Myelodysplasia and leukemia syndrome with monosomy 7: a genetic perspective

Acquired monosomy 7 is a frequent finding in myelodysplastic syndromes, including acute myelogenous leukemia. A subset of these patients has been described with an apparently distinct condition: myelodysplasia and leukemia syndrome with monosomy 7 (MLSM7). We report 2 brothers, 3 and 5 years of age, with MLSM7 and review other reports of familial occurrence. Genetic factors appear to be important in the cause of MLSM7, but the reported families do not fit neatly into any monogenic pattern. Recognition of the frequently familial nature of this condition requires hematological evaluation and genetic counseling for the families of patients with MLSM7.

Translocations and deletions with breakpoint on 21q are nonrandomly associated with treatment-related acute nonlymphocytic leukemia and preleukemia

Six of 70 (8.6%) consecutive cases with therapy-related acute nonlymphocytic leukemia (ANLL) or preleukemia had a translocation or deletion with a breakpoint on 21q. Such aberrations were seen in only one of 200 (0.5%) consecutive cases of de novo ANLL examined at our laboratory. The figures reflect a 17.1-fold increased incidence of 21q aberrations in therapy-related ANLL or preleukemia, compared with ANLL de novo. The difference is highly significant (p = 0.003). The increased incidence of 21q aberrations in therapy-related myelodysplastic syndromes was confirmed by literature studies. Band 21q22 was most often involved. Cases with t(8;21), which is strongly associated with the M2 variant of ANLL, or cases with i(21q), which is supposedly due to a centromeric misdivision, were not included in the count. It is concluded that the 21q aberrations are associated with treatment-related ANLL or preleukemia with at least the same degree of specificity as aberrations of #5 and #7.

Simple monosomy 7 and myelodysplastic syndrome in thirteen patients without previous cytostatic treatment

Thirteen patients with simple monosomy 7 presented with pallor in 11, easy bruisability in five, splenomegaly in four, no infections, refractory anaemia in all, granulocytopenia in seven, monocytosis in three, leucocytosis in four and thrombocytopenia in eight. Peripheral blood and bone marrow findings were consistent with myelodysplastic syndrome (MDS) type I in three, type II in two, type III in two, type IV in three and acute myelofibrosis in three patients. Transformations to acute leukaemia in seven patients were M2 in one, M4 in four, megakaryoblastic in one and undifferentiated in one. Lack of chromosome 7 in 12-85% of analysed cells at initial presentation of MDS progressed to nearly 100% during blastic transformation. At that time an additional change in the long arm of chromosome 3 was seen in two patients and trisomy 8 in 6% of analysed cells in a third case. The median survival time was 12 months for MDS and 3 months for acute leukaemia. Simple monosomy 7 appears to be largely confined to young children and elderly people.

Bone marrow monosomy 7: hematologic and clinical manifestations in childhood and adolescence

The hematologic manifestations and clinical course are described for six children and adolescents with bone marrow monosomy 7. One child with secondary acute myelogenous leukemia had monosomy 7 plus a marker chromosome; the remaining patients had marrow monosomy 7 as the only karyotypic abnormality. The hematologic abnormalities were diverse, but the majority of patients had a smoldering preleukemic or myeloproliferative phase. Leukemic blasts were either undifferentiated or demonstrated evidence of myeloid differentiation. All patients responded poorly to antileukemic therapy. Bone marrow monosomy 7 was observed in one patient with severe marrow hypoplasia. Antileukemic therapy in another patient with greater than 30 per cent marrow blasts was associated with the development of a bone marrow myeloproliferative disorder with persistence of the monosomy 7 karyotype. We speculate that monosomy 7 may be a specific marker for a pluripotent hematopoietic stem cell abnormality that is associated with either blastic leukemia or a myeloproliferative disorder.

Pathogenetic significance of "pure" monosomy 7 in myeloproliferative disorders. Analysis of 14 cases

Monosomy 7 is frequent in acute myeloid leukaemia (AML) and in preleukaemic dysmyelopoietic syndromes but often it is not the only chromosome anomaly associated with these conditions. We report 14 patients with "pure" monosomy 7 and their clinical and haematological data are analysed in order to clarify the possible implications of this chromosome anomaly. The following points are considered: 1) In spite of the apparent variability of clinical forms in which monosomy 7 is found, several characteristics are common to all monosomy 7 patients, i.e. the presence of a preleukaemic phase and blood and marrow features suggesting the early involvement in the disease of all marrow cell lines. The different diagnoses associated with monosomy 7 are correlated with different steps of a unique myeloproliferative disease whose typical course can be reconstructed. 2) Monosomy 7 has a negative prognostic value. When it is found in a preleukaemic disorder it indicates a high risk of progression to AML, while in AML it implies recurrent infections, poor response to therapy and short survival. 3) The significance of the lack of Colton blood group antigens in monosomy 7 patients is discussed, with particular regard to the fact that the patients in whom this lack was found are the only ones who had not received transfusions in the months before the tests were done. 4) The finding of defective neutrophil chemotaxis in monosomy 7 patients is confirmed and the clinical importance of this fact is emphasized. 5) The data on the 14 patients support the opinion that AML, in general, is heterogeneous in origin. It is postulated that monosomy 7 is a marker of a specific pathogenetic pathway of AML, which implies the beginning of the malignancy in a pluripotent stem cell.

Ataxia-pancytopenia: syndrome of cerebellar ataxia, hypoplastic anemia, monosomy 7, and acute myelogenous leukemia

In a family with ataxia and pancytopenia, the proband had cerebellar ataxia, developed hypoplastic anemia at age 3 years, and died of acute myelomonocytic leukemia at age 7. Serial cytogenetic studies of the proband's hypoplastic bone marrow over a 25-month period revealed progressive expansion of a clone of cells with C(6 - 12 + X) monosomy from 33% to 94% of metaphases. The missing chromosome by banding was deduced to be No.7. No increased sensitivity of the patient's cells was found in response to ultraviolet or ionizing radiation or to mitomycin C. Cerebellar atrophy was confirmed at autopsy. Family studies revealed cerebellar ataxia in the proband's father and all four siblings. Two brothers, including one with C-monosomy, died with hypoplastic anemia and another brother died with acute myelocytic leukemia. The only surviving sibling is a 19-year-old sister who has unexplained anemia, decreased mitotic activity in bone marrow, and slow progressive cerebellar ataxia. The name ataxia-pancytopenia syndrome is proposed to encourage study of additional patients with this disorder, which predisposes to pancytopenia and acute leukemia.

A family with acute leukemia, hypoplastic anemia and cerebellar ataxia: association with bone marrow C-monosomy

The eldest brother in a sibship of five children died of acute myelogenous leukemia at 10 years of age. The second and third eldest brothers died of hypoplastic anemia at ages five and nine years, respectively. A surviving 6 year old brother, the proband of the study, has abnormalities that suggest a preleukemic state: mild pancytopenia, platelet dysfunction, immunodeficiency, and bone marrow hypoplasia with approximately 18 per cent blast forms. His 17 year old sister has a mild normochromic normocytic anemia. Cytogenetic studies revealed C-group monosomy in the bone marrows of the proband and the third brother (45, XY, -C); band studies demonstrated that a No. 8 chromosome was missing in the proband (45, XY, -8). At least four of the siblings and their father had cerebellar ataxia, and evidence of a small cerebellum at autopsy examination or by computerized axial tomography. The disorder in this family has major features of two autosomal recessive preleukemic diseases, ataxia-telangiectasia and Fanconi's anemia. However, these and other inherited conditions were excluded by clinical or laboratory criteria, and no environmental causes of the familial disorder were found. The constellation of abnormalities in the family may constitute a new genetic syndrome.