridization (FISH). Application of FISH using whole chromosome specific library probes, locus specific and repetitive probes allowed us to detect the translocation between chromosomes 15q and 17q. Simultaneous application of probes revealed the position of the translocation. Interestingly, in addition to the chromosomes 15 pericentromeric signals, the use of chromosome 15 beta-satellite III probe demonstrated an extra signal on chromosome 14 in both metaphase, and lighted three signals interphase nuclei which was inherited from his father. This patient is compared with other partial trisomy 15q patients reported in the literature. The results are also discussed in relation to genetic counselling for the possible relation of chromosome abnormality and clinical findings.     

Two familial cases with trisomy 15q dist due to a rcp(5;15)(p14;q21)

Summary A trisomy of the distal long arm of chromosome 15 (q21qter) resulting in similar phenotypic and developmental abnormalities in two related children (a boy and a girl) is described. The chromosome defect was due to malsegregation of a balanced translocation (5;15)(p14;q21) in one of the parents. It was inherited in four generations and accompanied by recurrent miscarriages. Comparison of these patients with four previously published cases of trisomy 15q dist reveals a pattern of common features including: microdolichocephaly with characteristic strikingly protuberant occiput and predominance of the visceral over the cerebral cranium; peculiar facial dysmorphism—narrow antimongoloid palpebral fissures; large, malformed, low-set ears; micrognathy; long philtrum; short neck; cardiopathy; profound encephalopathy with lack of suck and swallow reflexes; and no growth retardation.     

A t(X;15)(q23;q25) with Xq reactivation in a lymphoblastoid cell line from Fanconi anemia.

A t(X:15)(q23;q25) was detected during cytogenetic investigation of a lymphoblastoid cell line established from a female patient with Fanconi anemia. The translocation was apparently balanced at passage 300 and unbalanced at passage 13. A chromatid exchange between both the normal and the der(15), between the centromere and band 15q25, may explain these results. Replication studies, following BrdU incorporation, indicate that the segment Xq23----qter from the der(15) is early replicating whereas segment Xpter----q23 from the der(X) is late replicating. Since the normal X was early replicating, it is concluded that the segment of the long arm of chromosome X, separated from its inactivation center by the translocation, was reactivated. This interpretation is confirmed by the methylation patterns of the hypoxanthine phosphoribosyltransferase gene (HPRT), mapped on Xq26, which corresponds to that of an active gene, whereas that of phosphoglycerate kinase (PGK1), which remained on the der(X), corresponds to that of an inactive gene. This is the first example of reactivation of a segment of the X chromosome following a structural rearrangement in somatic cells.     

Partial trisomy for the distal part of the long arm of chromosome 15 due to a balanced maternal X/15 tranlsocation]

Partial trisomy for the distal part of 15q due to a balanced maternal translocation t(X;15) is described in a 21-month old girl with growth and psychomotor retardation and a cranio-facial dysmorphism ressembling that of a previously reported patient. Treatment of lymphocytes with BrdU has shown inactivation of the normal X in the mother, and inactivation of either the abnormal or the normal X in the proposita. When the abnormal X was inactivated, the extent of inactivation of the autosome was variable.     

Unexpected Inheritance of a Balanced Homologous translocation t(22q;22q) from father to a phenotypically normal daughter

Rearrangements between homologous chromosomes are extremely rare and manifest mainly as monosomic or trisomic offsprings. There are remarkably few reports of balanced homologous chromosomal translocation t (22q; 22q) and only two cases of transmission of this balanced homohologous rearrangement from mother to normal daughter are reported. Robersonian translocation carriers in non-homologous chromosomes have the ability to have an unaffected child. However, it is not possible to have an unaffected child in cases with Robersonian translocations in homologous chromosomes. Carriers of homologous chromosome 22 translocations with maternal uniparental disomy do not have any impact on their phenotype. We are presenting a family with a history of multiple first trimester miscarriages and an unexpected inheritance of balanced homologous translocation of chromosome 22 with paternal uniparental disomy. There are no data available regarding the impact of paternal UPD 22 on the phenotype. We claim this to be the first report explaining that paternal UPD 22 does not impact the phenotype.     

The unbalanced offspring of the male carriers of the 11q;22q translocation: nondisjunction at meiosis II in a balanced spermatocyte

Summary Carriers of the standard translocation t(11;22) (q23.3;q11.2) produce only one type of unbalanced offspring, a tertiary trisomy resulting into the karyotype 47,XX or XY, +der(22)t(11;22)(q23.3;q11.2), usually derived from the mother. The exception is one single patient 47,XY,t(11;22)(q23.3;q11.2),+der(22)t(11;22) (q23.3;q11.2)pat. We report a second case with the same karyotype, also of paternal origin. Thus, the rare unbalanced offspring of a carrier father (only 5 cases known) may receive a supernumerary der(22), as a consequence of tertiary trisomy, but also as a consequence of nondisjunction at meiosis II of a balanced spermatocyte.     

Molecular cytogenetic characterization of a familial balanced reciprocal translocation t(11;18) (q13.3; q23) associated with pregnancy wastage

A new male patient associated with a pregnancy wastage was detected in China. Cytogenetic analyses including G-banding, chromosome painting and observation of synaptonemal complexes (SCs) demonstrated that the pregnancy wastage was associated with a balanced reciprocal translocation t(11;18) (q13.3; q23). The proband was the carrier of the translocation and his karyotype was 46,XY,t(11;18)(11pter-->11q13.3:: 18q23-->18qter; 18pter-->18q23::11q13.3-->11qter). The pedigree was analyzed based on a G-banded karyotype of the nine familial members. The translocation chromosomes came from the proband's mother. The result of the SC observation in the proband showed that each of the spermatocytes displayed one quadrivalent during their pachytene stages. In the quadrivalents, there existed homologous and nonhomologous synapses and the latter occurred widely during early, middle and late pachytene stages. The reasons and genetic basis of the pregnancy wastage are discussed.     

Partial trisomy of 13(pter→q12) due to 47,XY,+der(13),t(13;22)(q12;q13)mat

Summary A 36-month-old boy presented with short stature, short neck, shield-shaped chest, and mental retardation. Chromosome analysis showed trisomy for the short arm and the proximal portion of the long arm of chromosome 13 [47,XY,+der(13),t(13;22)(q12;q13)mat]. The patient's mother has a balanced translocation between the long arms of chromosomes 13 and 22 [46,XX,t(13;22)(q12;q13)]. The patient's neutrophils showed an elevated number of nuclear projections and his fetal hemoglobin level was undetectable.     

Translocation (13q21q)

Summary A (13q21q) translocation was found in an infant with Down's syndrome. The 17-year-old mother and the grandmother carried the translocation 45,XX,t(13;21)(p12;q11). The great grandparents had normal karyotypes. Fluorescence marker studies suggested that the translocation originated in the great grandmother. The hypothesis was supported by satellite association studies which showed a significant excess of 13–21 and 13–15 associations in the great grandmother.     

A maternal inherited translocation t(1;22)(q11;p11) in two infertile brothers

We report two infertile brothers presenting with azoospermia and oligozoospermia. Cytogenetic studies using G-banding and FISH analysis on lymphocyte cultures revealed an autosomal balanced reciprocal translocation t(1;22)(q11;p11) in both males. The same translocation was found in their mother, but not in a third fertile brother and maternal uncle suggesting that this translocation might compromise the male but not the female gametogenesis in this family.