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PubMed1997

Monosomy 7 myelodysplastic syndrome and other second malignant neoplasms in children with neurofibromatosis type 1.

BACKGROUND: Children with neurofibromatosis type 1 (NF1) are at increased risk of developing benign and malignant solid tumors as well as hematologic malignancies, including de novo juvenile chronic myelogenous leukemia, monosomy 7 syndrome, and acute myelogenous leukemia. The normal NF1 allele is frequently deleted in the bone marrow cells from NF1 patients with hematologic malignancies, suggesting a pathogenic role in primary leukemogenesis. The authors report monosomy 7 myelodysplastic syndrome (MDS) as a second malignant neoplasm (SMN) in five children with sporadic NF1, the results of molecular analysis for NF1 and ras alterations in their bone marrow, and summarize their experience with SMNs in pediatric patients with NF1. METHODS: Monosomy 7 MDS was diagnosed as an SMN in five children with NF1 by morphologic and cytogenetic studies of bone marrow specimens. DNA extracted from these malignant bone marrows was analyzed for allelic loss at the NF1 locus and for the presence of ras mutations. The Children's Hospital of Philadelphia (CHOP) Tumor Registry was also reviewed to estimate the incidence of SMNs in pediatric NF1 patients. RESULTS: Bone marrow specimens from four patients retained constitutional heterozygosity at the NF1 locus; one specimen was uninformative. There was no evidence of activating ras mutations. The risk of an SMN was approximately 11% among the 64 NF1 registrants with primary malignancies in the CHOP registry, but was 75% (6 of 8) among patients treated for a pediatric embryonal cancer. CONCLUSIONS: Children with NF1 are susceptible to the development of malignant myeloid disorders both as a primary event and as an SMN. Additional molecular genetic analysis is necessary to determine if the NF1 gene is inactivated by somatic mutation in these secondary leukemias.

Blotting, Southern↗
PubMed1998

Low-level mosaicism for both trisomy 15 and monosomy-X in amniotic fluid cells confirmed in fetal tissues.

We report here a case of true fetal mosaicism for both trisomy 15 and monosomy-X; the aberrant cell lines were initially detected at amniocentesis as low-level mosaicism (trisomy 15) and multiple-cell pseudo-mosaicism (monosomy-X). In the fetal lymphocytes, only metaphases with a normal chromosome complement were observed. After termination of the pregnancy, various fetal biopsies revealed both trisomy 15 and monosomy-X mosaicism, whereas, at autopsy, no external or internal abnormalities could be detected in the fetus. The karyotype can be described as 45,X[15]/47,XY,+15[3]/46,XY[27]. Our results implicate that an additional amniocentesis could be more helpful than fetal blood sampling in predicting the fetal karyotype after diagnosis of chromosome mosaicism at amniocentesis.

Adult↗
PubMed2001

Prenatal diagnosis of partial monosomy 18p(18p11.2-->pter) and trisomy 21q(21q22.3-->qter) with alobar holoprosencephaly and premaxillary agenesis.

A prenatal diagnosis of partial monosomy 18p(18p11.2-->pter) and trisomy 21q(21q22.3-->qter) in a fetus with alobar holoprosencephaly (HPE) and premaxillary agenesis (PMA) but without the classical Down syndrome phenotype is reported. A 27-year-old primigravida woman was referred for genetic counselling at 21 weeks' gestation due to sonographic findings of craniofacial abnormalities. Level II ultrasonograms manifested alobar HPE and median orofacial cleft. Cytogenetic analysis and fluorescence in situ hybridization (FISH) on cells obtained from amniocentesis revealed partial monosomy 18p and a cryptic duplication of 21q,46,XY,der(18)t(18;21)(p11.2;q22.3), resulting from a maternal t(18;21) reciprocal translocation. The breakpoints were ascertained by molecular genetic analysis. The pregnancy was terminated. Autopsy showed alobar HPE with PMA, pituitary dysplasia, clinodactyly and classical 18p deletion phenotype but without the presence of major typical phenotypic features of Down syndrome. The phenotype of this antenatally diagnosed case is compared with those observed in six previously reported cases with monosomy 18p due to 18;21 translocation. The present study is the first report of concomitant deletion of HPE critical region of chromosome 18p11.3 and cryptic duplication of a small segment of distal chromosome 21q22.3 outside Down syndrome critical region. The present study shows that cytogenetic analyses are important in detecting chromosomal aberrations in pregnancies with prenatally detected craniofacial abnormalities, and adjunctive molecular investigations are useful in elucidating the genetic pathogenesis of dysmorphism.

Adult↗
PubMed1979

A low frequency mosaicism for monosomy 21 in a live born female.

Monosomy 21, whether homogeneous or as a mosaicism, is very uncommon. We report here a 3-month-old white female with a low degree of monosomy 21 in the blood karyotype (6.5%, 110 cells counted) but not in the skin fibroblasts, which contained only the normal chromosome complement. The patient's physical features included microcephaly with frontal slanting; prominent occiput; ridge-shaped sutures; agenesis of the corpus callosum; large, prominent ears; high and narrow palate; micrognathia; tetralogy of Fallot; crowded toes; and dry, thick skin with very little subcutaneous tissue. The case is discussed in light of the suggested clinical features of the "monosomy 21" syndrome and the possible implications of such a low-grade mosaicism in prenatal diagnosis.

Abnormalities, Multiple↗
PubMed2002

Expression and mutation analysis of BRUNOL3, a candidate gene for heart and thymus developmental defects associated with partial monosomy 10p.

Partial monosomy 10p is a rare chromosomal aberration. Patients often show symptoms of the DiGeorge/velocardiofacial syndrome spectrum. The phenotype is the result of haploinsufficiency of at least two regions on 10p, the HDR1 region associated with hypoparathyroidism, sensorineural deafness, and renal defects (HDR syndrome) and the more proximal region DGCR2 responsible for heart defects and thymus hypoplasia/aplasia. While GATA3 was identified as the disease causing gene for HDR syndrome, no genes have been identified thus far for the symptoms associated with DGCR2 haploinsufficiency. We constructed a deletion map of partial monosomy 10p patients and narrowed the critical region DGCR2 to about 300 kb. The genomic draft sequence of this region contains only one known gene, BRUNOL3 ( NAPOR, CUGBP2, ETR3). In situ hybridization of human embryos and fetuses revealed as well as in other tissues a strong expression of BRUNOL3 in thymus during different developmental stages. BRUNOL3 appears to be an important factor for thymus development and is therefore a candidate gene for the thymus hypoplasia/aplasia seen in partial monosomy 10p patients. We did not find BRUNOL3 mutations in 92 DiGeorge syndrome-like patients without chromosomal deletions and in 8 parents with congenital heart defect children.

Adult↗
PubMed2004

Mosaic monosomy 14: clinical features and recognizable facies.

A 1-year-old child with clinical features of monosomy 14 is reported. She has dysmorphic facial features including ocular colobomata, dolichocephaly and microcephaly, retinal pigmentation, severe seizures, fair curly hair and tapering fingers. There was severe mental retardation. This is the first reported case of severe mosaic monosomy 14, with up to 30% mosaicism. A recognizable facial gestalt is present in children with 14q deletions or partial monosomy 14, as well as susceptibility to infection, feeding difficulties, seizures and retinal pigmentation.

Brain↗
PubMed1977

Monosomy 7 in two patients with a myeloproliferative disorder.

Clinical and laboratory data are presented for two patients with a dyshaematopoietic disorder, and monosomy 7 in their bone marrow cells. The first patient, a 55-year-old woman, had been treated with chlorambucil for an ovarian carcinoma. After 4 years an oligoblastic myeloid leukaemia was diagnosed and she later died with an acute transformation of the disease. The second patient, a 21-year-old male, has had a dyserythropoietic anaemia with transient pancytopenia for over 5 years without any signs of malignancy. The possible relationship between therapy, the monosomy 7 and the other bone marrow abnormalities is briefly discussed. From an analysis of the data of these and comparable cases in the literature it appears that loss of chromosome No. 7 material is often associated with erythropoietic disorders such as erythroid hyperplasia and erythraemia. The reduction or absence of the Colton blood group antigens found in our patients and in a few other monosomy 7 cases also points to an abnormality of the red cell line.

Adolescent↗
PubMed1985

Serial cell culture and cytogenetic studies of marrow cells from a patient with monosomy 7 syndrome.

Serial bone marrow cell culture studies, with cytogenetic characterization, were performed in an 18-month-old boy with monosomy 7 syndrome--a condition that usually converts to nonlymphoblastic leukemia. Over a 12-month course, his marrow demonstrated: decreased colony formation and increased cluster formation in vitro with disease progression (consistent with preleukemia); persistence of only the monosomy 7 karyotype in direct marrow studies; and in contrast, proliferation of both 46,XY and monosomy 7 cells in in vitro marrow cultures. The findings indicate that certain dormant marrow cell populations may be expressed under in vitro culture conditions and suggest the need for determining factors which would allow their expression in vivo.

Bone Marrow↗
PubMed1983

Gene dosage effect for beta-glucuronidase (GUSB) in monosomy 7 cells of patients with myeloproliferative disorders.

The demonstration of a gene dosage effect in a neoplastic cell with a specific chromosome abnormality could be helpful in the study of some pathogenetic steps of the malignant growth. We tested the activities of beta-glucuronidase (GUSB), whose gene is mapped on chromosome 7 and of Arylsulphatase A (ARSA) and beta-galactosidase (GLB) as control lysosomal enzymes, whose loci are not assigned to number 7, in a group of 10 patients with myeloproliferative disorders associated with monosomy 7. A significant difference of the levels of activity of GUSB in monosomy 7 cells was found in comparison with two groups of controls, one of healthy subjects, the other of patients with similar disorders without monosomy 7. These results indicate the presence of a gene dosage effect for GUSB.

Anemia, Sideroblastic↗
PubMed1981

Simultaneous trisomy 10q24 leads to qter and monosomy 4p16: an example of epistasis at the chromosome level.

A family with a reciprocal translocation (4;10)(p16;q24) leading to a simultaneous 10q24 leads to qter trisomy and partial 4p16 monosomy in two females (niece and aunt) is described. Comparative analysis with previously reported cases corroborates a distinctive dysmorphic syndrome due to the 10q24 leads to qter trisomy whose phenotypical expression is dominant over that of the 4p16 monosomy and those produced by other partial monosomies. This phenomenon is interpreted as epistasis at the chromosome level.

Abnormalities, Multiple↗
PubMed1995

DiGeorge syndrome and partial monosomy 10p: case report and review.

DiGeorge syndrome (DGS) is predominantly caused by partial monosomy 22q11, but a subset of patients with DGS show deletions of 10p or other chromosomal abnormalities. The authors describe a 20 months old girl with DGS and a monosomy 10p bringing the number of DGS patients with this chromosomal abnormality to nine. She has a monosomy 10p13-pter and a trisomy 10q26-qter due to a meiotic recombination of a maternal inversion (10) (p13q26). The proposita's phenotype demonstrates typical features of the del (10p) syndrome which include mental retardation, abnormally shaped skull, hypertelorism, low nasal bridge, micrognathia, dysmorphic low set ears, short neck, foot abnormalities, and cardiac defect. The diagnosis of DGS was made unequivocally within the first weeks of life because of the typical features-cardiac defect, hypoplastic thymus, T-cell defect, hypocalcemia, and hypoparathyroidism. The common DGS mutation-microdeletion 22q11-was excluded by FISH analysis, and the breakpoints on chromosome 10 were mapped between D10S189 and D10S191 on the short arm and proximal to D10S25 on the long arm.

Chromosome Deletion↗
PubMed1996

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.

Child, Preschool↗
PubMed1996

Monosomy 6q1: syndrome delineation.

We report on a girl with a de novo 6q1 interstitial deletion. To our knowledge, this is the second reported case with a deletion of 6q11-q15. We review the phenotype of monosomy 6q1. Our patient has manifestations similar to others with monosomy 6q1 including mental deficiency, growth retardation, short neck, and minor facial anomalies.

Abnormalities, Multiple↗
PubMed1996

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.

Adolescent↗
PubMed1996

New form of bone dysplasia with multiple fractures associated with monosomy X.

We report on the clinical, radiologic, and pathologic findings in a 20-week-old fetus with monosomy X and severe hydrops associated with fetal dwarfism. The fetus presented with osteoporosis, bent bones, multiple fractures, and distinctive symmetric submetaphyseal transverse bone interruptions or pseudofractures. We excluded by radiologic and histopathologic examination the diagnoses of osteogenesis imperfecta, hypophosphatasia, campomelic dysplasia, achondrogenesis, hypochondrogenesis, and other types of bone dysplasia. To our knowledge, this is a previously undescribed bone dysplasia associated with monosomy X. This bone dysplasia may be inherited as an X-linked recessive disorder.

Bone Diseases, Developmental↗
PubMed1997

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."

Chromosomes, Human, Pair 21↗
PubMed1996

Familial sideroblastic anemia with emergence of monosomy 5 and myelodysplastic syndrome.

The case history of two sisters with pyridoxine-refractory familial sideroblastic anemia (FSA) is presented in which one developed a myelodysplastic syndrome (MDS) with monosomy for chromosome 5. Bone marrow examination of both patients at diagnosis showed erythroid hyperplasia with more than 50% ring sideroblasts. Karyotypic analysis initially showed a normal 46, XX karyotype in both of the children. Therapeutic trials with pyridoxine, prednisone, and erythropoietin were unsuccessful. The first patient required regular transfusions and developed a significant hemosiderosis. At the age of 9 years, 7.5 years after the diagnosis of FSA, refractory anemia with excess of blasts (RAEB) was diagnosed. Bone marrow cytogenetic analysis revealed a clone with monosomy for chromosome 5. Her sister's illness was detected at the age of 12 years. She has a more benign course of disease, remains largely transfusion independent and until now shows no signs of myelodysplasia. To our knowledge this is the first observation of a transition of FSA to MDS accompanied by the appearance of a chromosomal abnormality. FSA might be another type of bone marrow failure syndrome, therefore close follow-up of these patients may be necessary.

Anemia, Refractory, with Excess of Blasts↗
PubMed1998

Partial trisomy 8q and partial monosomy 15q associated with congenital hydrocephalus, diaphragmatic hernia, urinary tract anomalies, congenital heart defect and kyphoscoliosis.

We describe perinatal findings in a female fetus with partial trisomy 8q(8q24.1-->8qter) and partial monosomy 15q(15q26.1-->15qter) resulting from a paternal t(8;15) reciprocal translocation. Prenatal sonographic examination showed intra-uterine growth retardation, bilateral ventriculomegaly, cardiomegaly with arrhythmia, anhydramnios, and absent kidney and urinary bladder images. The pregnancy was terminated at 28 weeks of gestation. At birth, the infant manifested typical dysmorphic features of partial trisomy 8q. Necropsy further revealed hydrocephalus, congenital diaphragmatic hernia, ventricular septal defect, a horseshoe kidney with renal hypoplasia, and kyphoscoliosis. Our case shows that the coexistence of partial trisomy 8q24.1-->8qter and partial monosomy 15q26.1-->15qter are more detrimental than either defect alone and can result in a complex of major malformations. Prenatal ultrasound examination and cytogenetic assessment should be offered in subsequent pregnancies.

Abnormalities, Multiple↗