Girl with monosomy 1p36 and Angelman syndrome due to unbalanced der(1) transmission of a maternal translocation t(1;15)(p36.3;q13.1)

We report on a girl with monosomy 1p36.3 and Angelman syndrome due to an unbalanced transmission of a maternal balanced chromosomal translocation. She manifested monosomy 1p36 and Angelman syndrome including generalized hypopigmentation, ataxic movements, intractable seizures with characteristic electroencephalographic (EEG) abnormality compatible with Angelman syndrome, and other minor anomalies, large anterior fontanelle, severe psychomotor retardation, and seizures due to monosomy 1p36. Her karyotype was 45, XX, der(1) t(1;15)(p36.31;q13.1),-15, derived from maternal translocation. Molecular analysis determined a breakpoint of 1p between D1S243 and D1S468, which suggested that most genes contributing to the common phenotype are in the distal region.     

A case of presumptive monosomy 21 re-diagnosed as unbalanced t(5p;21q) by FISH and review of literature

By using fluorescence in situ hybridization (FISH), we demonstrate a case of monosomy 21 to result from an unbalanced translocation involving the short arm of chromosome 5 and the long arm of chromosome 21. Our case is compared to 3 similar cases of t(5p;21q) reported recently, which were also originally diagnosed as monosomy 21. The breakpoint on chromosome 5 in these cases occurred in the p13–p15 region, whereas the breakpoint on chromosome 21 was in the q21–q22 region. Comparison of the clinical findings in these patients demonstrated great similarities. Furthermore, a strong correlation between the clinical manifestations of these patients with cridu-chat syndrome patients was also noted. We suggest that cases with unbalanced t(5p;21q) represent a distinct syndrome which can be grouped under a new category of “5p/21q deletion syndrome.” Am. J. Med. Genet. 70:174–178, 1997. © 1997 Wiley-Liss, Inc.     

Two cousins with partial trisomy 12q and monosomy 12p recombinants of a familial pericentric inversion of the chromosome 12

Partial trisomy 12q and monosomy 12p lead to multiple malformation syndromes. Instead of trisomy 12q that has been reported as a clinically identifiable syndrome, monosomy 12p is characterized by a wide phenotypic spectrum. We report two cousins suffering from severe mental retardation, seizures, and dysmorphic features related to a trisomy 12q24.3-->qter and a monosomy 12p13-->pter resulting from a familial pericentric inversion of chromosome 12. In an attempt to improve the clinical delineation of these two syndromes, we compared our two patients with previous reports of these aneusomies. This review emphasizes the high frequency of familial translocations, including a breakpoint at 12q24 involved in trisomy 12q whereas monosomy 12p occurs most frequently de novo. Despite the poor specificity of the signs, this comparison allowed us to determine the clinical features present in more than 20% of patients with trisomy 12q or monosomy 12p. We particularly emphasize some consistent leading features of monosomy 12p, including microcephaly, dental, cardio-vascular, extremity, and sensorial abnormalities, initially not reported as recurrent in this syndrome.     

Combined partial trisomy 11q and partial monosomy 10p in a 19-year-old female patient: phenotypic and genotypic findings

Constitutional partial trisomy 11q in man mostly occurs in combination with partial trisomy 22 due to a balanced parental translocation t(11;22). Occasionally a chromosome other than 22 is involved in the parental translocation with chromosome 11, resulting in partial monosomy for the other participating chromosome. We report of a patient with partial trisomy 11q and partial monosomy 10p [46,XX,der(10)t(10;11)(p15;q22)] due to a paternal balanced translocation [46,XY,t(10;11)(p15;q22)]. Array CGH showed heterozygosity for a deletion of ～3.46 Mb at 10p15.3p15.2 and gain of ～32.21 Mb at 11q22.2q25. The patient, a 19‐year‐old woman, has a multiple congenital anomaly syndrome with severe developmental and growth delay, muscular hypotonia, iris coloboma, abnormal external ears, widely spaced nipples, atrial septum defect, clubfoot, and arthrogryposis multiplex congenita. Despite multiple health problems and numerous hospitalizations due to massive seizures, pulmonary insufficiency and recurrent infections the patient reached adulthood. The clinical features in our patient are compared to other cases reported in the literature of either partial monosomy 10p or partial trisomy 11q. To the best of our knowledge, this is the first report of the combination of partial trisomy 11q and partial monosomy 10p. Comparing the molecular karyotype and the phenotype of our patient to other patients, the clinical features of our patient are more likely due to partial trisomy 11q than to partial monosomy 10p. © 2011 Wiley Periodicals, Inc.     

De novo (15;21) unbalanced translocation of paternal origin in a girl with Prader-Willi syndrome

We describe a 3-month-old girl with Prader-Willi syndrome and a de novo unbalanced karyotype 45,XX,t(15;21)(q13;q22.3). This rearrangement, resulting in monosomy for the pericentromeric region of chromosome 15 and a virtual monosomy for the 21q distal band, had a paternal origin as demonstrated by Q and NOR staining.     

Variable behavioural phenotypes of patients with monosomies of 15q26 and a review of 16 cases

Patients with trisomy or tetrasomy of distal 15q show a recognizable overgrowth syndrome, whereas patients with a monosomy of 15q26 share some degree of pre- and postnatal growth retardation, but differ with respect to facial and skeletal dysmorphisms, congenital heart disease and intellectual development. By reviewing 16 cases with losses of 15q26 we found that the size of the deletion was also not a predictor of the breadth of the phenotypic spectrum, the severity of disease or prognosis of the patient. Although monosomies of 15q26 do not represent a classical contiguous gene syndrome, a few candidate genes for selected features such as proportional growth retardation and cardiac abnormalities have been identified. In 11 out of 16 patients with monosomy of distal 15q variable neurobehavioral phenotypes, including learning difficulties, seizures, attention-deficit-hyperactivity disorder, hearing loss and autism, have been found. We discuss clinical ramifications for cases with a loss of 15q26 detected by prenatal array-CGH.     

A familial pericentric inversion of chromosome 22 with a recombinant subject illustrating a ''pure'' partial monosomy syndrome.

A family in which a pericentric inversion of chromosome 22, inv(22)(p11q12), is segregating is described. Special reference is made to a unique recombinant subject with a 'pure' partial monosomy 22 syndrome of maternal origin. An attempt has been made to correlate the phenotypic abnormalities with monosomy for the segment 22q12----qter.     

Features of di George syndrome in a child with 45,XX,-3,-22,+der(3),t(3;22)(p25;q11).

A child with an unbalanced translocation resulting in monosomy for chromosomes 22 (q11----pter) and 3(p25----pter) is described. Although no immunological dysfunction could be demonstrated, the abnormalities found are similar to those seen in the di George syndrome which has been associated with monosomy for the same region of chromosome 22.     

t(15;21)(q15;q22.1)pat resulting in partial trisomy and partial monosomy of chromosomes 15 and 21 in two offspring

Two sibs, carriers of unbalanced products of the translocation t(15;21)(q15;q22.1)pat, are described. The sister had Prader-Willi syndrome due to deletion 15 (pter > q15) and partial trisomy 21 (pter > q22.1); her brother had partial trisomy 15 (pter > q15) and partial monosomy 21 (pter > q22.1). The translocation breakpoint on chromosome 21 was located proximal to the SOD1 gene, within a region of 4.0 cM (2.3 Mb) between the loci D21S217 and D21S213. The correlations between the clinical presentation and the molecular findings of the two sibs are discussed in relation to other patients with partial trisomy and monosomy 21. © 1996 Wiley-Liss, Inc.     

Unbalanced translocation (3;5)(q26.1;p14): a clinical report

A patient with a multiple congenital anomalies/mental retardation (MCA/MR) syndrome had an unbalanced translocation (3;5)(q26.1;p14), causing partial 5p monosomy and partial 3q trisomy. The phenotype observed in this patient results from the combination of those described in the isolated dup(3q) and del(5p) syndromes. Some clinical features of this patient are shared by the Smith-Lemli-Opitz syndrome (SLOS), a well-known MCA/MR syndrome due to the deficiency of 7-dehydrocholesterol reductase (DHCR7). We review the previously reported cases of chromosomal anomalies with clinical features suggesting SLOS.     

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.     

Prader-Willi syndrome resulting from an unbalanced translocation: characterization by array comparative genomic hybridization

Prader-Willi syndrome (PWS) is caused by lack of expression of paternally inherited genes on chromosome 15q11-->15q13. Most cases result from microdeletions in proximal chromosome 15q. The remainder results from maternal uniparental disomy of chromosome 15, imprinting center defects, and rarely from balanced or unbalanced chromosome rearrangements involving chromosome 15. We report a patient with multiple congenital anomalies, including craniofacial dysmorphology, microcephaly, bilateral cryptorchidism, and developmental delay. Cytogenetic analysis showed a de novo 45,XY,der(5)t(5;15)(p15.2;q13), -15 karyotype. In effect, the proband had monosomies of 5p15.2-->pter and 15pter-->15q13. Methylation polymerase chain reaction analysis of the promoter region of the SNRPN gene showed only the maternal allele, consistent with the PWS phenotype. The proband's expanded phenotype was similar to other patients who have PWS as a result of unbalanced translocations and likely reflects the contribution of the associated monosomy. Array comparative genomic hybridization (array CGH) confirmed deletions of both distal 5p and proximal 15q and provided more accurate information as to the size of the deletions and the molecular breakpoints. This case illustrates the utility of array CGH in characterizing complex constitutional structural chromosome abnormalities at the molecular level.     

De novo t(4;5) (q3100; q2200) with del(5)(q1500q2200). Tentative delineation of a 5q monosomy syndrome and assignment of the critical segment

An 8-month-old boy with multiple malformations and psychomotor retardation was found to have a de novo t(4;5)(q1300;q2200) with del(5)(q1500q2200). The phenotypical comparison with 10 similar monosomic cases from the literature led us to tentatively delineate a 5q monosomy syndrome and to postulate the band 5q15 as the correspondent critical segment.     

Partial duplication of the long arm of chromosome 15: confirmation of a causative role in craniosynostosis and definition of a 15q25-qter trisomy syndrome

A syndrome of mental retardation and multiple congenital anomalies, including craniosynostosis and overgrowth, was observed in two related individuals from a large kindred. Both of them carried a 15q25.1-qter trisomy associated with a subtle 13qter monosomy resulting from unbalanced segregation of a familial t(13;15)(q34;q25.1) translocation. Reportedly, a further individual in this kindred has the same condition. The present report confirms previous claims that gene(s) in the distal 15q region play a role in suture formation. At the same time it adds new data to the delineation of a 15q25-qter trisomy syndrome.     

Monosomy 7p in meningiomas: a rare constituent of tumor progression

We present karyotypes of 15 meningiomas with structural aberrations of chromosome 7, which were taken from a consecutive series of 400 cytogenetically characterized meningiomas. Twelve of these tumors (80%) displayed partial or complete monosomy 7p with a consensus deleted region of 7p12 approximately pter, in 6 of 15 cases arising from an unbalanced whole-arm t(1;7)(q11;p11), and in 4 of 15 cases from a whole-arm translocation involving other chromosomes. Other types of partial aneusomy 7 (3/15 cases) or balanced aberrations of chromosome 7 (2/15 cases) were relatively rare. In most cases (11/15), the centromeric region of chromosome 7 was involved in the rearrangements. We conclude that in meningiomas, the near-centromeric region of chromosome 7 is particularly prone to structural rearrangements most frequently resulting in monosomy 7p. The investigation of the histopathologic features of this rare cytogenetic subgroup of meningiomas showed no clear genotype/phenotype correlation. As 7 of 11 of the meningiomas with monosomy 7p belonged to World Health Organization grades II or III, which usually comprise less than 20% of all meningiomas, partial loss of 7p appears to be involved in tumor progression in meningiomas. Because monosomy 7p is typically associated with the strongly progression-associated monosomy 1p, however, monosomy 7p represents a cofactor more than a stand-alone feature of meningioma progression.     

Array-based comparative genomic hybridization facilitates identification of breakpoints of a novel der(1)t(1;18)(p36.3;q23)dn in a child presenting with mental retardation

Monosomy of distal 1p36 represents the most common terminal deletion in humans and results in one of the most frequently diagnosed mental retardation syndromes. This deletion is considered a contiguous gene deletion syndrome, and has been shown to vary in deletion sizes that contribute to the spectrum of phenotypic anomalies seen in patients with monosomy 1p36. We report on an 8-year-old female with characteristics of the monosomy 1p36 syndrome who demonstrated a novel der(1)t(1;18)(p36.3;q23). Initial G-banded karyotype analysis revealed a deleted chromosome 1, with a breakpoint within 1p36.3. Subsequent FISH and array-based comparative genomic hybridization not only confirmed and partially characterized the deletion of chromosome 1p36.3, but also uncovered distal trisomy for 18q23. In this patient, the duplicated 18q23 is translocated onto the deleted 1p36.3 region, suggesting telomere capture. Molecular characterization of this novel der(1)t(1;18)(p36.3;q23), guided by our clinical array-comparative genomic hybridization, demonstrated a 3.2 Mb terminal deletion of chromosome 1p36.3 and a 200 kb duplication of 18q23 onto the deleted 1p36.3, presumably stabilizing the deleted chromosome 1. DNA sequence analysis around the breakpoints demonstrated no homology, and therefore this telomere capture of distal 18q is apparently the result of a non-homologous recombination. Partial trisomy for 18q23 has not been previously reported. The importance of mapping the breakpoints of all balanced and unbalanced translocations found in the clinical laboratory, when phenotypic abnormalities are found, is discussed.     

Recurrent unbalanced whole-arm t(1;10)(q10;p10) in myelodysplastic syndrome: a case report and literature review

We report a patient with myelodysplastic syndrome (refractory anemia) showing the karyotype 46,XY,+1,der(1;10)(q10;p10), resulting in trisomy 1q and monosomy 10q abnormality. This finding suggests that either trisomy of 1q or centromeric connection between chromosomes 1 and 10, rather than the absence of 10q, might be essential toward neoplastic transformation.     

Wolf-Hirschhorn syndrome owing to 1:3 segregation of a maternal 4;21 translocation

We describe a child with Wolf-Hirschhorn syndrome with the karyotype 45,XY,inv(9)(p11q13)pat,-4,-21,+der(4),t(4;21)(p15.3;q11.2)mat. This is the second case known to us of Wolf-Hirschhorn syndrome caused by 1:3 segregation of a parental rearrangement. This mode of segregation can be predicted in both cases by a pachytene-diagram model. It is uncertain whether or not the proximal 21q monosomy in this case has affected the phenotype.     

Monosomy 13q32.3----qter: report of two cases.

Two unrelated patients with monosomy 13q32.3----qter are reported. Comparison with six similar cases previously published indicates that the craniofacial dysmorphism of the 13qter monosomy syndrome is related to band 13q34, the thumb hypoplasia to band 13q32, and an apparently different phenotype to band 13q33. Coagulation deficiency appears to be non-specific in monosomy 13qter.     

Isochromosome 18q with karyotype 46, XX, i(18q). Cytogenetics and pathology

Cytogenetic and morphological findings of a 20-gestational-week-old female fetus with karyotype 46,XX,i(18q) are reported. The fetus displayed clinical features resembling Edward's syndrome. No characteristic symptoms of monosomy 18p could be observed.