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Narrowing candidate region for monosomy 9p syndrome to a 4.7-Mb segment at 9p22.2-p23.

A 2-year-old boy with clinical manifestations of monosomy 9p syndrome and brown hair is described. G-banding and chromosome FISH studies demonstrated complex rearrangements involving seven breakpoints in chromosomes 2 and 9, which included a 6.6-Mb deletion at 9p22.2-p23. This, together with previous studies in the literature, narrowed the shortest region of overlap (SRO) for the syndrome to a 4.7-Mb interval. Candidate genes for trigonocephaly, mental retardation, and brown hair are discussed.

Abnormalities, Multiple↗

Monosomy 20: a nonrandom finding in childhood acute lymphoblastic leukemia.

We describe four cases of childhood acute lymphoblastic leukemia with monosomy 20 as the sole cytogenetic abnormality. These cases represent 3.4% of cytogenetically abnormal childhood ALL studied in our institute at diagnosis. The patients presented at similar age, ranging from 31 to 36 months. All four patients remain in first remission with survival time being at least 20 months from the time of diagnosis.

Antigens, CD↗

Molecular evidence that childhood monosomy 7 syndrome is distinct from juvenile chronic myelogenous leukemia and other childhood myeloproliferative disorders.

The observation that juvenile chronic myelogenous leukemia (JCML) and childhood bone marrow monosomy 7 syndrome (Mo 7) are similar in many clinical and epidemiologic respects suggests a shared pathogenic basis and raises the possibility that the bone marrows of patients with JCML might lose chromosome 7 alleles by mechanisms that do not result in detectable cytogenetic deletions. We used a series of polymorphic markers mapped to chromosome 7 to test this hypothesis in 22 children with MPS and MDS, including 19 with JCML. All MPS and MDS samples demonstrated allelic heterozygosity with at least one chromosome 7 marker; 16 were heterozygous with probes from both 7p and 7q. Furthermore, the percentage of patient bone marrow samples heterozygous at each locus tested was similar to the frequency observed in the normal population. Whereas these data demonstrate that submicroscopic loss of large segments of chromosome 7 alleles is uncommon in children with MPS and MDS who do not have Mo 7, they do not exclude small deletions around an uncharacterized tumor-suppressor locus. Our results suggest that a number of distinct molecular events contribute to leukemogenesis, and we propose a multistep model to explain the similarities and differences between the major subtypes of childhood MPS and MDS.

Child, Preschool↗

Reduced intensity hematopoietic stem-cell transplantation across human leukocyte antigen barriers in a patient with congenital amegakaryocytic thrombocytopenia and monosomy 7.

Congenital amegakaryocytic thrombocytopenia (CAMT) is a rare inherited bone marrow failure syndrome that has the potential to progress to pancytopenia and acute myeloid leukemia. Hematopoietic stem-cell transplantation (HSCT) is presently the only curative treatment approach. We used a reduced intensity transplantation regimen in a CAMT patient with aplastic anemia and monosomy 7 who had no matched related donor. The patient had rapid and durable engraftment with minimal complications and is well 24 months post-transplantation. Thus, reduced intensity conditioning might be a feasible approach to stem-cell transplantation in patients with CAMT who do not have a related donor and who are at increased risk of toxicity from standard conditioning regimens.

Anemia, Hypoplastic, Congenital↗

Prenatal diagnosis of monosomy 4p14-->pter and trisomy 11q25-->qter: clinical presentations and outcomes.

We present the case of a pregnant woman with low free beta-HCG in maternal serum Down syndrome screening that led to prenatal diagnosis of a fetus with 46,XY,der(4)t(4;11)(p14; q25). This chromosomal aneuploidy resulted from unbalanced segregation of a paternal balanced translocation, t(4;11)(p14;q25). Prenatal ultrasound revealed intrauterine growth restriction, cleft lip and palate, a thick nuchal fold, a single umbilical artery, and pyelectasis. Array-based comparative genomic hybridization and short tandem repeat markers further located the exact breakpoint of translocation. The woman had her pregnancy terminated at 23 weeks of gestational age. The proband had general appearance of Wolf-Hirschhorn syndrome and some unique findings, including single umbilical artery, severe immunoglobulin deficiency, scalp defect, and underlying bony defect. Our case underscores the importance of fetal karyotyping when low maternal serum free beta-HCG is found. It also adds information on the fetal presentations of monosomy 4p14-->pter and trisomy 11q25-->qter.

Abnormalities, Multiple↗

De novo monosomy 9p24.3-pter and trisomy 17q24.3-qter characterised by microarray comparative genomic hybridisation in a fetus with an increased nuchal translucency.

OBJECTIVES: Increased nuchal translucency (NT) during the first trimester of pregnancy is a useful marker to detect chromosomal abnormalities. Here, we report a prenatal case with molecular cytogenetic characterisation of an abnormal derivative chromosome 9 identified through NT. METHODS: Amniocentesis was performed because of an increased NT (4.4 mm) and showed an abnormal de novo 46,XX,add(9)(p24.3) karyotype. To characterise the origin of the small additional material on 9p, we performed a microarray comparative genomic hybridisation (microarray CGH) using a genomic DNA array providing an average of 1 Mb resolution. RESULTS: Microarray CGH showed a deletion of distal 9p and a trisomy of distal 17q. These results were confirmed by FISH analyses. Microarray CGH provided accurate information on the breakpoint regions and the size of both distal 9p deletion and distal 17q trisomy. The fetus was therefore a carrier of a de novo derivative chromosome 9 arising from a t(9;17)(p24.3;q24.3) translocation and generating a monosomy 9p24.3-pter and a trisomy 17q24.3-qter. CONCLUSION: This case illustrates that microarray CGH is a rapid, powerful and sensitive technology to identify small de novo unbalanced chromosomal abnormalities and can be applied in prenatal diagnosis.

Abnormalities, Multiple↗

Prenatal diagnosis of monosomy 18 and ring chromosome 18 mosaicism.

The case of monosomy 18/ring chromosome 18 mosaicism which was detected prenatally by amniocentesis is presented. The pregnancy was terminated in week 18. Autopsy showed complex malformation of the fetus consisting of cebocephaly, hypotelorism, microphthalmia, severe defects of brain development, and arrest of placental maturation.

Adult↗

Digeorge syndrome with total monosomy 22 diagnosed prenatally.

A case of monosomy 22 diagnosed prenatally is reported. During pregnancy, ultrasonic observations already revealed several cardiac malformations of the fetus in the 25th week. Following counselling, the pregnancy was terminated. Fetal autopsy revealed several abnormalities associated with DiGeorge syndrome.

Adult↗

Characterization of a novel gene, C21orf6, mapping to a critical region of chromosome 21q22.1 involved in the monosomy 21 phenotype and of its murine ortholog, orf5.

Phenotypic and molecular analyses of patients with partial chromosome 21 monosomy enabled us to define a region, spanning 2.4 Mb between D21S190 and D21S226, associated with arthrogryposis, mental retardation, hypertonia, and several facial anomalies. The markers of the region were used to screen a total human PAC library (Ioannou, RZPD). We isolated 57 PACs, which formed primary contigs. EST clusters (UNIGENE collection) located in a 6-Mb interval, between D21S260 and D21S263, were mapped in individual bacterial clones. We mapped the WI-17843 cluster to the PAC clone J12100, which contains the two anchor markers LB10T and LA329. The open reading frame extends over 960 bp, with three putative start codons. The 1695-bp cDNA containing a polyadenylation signal should correspond to the full-length cDNA. From the genomic sequence, we deduced that the gene contained five exons and that there was a putative promoter sequence upstream from exon 1. In silico screening of DNA databases revealed similarity with a murine EST. The corresponding cDNA (1757 bp) sequence was very similar (>85%) to the human cDNA and had an open reading frame of 876 nucleotides. Somatic hybrid mapping localized the cDNA to mouse chromosome 16. EST analyses and RT-PCR indicated that the third exon in the human gene (exon 2 in the mouse) undergoes alternative splicing. Northern blot hybridization showed that the gene was ubiquitously expressed in humans and mice. The longest mouse clone was used to generate riboprobes, which were hybridized to murine embryos at stages E-9.5, E-10.5, E-12.5, E-13.5, and E-14.5-15, to study the pattern of expression during development. Ubiquitous labeling was observed, with strong signals restricted to limited areas of the telencephalon, the mesencephalon, and the interrhombomeric regions in the central nervous system, and other regions of the body such as the limb buds, branchial arches, and somites.

Amino Acid Sequence↗

Pure monosomy and trisomy 2q24.2----q3105 due to an inv ins(7;2)(q21.2;q3105q24.2) segregating in four generations.

An inv ins(7;2)(q21.2;q3105q24.2) was found to segregate through four generations of a family. Adjacent-1 segregation aneusomies were ascertained in five patients: three monosomics and two trisomics; and the corresponding syndromes were delineated. The comparative analysis between these and other previously described 2q aneusomic individuals led to the conclusion that a large cleft between first and second toes is a constant feature in monosomy 2q24----q31. No other trait could plausibly be mapped. Risks of 7.9 to 31.6% for aneusomic children and of 26.3% for abortion were estimated in the present family.

Bone and Bones↗

Partial monosomy 5p and partial trisomy 5q due to paternal pericentric inversion of chromosome 5.

A male infant with partial monosomy 5p and partial trisomy 5q due to paternal pericentric inversion of chromosome 5 (46,XY,rec(5), dup q,inv(5)(p15.1q35.1)pat) is reported together with the oral findings. The phenotype was chiefly the cri-du-chat syndrome. Severe retardation of mental and motor development, microencephaly, cardiac malformation, crying and facial appearance unique to the cri-du-chat syndrome were observed. Perioral and intraoral findings included thin upper lip, down-turning corners of mouth, micrognathia, shallow palate, and cleft of soft palate. Anterior deciduous teeth were small and canine deciduous teeth were conic. The row of deciduous teeth showed a flat arch-like shape that was very wide but short in length. No abnormality was noted in the number of deciduous teeth or the timing of eruption.

Adult↗

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.

Abnormalities, Multiple↗

Small interstitial deletion of the long arm of chromosome 2 (2q24.3): further delineation of 2q medial monosomy syndrome.

We report on a female infant with an interstitial deletion involving 2q24.3. She had multiple congenital anomalies similar to those in patients with del(2)(q31q33) except for an occipital encephalocele. As a result of comparison of clinical findings among interstitial 2q deletions, a distinct 2q medial monosomy syndrome may be delineable in association with a deletion of 2q31.

Adult↗

Chromosome 22 monosomy in a radiation-induced meningioma.

We report for the first time on the cytogenetics of a radiation-induced meningioma, in a patient without neurofibromatosis. Chromosome 22 monosomy was found in more than 50% of the cells examined. These findings seem to suggest that the same kind of chromosomal aberrations are found in both "idiopathic" and radiation-induced meningiomas and that a common etiopathogenetic mechanism might be at work in meningiomas of whatever origin.

Chromosomes, Human, Pair 22↗

Platelet dysfunction as the presenting feature of atypical myelodysplastic syndrome with monosomy 7, normal blood counts and no bleeding tendency.

A 71-year-old male patient with atypical myelodysplastic syndrome showing monosomy 7 is described. He presented with severe foot pains, trophic skin and nail changes, loss of distal pulses, all compatible with peripheral arterial occlusive disease. He had completely normal blood counts and no bleeding tendency. Prolonged bleeding time was disclosed by chance, during routine haemostatic studies. An acquired platelet dysfunction was considered, with prolonged bleeding time and large platelets that failed to aggregate in response to arachidonic acid and that had impaired response to collagen and adrenaline. The bone marrow was hypercellular, with numerous dysplastic megakaryocytes and two other slightly dysplastic myeloid lines. Cytogenetic analyses of the bone marrow cells showed a mosaic karyotype: 46,XY/45,XY,-7. On angiography, bilateral thrombosis of the iliac, superficial femoral and popliteal was disclosed. The patient was prepared with platelet transfusions. Arterial thrombectomy and amputation of the left calf were performed. Ten months later, his blood counts showed mild pancytopenia. He died at home. The authors discuss some clinical and pathogenetical aspects of such presentations of myelodysplastic syndromes.

Aged↗

Transformation of severe aplastic anemia into acute myeloblastic leukemia with monosomy 7.

A cytogenetically normal man with severe aplastic anemia was treated with granulocyte colonystimulating factor (G-CSF), erythropoietin (EPO), cyclosporin A, anti-thymocyte globulin, and interleukin-6 (IL-6), which resulted in a gradual improvement in his neutrophil count and hemoglobin level. After 2 years of the therapy, monosomy 7 was detected during cytogenetic analysis of his bone marrow, which evolved during a period of 5 months into acute myeloblastic leukemia. An in vitro proliferation assay of cytokine responses showed that leukemic blasts were sensitive only to G-CSF, and not to EPO or IL-6. Although allogeneic bone marrow transplantation from an HLA-matched unrelated donor was carried out in the non-remission stage, the patient died of systemic fungal infection on day 25, without any evidence of hematological engraftment. As long-term use of cytokines and immunomo-suppressants in patients with severe aplastic anemia may induce or hasten the onset of a malignant transformation, careful attention must be paid to clonal evolution. Due to the poor prognosis of secondary myelodysplasia and leukemia, allogeneic bone marrow transplantation for such patients must be carried out early in the course of the disease.

Adult↗

CHARGE association-related ocular pathology in a newborn with partial trisomy 19q and partial monosomy 21q, from a maternal translocation (19;21) (q13.1;q22.3).

We report a novel case of partial trisomy 19q and concomitant partial monosomy 21q, segregated from a maternal translocation (19;21) (q13.1;q22.3), identified by spectral karyotyping. Clinical examination revealed dysmorphic features of the face and limbs, cleft palate, bilateral colobomas with associated bilateral colobomatous optic nerve cysts, hearing loss, and a cardiac anomaly. At autopsy, the dysmorphic features and cleft palate were confirmed. The ocular histopathology is described in detail and the cardiac anomaly was further specified. The combination of phenotype features is diagnostic of the CHARGE (coloboma, heart malformation, atresia choanae, retarded growth and development, and/or CNS anomalies, genital hypoplasia, ear anomalies and/or deafness) association. This case also has some phenotypic features in common with previous cases of partial trisomy 19q. The importance of a complete autopsy in cases with multiple congenital anomalies and/or genetic abnormalities is emphasized. This will allow optimal genetic counseling and contribute to our understanding of developmental biology.

Abnormalities, Multiple↗