Segregation of a paternal insertional translocation results in partial 4q monosomy or 4q trisomy in two siblings

A genetics evaluation was requested for a 6-week-old infant with multiple congenital malformations including mild craniofacial anomalies, truncal hypotonia, hypospadias, and a ventriculoseptal defect. Blood obtained for chromosome analysis revealed an abnormal chromosome 4. Paternal chromosome analysis showed a 46,XY, inv ins (3;4) (p21.32; q25q21.2), inv(4)(p15.3q21.2) karyotype. Therefore, the proband's chromosome 4 was the unbalanced product of this insertional translocation from the father resulting in partial monosomy 4q. Additionally, the derivative 4 had a pericentric inversion which was also seen in the father's chromosome 4. During genetic counseling, the proband's 2-year-old brother was evaluated. He was not felt to be abnormal in appearance, but was described as having impulsive behavior. Chromosome analysis on this child revealed 46,XY,der(3)inv ins(3;4)(p21.32;q25q21.2)pat. This karyotype results in partial trisomy 4q. FISH using two-color “painting” probes for chromosomes 3 and 4 confirmed the G-banded interpretation in this family. The segregation seen in this family resulted in both reciprocal products being observed in the two children, with partial 4q monosomy showing multiple congenital anomalies, and partial 4q trisomy showing very few phenotypic abnormalities. © 1995 Wiley-Liss, Inc.     

Partial duplication of the long arm of chromosome 6: a clinically recognisable syndrome.

Reciprocal translocations involving the short arm of acrocentric chromosomes can segregate to produce partial duplications without associated deletions. We present a case of an infant with a 46,XY,-15,+der(15),T(6;15)(q23;p12)pat chromosome complement. The infant had multiple congenital abnormalities including cranial anomalies, facial dysmorphism, anterior webbing of the neck, cardiac anomalies, and joint contractures. From a comparison of the infant's phenotype with 20 other patients with a similar duplication, it is evident that partial duplication of the long arm of chromosome 6 is a clinically diagnosable syndrome.     

Familial partial monosomy 5p and trisomy 5q; three cases due to paternal pericentric inversion 5 (p151q333)

A family is described in which the mother's 9 pregnancies ended in the birth of 2 healthy girls, 4 spontaneous abortions and 3 infants with multiple congenital malformations as bird-headed appearance, pre- and postnatal growth deficiency, microcephaly, micrognathia with small mouth and cat-like cry. Two of the three affected sibs had complex cardiac malformations incompatible with life; the third had a bicuspid aortic valve. Chromosomal investigation revealed an abnormal karyotype: 46,XX,rec(5),dupq,inv(5)(p151q333)pat, leading to a partial monosomy 5p and partial trisomy 5q. A large pericentric inversion of chromosome 5 was found in the father: 46,XY,inv(5)(p151q333) as well as in the firstborn healthy female sib. The clinical features partly fit the partial monosomy 5p as well as the partial trisomy 5q syndrome.     

Cri du chat syndrome due to meiotic recombination in a pericentric inversion 5 carrier

A female infant presented at birth with hypotonia, growth retardation, distinctive facies, multiple congenital anomalies, and a high-pitched mewing cry characteristic of cri du chat syndrome. Chromosome studies from both peripheral blood and fibroblasts showed a 46,XX,5p- karyotype. Parental chromosome studies revealed that the mother carried an apparently balanced pericentric inversion of one chromosome no. 5, 46,XX,inv(5)(p14q35). Meiotic crossing-over in the mother within the inverted segment of chromosome 5 gave rise to the unbalanced karyotype, 46,XX,rec(5)dup q, inv(5)(p14q35)mat in the infant. A small terminal segment of the long arm of chromosome 5 (q35-pter) is duplicated with a deletion of the short arm of chromosome 5 (p14-pter), accounting for the features of cri du chat syndrome. Fewer than 1 in 200 of cri du chat syndrome cases are due to recombination aneusomy arising from a parental inversion of chromosome 5. Some of these cases, however, do not have typical cri du chat syndrome, reflecting significant duplication of 5q material. These cases are reviewed with the present case, and recombination behaviour leading to chromosome imbalance is discussed.     

Chromosomal anomaly of 6q in chronic myelogenous leukemia (CML)

Anomalies of chromosome 6q, along with other chromosomal anomalies, are described in the bone marrow cells of two patients with chronic myelogenous leukemia (CML). One patient, a 14-year-old male, developed the karyotype 46,XY,t(1;6)(p36;q15),del(3)(q25),del(17)(p11),? inv(17)(q12q24) during blastic crisis of his disease. The other patient, a 24-year-old male, had the karyotype 46,XY,del(6)(q13),t(9;22)(q34;q11) during the early phase of his disease and evolution of i(17q) in the karyotype late in the disease.     

Trisomy 18q: 46, XX,13q+,t(13;18)(q32;q11) in a newborn associated with multiple congenital anomalies due to paternal reciprocal translocation, 46, XY,-13,+der(13)/t(13;18)(q32;q11)

A 20-day-old female neonate presented with multiple congenital anomalies, convulsions and failure to thrive. Karyotype analysis of the proposita revealed an unbalanced translocation, 46, XX,13q+,t(13;18)(q32;qll)pat resulting in partial trisomy 18q. Her father and a 5-year-old sister were phenotypically normal, balanced translocation carriers, 46, XY, -13, + der(13),t(13;18)(q32;qll) and 46, XX,-13,+der(13),t(13;18)(q32;qll), respectively. The case presented here is the second liveborn reported with trisomy 18q and is of interest from the point of view of the structural chromosomal aberration resulting in the manifestations of most features of trisomy 18 and some of 13q monosomy. The infant died due to convulsions at the age of 2 months.     

Partial trisomy 19p: case report and natural history

Partial trisomy 19p was noted in an infant delivered at 39 weeks gestation with intrauterine growth retardation (IUGR), bilateral club feet, renal abnormalities, hearing deficit, and multiple dysmorphic features. Chromosomes obtained following amniocentesis at 32 weeks gestation revealed that the fetus was partially trisomic for 19p and partially monosomic for a portion of the terminal band of 3q, having inherited a derivative chromosome 3 from her father [46,XX,-3,+der(3)t(3;19)(q29;p13.2)pat]. The father was found to be the carrier of a balanced translocation between chromosomes 3 and 19 [46,XY,t(3;19)(q29;p13.2)]. The only other case of partial trisomy 19p previously reported was an infant with partial trisomy 19p and partial monosomy 13q who died at 59 days of age. This report by Byrne et al. [(Am J Hum Genet 1980: 32:64A] is similar to our case with respect to IUGR, small palpebral fissures, and ear anomalies.     

Familial reciprocal translocation, t(2;10)(p24;q26), resulting in duplication 2p and deletion 10q

We describe a familial reciprocal translocation between the distal part of the short arm of chromosome 2 and the long arm of chromosome 10. Five individuals in two generations had multiple congenital anomalies. Their karyotypes were 46, XX or XY,−10, + der(10), t(2;10)(p24;q26). Seven persons were balanced translocation carriers whose karyotypes were 46, XX or XY, t(2;10)(p24;q26). Common manifestations included mental retardation, strabismus, narrow high-arched palate, wide alveolar ridges, other facial abnormalities, genital abnormalities and mutism. The phenotype of the unbalanced individuals is compared to that of previously published cases of the syndrome of partial duplication 2p and to reported patients with partial deletion of 10q.     

Distal 5q deletion syndrome: phenotypic correlations

We describe the phenotypes of two male sibs with partial monosomy of chromosome 5 [46,XY,der(5)inv ins(1;5)(p32;q35.4q34)]; maternally derived from a balanced insertion of 1 and 5 [inv ins (1;5)(p.32;q35.4q34)]. One sib had microcephaly, cleft lip and palate, facial anomalies, atrial (ASD) and ventricular (VSD) septal defects, camptodactyly 4th and 5th fingers, and developmental delay. The other sib showed microcephaly, facial anomalies, ASD, hypotonia, primary optic nerve hypoplasia, and developmental delay. Only seven other patients with 5q deletions distal to 5q33 have been reported and none showed the putative breakpoints identified in our two patients. All nine showed developmental delay or malformations of the CNS and facial anomalies; six of nine had defects of cardiac septation. Our two patients and one other were shown to have only one copy of the cardiac specific hCSX gene that defines in part the etiology of their ASD and VSD. The other components of their phenotypes cannot be related at present to genes identified in the deleted segments.     

Partial trisomy 12q: clinical and cytogenetic observations

High resolution chromosome banding showed a male infant with profound mental retardation, hypertonia and multiple congenital anomalies to have the karyotype 46,XY,-der (2),t(2;12)(q37.3;q24.13)pat. Most of the clinical findings were compatible with those of the previously described cases with partial trisomy 12q. Some of the clinical features seem to disappear with increasing age.     

Trisomy 1q24----1q41 in two sibs with an insertion in an inverted chromosome 4.

We report two patients whose karyotype revealed an additional segment 1q inserted into an inverted chromosome 4. The patients were partially trisomic for the region 1q24----1q41, karyotype 46,XY or XX, inv ins(4;1)inv(4)(q28;q24q41)(p15 . 3q28), while in the mother the chromosomal aberration was balanced. The inserted segment was inverted. In six patients from three other families with insertions, the segment 1q25----1q32 was inserted into the short arm of chromosome 1. In another patient, the segment 1q25----1q42 of the mother was inverted and inserted into the long arm of chromosome 6. These findings suggest an increased susceptibility for a segment of the long arm of chromosome 1 to be inserted and inverted in rearrangements.     

Abnormal chromosome 9 in a neonate program. Report of three cases

We describe three cases with abnormal chromosome 9. Patient 1 shows translocation in a homologous chromosome, with a karyotype of 46,XX,t(9;9)(9pter----cen----9pter; 9qter----cen::9q13----9qter), 1qh+. This case has a variety of anomalies, including brain anomalies. Patient 2 shows a partial trisomy 9p with a karyotype of 47,XY,+del(9)(pter----q11:). The patient has the typical clinical features of 9p trisomy syndrome. Patient 3 is unique because of partial 9p tetrasomy mosaicism without phenotypic abnormalities; the karyotype is mos 46,XY/47,XY,+dic(9)(pter----cen----q21::q21----cen----pter).     

De novo reciprocal 1p;2q translocation in a child with multiple congenital anomalies/mental retardation syndrome

A newborn male infant was found to have an unusual pattern of congenital anomalies associated with an apparently balanced de novo reciprocal translocation: 46,XY,t(1;2)(p22;q22). The infant had a previously apparently undescribed multiple congenital anomalies and mental retardation syndrome.     

Craniosynostosis associated with partial duplication of 15q and deletion of 2q.

We report on an infant with multiple congenital anomalies including complex craniosynostosis associated with an unbalanced karyotype, 46,XY,-2,+der(2),t(2;15)(q37;q26)pat. The previous report of a child with cloverleaf skull and partial duplication of 15q25----qter and the Man-on-Mouse Homology map suggests that a critical segment for synostosis of sutures may be in this region.     

Partial monosomy 5p and partial trisomy 5q due to paternal pericentric inversion 5(p15.1q35.1)

A male infant with karyotype 46,XY,rec(5),dup q,inv(5)(p15.1 q35.1)pat is presented. The proband showed growth and developmental retardation, complex cardiovascular abnormalities, inguinal hernia and microcephaly in addition to facial appearance and cat-like cry characteristic of the cri-du-chat syndrome. Growth and developmental retardation, and microcephaly noted in this patient were markedly more serious than those observed in patients either with partial monosomy 5p or with partial trisomy 5q alone.     

Jacobsen Syndrome and Beckwith-Wiedemann Syndrome Caused by a Parental Pericentric Inversion inv(11)(p15q24)

Here we report on a male infant presenting the typical pattern of Jacobsen syndrome including trigonocephaly, thrombocytopenia, congenital heart defect, urethral stenosis, and partial agenesis of the corpus callosum. Conventional karyotyping, FISH, SKY and CGH analyses showed that the region distal to the MLL locus on 11q23 was lost and replaced by the distal region of 11p, leading to a partial trisomy of 11p and a partial monosomy of 11q. According to ISCN (1995) the karyotype can be described as 46,XY,add(11)(q2?3). ish 11ptel(D11S2071x3),11qtel(VIJyRM2072x1). Array‐CGH analysis allowed us to narrow down the breakpoints to 11p15.1 and 11q24.1. Methylation analyses of genes located on 11p showed an increased level of the non‐methylated paternal allele of the KCNQ1OT1 gene, confirming the concomitant presence of Beckwith‐Wiedemann syndrome (BWS). The phenotype resulting from the 11q deletion seems to dominate the phenotype due to the distal 11p trisomy. Investigation of the parents revealed that this chromosomal rearrangement was caused by a paternal pericentric inversion inv(11)(p15q24). Since chromosomal aberrations like the one described here can easily be overlooked during routine chromosome analysis, combined FISH analysis using subtelomeric and possibly additional probes should be applied if there is any doubt about the integrity of telomeric regions.     

Novel isodicentric chromosome 18 in an abnormal infant with a mosaic karyotype [46, XY/46,XY, –18,+ dic(18)(q12.2)]

A previously unreported isodicentric chromosome 18 was discovered in an abnormal infant boy whose mosaic karyotype was 46, XY/46,XY,–18, + idic(18)(q12.2). His constellation of congenital anomalies was typical of the 18q-syndrome. The clinical and cytogentic characteristics of this patient are reported, and the literature concerning isochromosomes of 18 is reviewed.     

Novel isodicentric chromosome 18 in an abnormal infant with a mosaic karyotype [46,XY/46,XY,-18,+dic(18)(q12.2])

A previously unreported isodicentric chromosome 18 was discovered in an abnormal infant boy whose mosaic karyotype was 46,XY/46,XY,-18,+idic(18)(q12.2). His constellation of congenital anomalies was typical of the 18q-syndrome. The clinical and cytogenetic characteristics of this patient are reported, and the literature concerning isochromosomes of 18 is reviewed.     

Maternal balanced translocation leading to partial duplication of 4q and partial deletion of 1p in a son: Cytogenetic and FISH studies using band-specific painting probes generated by chromosome microdissection

A 9-month-old boy with pre- and post-natal growth retardation, microcephaly, plagiocephaly, and several minor anomalies had the initial karyotype: 46,XY,der(1)t(1;?)(p36.1;?). Further analysis showed that the der(1) was derived from an unfavorable segregation of a maternal complex chromosome rearrangement, i.e., 46,XX,der(1)t(1;?)(p36.1;?), der(4)t(4;?)(q?;?). Whole chromosome fluorescence in situ hybridization (FISH) and chromosome microdissection were used to clarify the maternal karyotype as: 46,XX,der(1)t(1;4)(4qter→4q33::1p36.13→1qter),der(4)t(1;4)inv(4)(4pter→ 4q31.3::1p36.33→1p36.13::4q33→4q31.3::1p36.33→1pter). Therefore, the karyotype of the boy actually was 46,XY,der(1)t(1;4)(p36.13;q33). Clinical comparison of the patient's clinical findings showed similarities to individuals with partial del(1p) and dup(4q). To our knowledge the above cytogenetic abnormalities have not been described previously. This case further demonstrates the advantages of chromosome microdissection and FISH in the identification of anomalous chromosome regions and breakpoints. Am. J. Med. Genet. 71:160–166, 1997. © 1997 Wiley-Liss, Inc.     

Three rearrangements of chromosome 5 in a patient with myelodysplastic syndrome: an atypical deletion 5q, a complex intrachromosomal rearrangement of chromosome 5, and a paracentric inversion of chromosome 5

We report the case of a 74-year-old man who sought care for de novo myelodysplastic syndrome (RAEB-1). Conventional cytogenetic techniques showed a karyotype with two different deletions of the long arm of chromosome 5 distributed in three clones: 46,XY,del(1)(p34),del(5)(q14q23)[2]/46,XY,del(1)(p34),del(5)(q14q34)[10]/46,idem,inv(5)(q?11q?34)[7]. Precise characterization of the breakpoints, delineation of the deleted regions, identification of the complex intrachromosomal rearrangement of chromosome 5, and sequential accumulation of chromosomal abnormalities were elucidated by several fluorescence in situ hybridization analyses. We also assessed the clinical, biological, and cytogenetic evolution under lenalidomide treatment and after its interruption.