Additional chromosome in a child as a result of a balanced reciprocal translocation t(12;18)(p13;q12) in his mother's karyotype

In this case report we present a child with an additional chromosome in the karyotype. The karyotypes of the boy and his parents were analyzed by use of a conventional banding technique (GTG) and fluorescence in situ hybridization (FISH). Probes painting whole chromosomes 12 and 18 were used in FISH. Cytogenetic examination of the parents revealed that his mother was carrying balanced reciprocal translocation between chromosomes 12 and 18. Her karyotype was described as 46,XX,t(12;18)(p13;q12). Father's karyotype was normal, described as 46,XY. The boy's karyotype was defined as 47,XY,+der(18)t(12;18)(p13;q12). The additional chromosome appeared probably due to 3:1 meiotic disjunction of the maternal balanced translocation, known as tertiary trisomy. The mother displayed a normal phenotype and delivered earlier a healthy child. However, the boy with the unbalanced karyotype shows multiple congenital abnormalities.     

Deletion - translocation del (12) (p11) leads to (t10;12) (p13;pII).

Renewed examinatinon with improved banding techniques of a boy previously reported to have the karyotype 46, XY,del(12)(p11) revealed a translocation 46, XY,t(10;12)(p13;p11), and reexamination of a boy previously reported to have the karyotype 46,XY/46,XY,del(5)(p13) showed the same mosaicism, but with a significantly lower frequency of cells with del(5)(p13), 8% compared with 23% at the time of birth. The decrease of the frequency of cells with chromosome abnormality in mixoploids during the first years of life as found in the present case as well as in prevously reported cases is discussed.     

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.     

A t(Y;15) translocation with a deletion of the proximal Yq in a boy with mixed gonadal dysgenesis

Summary A Japanese boy with genital malformation and mixed gonadal dysgenesis is described. The karyotype appeared to be 46,X t(15;Y)(p13;q11). A comparison of the Q-positive segment on der(15) with that of the paternal Y chromosome revealed, however, the loss of over half of the Q-positive segment from the paternal Y during t(15;Y) translocation. The father had an unusually long Y chromosome that corresponded to a chromosome 18. DNA analysis further revealed a deletion of the non-fluorescent part of the long arm of the Y chromosome spanning interval 5–6.     

A Turner patient with a 45,X,t(1;2) (q41;p11.2) karyotype

The most common chromosomal anomaly is 45,X in the Turner syndrome. In addition to this, anomaly, mosaicism such as structural 46,X,i(Xq), 46,X,del(Xp), 46,X,r(X), 46,X,t(X;Y) and numerical 46XO/46,XX/47XXX are seen rather frequently. An infant with the Turner syndrome was found to have a karyotype 45X,t(1;2) (q41;p16) using high resolution banding. Based on our knowledge, we present the first case of 45X,t(1;2) (q41;p11.2), a karyotype in Turner's syndrome in the literature.     

Partial trisomy 14q due to maternal t(4;14)(p16;q32) in a dysmorphic newborn

Partial Trisomy 14q is a rare chromosomal disorder that mostly results from a parental translocation. We report here a newborn boy with partial trisomy 14q and dysmorphic features that are compatible with previously reported cases. Conventional cytogenetic analysis revealed an extra chromosomal segment at the end of the short arm of chromosome 4. In order to determine the origin of this chromosome region we used subtelomeric FISH technique. Based on the results of these cytogenetic studies and the physical examination, this dysmorphic case was diagnosed as partial trisomy of 14q and his karyotype determined as 46 XY, der(4)t(4;14)(p16;q32) resulting from a balanced maternal translocation identified as 46,XX, t(4;14)(p16;q32).     

De novo balanced translocation (2;10)(q24;q22) associated with mental retardation

We report a case of a reciprocal translocation between the long arms of the 2 and 10 chromosomes observed in a 14-year-old male with mild mental impairment, compulsive and obsessive behavior. The apparently balanced translocation was characterized by fluorescence in situ hybridization and the karyotype was 46, XY, t(2;10)(q24;q22). The way by balanced chromosomal translocations can lead to a disease phenotype are reviewed and discussed.     

A severely mental and motor retarded boy with monosomy 9pter-->p22 trisomy 10q26-->qter due to paternal reciprocal translocation 46,XY,t(9;10)(p23;q26)

We report on a twenty-two months old male patient with hypotonia, mental and motor retardation and trigonocephaly. Standard GTG banding chromosomal analysis (from metaphyses of a periferal blood lymphocyte culture) showed 46,XY, der(9) monosomy 9pter-->p22, trisomy 10q26--> qter karyotype. This unbalanced translocation resulted from the father's t(9,10) (p22;p26) karyotype. Deletions of the terminal part of 9p and partial trisomy of chromosome 10q are rare chromosomal disorders. To our knowledge, this is the first case report in the literature of a deletion of 9pter-->p22.3 and a duplication of 10q26-->qter. We assume that the clinical anomalies are due to der(9) monosomy 9pter-->p22, trisomy 10q-->26qter.     

Unbalanced karyotype due to adjacent 1 segregation of t(11;22)(q23.3;q13.2).

The 11q;22q translocations, whatever the breakpoints may be, are of particular interest because of their propensity to 3:1 segregation of the chromosomes at meiosis I. Until now, no unbalanced karyotype resulting from 2:2 adjacent segregation was published among offspring of 11q;22q translocation carriers. The authors report the case of an unbalanced karyotype due to adjacent 1 segregation of a maternal translocation (11;22)(q23.3;q13.2). The proband's karyotype was 46,XX,-22,+der(22)(11;22)(q23.3;q13.2)mat. This finding demonstrates that adjacent 1 segregation is possible in t(11;22) with breakpoints at 11q23 and 22q13, and can lead to birth of viable infants.     

Trisomy 18q: 46,XX,-10,+der(10) t(10;18) (p15;q12) pat: a case report.

A 2-month-old female with intrauterine and postnatal growth retardation, multiple congenital anomalies, absent right kidney, congenital heart disease was investigated. Her karyotype revealed, 46,XX,-10,+der(10), t(10;18) (p15;q12) pat. The child died at 2 months 2 weeks. This is the third case of trisomy 18q resulting from translocation of chromosome 10 and 18.     

A dysmorphic newborn with 45,X,der(1)inv(1)(p13;qter)t(Y;1)(pter-->q11;p13),-Y de novo karyotype

A dysmorphic newborn with 45,x,der(1)inv(1)(p13;qter)t(y;1)(pter-->q11;p13),-Y de novo karyotype: Y/autosome translocations are very rare chromosomal rearrangements. In most cases, the long arm of the Y chromosome is translocated onto an autosome and most patients are referred because of male infertility. Y/1 translocations are very rare, and have been reported in seven patients so far. Pericentric inversions may be seen in all chromosomes and are not associated with phenotypic abnormalities. Here we report a 6-day old male baby with prenatal growth retardation, frontal bossing, hypertelorism, micrognathia, cleft soft palate, absent uvula, hypospadias, simian line in both hands and hammer toes. Cytogenetic analysis was performed with GTG-banding, C-banding and FISH analysis containing X centromeric probe, Yq12-qter locus specific probe and whole chromosome Y probe. An unbalanced Y/1 translocation was diagnosed: 45,X,der(1)inv(1)(p13;qter)t(Y;1)(pter-->q11;p13),-Y.     

Two cases of partial trisomy 10q syndrome due to a familial 10;20 translocation

We describe an eleven day-old boy and his first degree double cousin who both have distal trisomy 10q syndrome. Their cytogenetic analysis using GTG-banding showed an unbalanced translocation 46, XY, -20, +der(20), t(10;20)(q22.3, p11) mat and 46, XX, -20, +der(20), t(10;20)(q22.3, p11) mat. The translocation was confirmed by FISH. We have found balanced translocation t(10;20)(q22.3; p11) with cytogenetic and FISH studies in the mothers and maternal grandfather of these children. Our cases had typical craniofacial and visceral anomalies of this syndrome. However case 1 had an agenesia of corpus callosum which was not previously described and case 2 had hypertrophied cardiomyopathy and cliteromegaly which were previously described as rare anomalies for this syndrome.     

Double partial trisomy of 6p23-pter and 9pter-q21.2 in a neonate resulting from 4:2 meiotic segregation of a maternal complex t(6;7;9)(p23;p15;q21.2) translocation

We report, a newborn presenting multiple congenital abnormalities with karyotype; 47,XY,der(7)t(6;7)(pter-p23::p15-->qter),+der(9)t(7;9)(pter-->p15::q21.2--> pter)t(6;7;9)(p23;p15;q21.2)mat[20]. The mother and her phenotypically normal daughter were carriers of a complex chromosomal rearrangement with karyotypes; 46,XX,t(6;7;9)(p23;p15;q21.2)[20]. Paternal chromosomes were normal. In our case the extra derivative chromosome was the result of a 4:2 segregation of the chromosomes involved in translocation during oogenesis. Double partial trisomy in newborns resulting from 4:2 segregation is a rare event, and double partial trisomies of the 6p23-pter and trisomy 9pter-q22 regions have not reported to date.     

Partial trisomy 4q and monosomy 9p resulting from a familial translocation t(4;9)(q27;p24) in a child with choanal atresia.

A male infant with a deletion of 9p and concomitant duplication of 4q: 46,XY, der(9)t(4;9)(q27;p24), is described. Parental chromosome analysis showed a balanced maternal translocation. To our knowledge, the above cytogenetic and clinical abnormalities have not been described previously. A phenotype comparison is presented with previously reported cases concerning a deletion of 9p and a duplication of 4q.     

Sex reversal due to Xp disomy by t(X;Y)(p21;q11).

A 20-month-old infant exhibiting psychomotor retardation, dysmorphisms and ambiguous external genitalia was found to have a 46-chromosome karyotype including a normal X chromosome and a marker Y with most of Yq being replaced by an extra Xp21-->pter segment. The paternal karyotype (G and C bands) was 46,XY. The marker Y composition was verified by means of FISH with a chromosome X painting, an alphoid repeat and a DMD probe. Thus, the final diagnosis was 46,X,der(Y)t(X;Y)(p21;q11)de novo.ish der(Y)(wcpX+,DYZ3+,DMD+). The patient's phenotype is consistent with the spectrum documented in 13 patients with similar Xp duplications in whom sex reversal with female or ambiguous genitalia has occurred in spite of an intact Yp or SRY gene. A review of t(X;Y) identifies five distinct exchanges described two or more times: t(X;Y)(p21;q11), t(X;Y)(p22;p11), t(X;Y)(p22;q11-12), t(X;Y) (q22;q12), and t(X;Y)(q28;q12). These translocations probably result from a recombination secondary to DNA homologies within misaligned sex chromosomes in the paternal germline with the derivatives segregating at anaphase I.     

Pure partial trisomy 5q33-->5q35 resulting from the adjacent-1 segregation of a paternal (5;14)(q33;p12) translocation.

A 14-year-old male was referred for evaluation of mental retardation with short stature and dysmorphic features. His karyotype was 46,XY,der(14)t(5;14)(q33;p12)pat, resulting in a pure partial 5q33-q35 trisomy due to the adjacent-1 segregation of a paternal balanced translocation. Paternal blood karyotype revealed a balanced translocation t(5;14)(q33;p12) retaining Ag-Nors. To date, only two cases of pure partial 5q trisomies spanning this region have been reported. Analysis of these cases and the one we report does not allow the delineation of a specific phenotype.     

Analysis of segregation and aneuploidy in two reciprocal translocation carriers, t(3;9)(q26.2;q32) and t(3;9)(p25;q32), by triple-color fluorescence in situ hybridization

Meiotic segregation patterns of chromosomes 3 and 9 were analyzed in sperm of two translocation carriers (t(3;9)(q26.2;q32) and t(3;9)(p25;q32)) by triple-color fluorescent in situ hybridization (FISH) with a telomeric DNA probe in addition to two centromeric probes. The frequencies of each sperm product resulting from alternate or adjacent I, adjacent II and 3:1 segregation in a t(3;9)(q26.2;q32) translocation carrier were 88.35%, 5.44% and 5.94%, respectively. On the other hand, the frequencies of each sperm product in a t(3;9)(p25;q32) translocation carrier were 89.23%, 6.02% and 4.48%, respectively. Of all the sperm products, the frequency of normal or chromosomally balanced sperm in a t(3;9)(q26.2;q32) and a t(3;9)(p25;q32) were 52.49% and 47.25%, respectively. The frequencies of each sperm product resulting from various segregations were different between both carriers and significantly deviated from the expected frequencies. Additional dual-color and triple-color FISH were performed to analyze aneuploidy rates for chromosomes 12, 17, 18, X and Y in order to detect any interchromosomal effect; no evidence of an interchromosomal effect was found.     

Meiotic segregation analysis by FISH investigation of spermatozoa of a 46,Y,der(X),t(X;Y)(qter-->p22::q11-->qter) carrier

Chromosome analysis performed on a 30-year-old man revealed a 46,Y,der(X),t(X;Y)(qter-->p22::q11-->qter) karyotype, confirmed by fluorescence in situ hybridization (FISH). The man was of short stature, and no mental retardation was noticed; genitalia and testes were normal, as were the patient's FSH, LH, and testosterone blood levels. Sperm analysis showed azoospermia at the time of the first sampling and severe oligozoospermia, with 125,000 spermatozoa/milliliter, at the time of the second sampling. The sperm gonosomal complement of this patient and of a 46,XY donor were analyzed using multicolor FISH with X- and Y-chromosome probes. Our results clearly indicated that germinal cells carrying the translocation are able to complete the meiotic process by producing spermatozoa compatible with normal embryonic development, with more than 80% of the spermatozoa having either a Y chromosome or a der(X); however, a high level of spermatozoa with gonosomal disomies was observed. We also found a significant increase in the frequency of autosomal disomies in the carrier, which would suggest an interchromosomal effect. All previously reported cases in adult males were associated with azoospermia; testicular histological studies, performed in patients carrying the same X;Y translocation, showed spermatogenetic arrest after pachytene. To our knowledge, this is the first molecular analysis of the gonosomal complement in spermatozoa of men with a t(X;Y)(qter-->p22::q11-->qter).     

Mosaic 13 trisomy due to de novo 13/13 translocation with subsequent fission karyotype: 46,XX,-13,+t(13;13)(p11;q11)/46,XX,del(13)(p11)

Summary A severely retarded child with multiple malformations was found to present a mosaic karyotype 46,XX,-13,+t(13;13)(p11;q11)/46,XX,del (13)(p11), which probably originated as the result of a de novo 13/13 translocation in a parental gamete, followed by postzygotic fission of the translocation chromosomse.     

Holoprosencephaly in a fetus with a 46,XX,der(7), t(7;8)(q36.1;p12) mat karyotype

In this report we present a female fetus with hemilobar holoprosencephaly and 46,XX,der(7)t(7;8)(q36.1;p12) mat karyotype. The holoprosencephaly-sequence is apparently related with the distal 7(q36.1----qter) deficiency.