t(1;22)(p13;q13) RBM15/MKL1

2001-06-01   Jean-Loup Huret 

1.Genetics, Dept Medical Information, University of Poitiers, CHU Poitiers Hospital, F-86021 Poitiers France

Clinics and Pathology

Disease

only found so far in M7 AML (acute megakaryocytic leukaemia); not found in Down syndrome (DS), and yet, DS is a disease with highly elevated risk of M7 (see leukaemia and Down Syndrome); misdiagnoses of a solid tumour have been documented

Phenotype stem cell origin

megakaryocytic

Etiology

no known toxic exposure

Epidemiology

about 40 known cases; 0% to 3% of paediatric AML; 70 to 100% of infants M7; age: infants: median age 4 mths; 20% are < 1mth; 80% are < 1 yr; 95% are < 2 yrs; sex ratio: 15M/24F (non significant)

Clinics

no preceeding myelodysplasia, and no history of transient leukemoid reaction; prominent organomegaly; blood data: moderate WBC; thrombocytopenia; myelofibrosis and fibrosis of other organs

Cytology

platelet-specific markers: platelet-peroxidase by electron microscopy, or platelet glycoproteins IIb/IIIa (CD41) or IIIa (CD61)

Treatment

bone marrow transplantation is indicated

Prognosis

complete remission in only 50% of cases; median survival: 8 months; a few long survivors; absence of a prognostic indicator

Cytogenetics

Additional anomalies

60% of cases (mostly patients under 6 mths of age) have the t(1;22) as a single anomaly; the remaining third of cases (mainly patients above the age of 6 mths) exhibit complex and hyperploid clones, with a highly monomorph pattern: +2, +19, +der(1)t(1;22), +6, +21 were found in more than 50% of cases each, +10, +7, +15, +18, +8, +20, del(1p), +4, +9, +14, +17, add(21p) are also recurrent; survival was equivalent in cases with or without a complex karyotype; the frequent presence of an additional der(1) indicates that the crucial event is likely to lie on the der(1)t(1;22)

Variants

2 cases of complex t(1;22) with a third chromosome have been described

Genes Involved and Proteins

Gene name
RBM15 (RNA binding motif protein 15)
Location
1p13.3
Protein description
contains RNA recognition motif consensus
Gene name
MKL1 (megakaryoblastic leukemia (translocation) 1)
Location
22q13.1
Protein description
931 amino acids; could attach DNA to nuclear scaffold and be involved in chromatin organization

Result of the Chromosomal Anomaly

Description

5 OTT - 3 MAL, comprisng most of OTT fused to most of MAL; the reciprocal 5 MAL - 3 OTT may or may not be present

Oncogenesis

may modulate chromatin organization, HOX differentiation pathways, or extracellular signaling

Bibliography

No bibliography items were found for this article.

Summary

Fusion gene

RBM15/MKL1 RBM15 (1p13.3) MKL1 (22q13.1) M|RBM15/MKL1 RBM15 (1p13.3) MKL1 (22q13.1) M t(1;22)(p13;q13)
Atlas Image
t(1;22)(p13;q13) G- and R- banding

Citation

Jean-Loup Huret

t(1;22)(p13;q13) RBM15/MKL1

Atlas Genet Cytogenet Oncol Haematol. 2001-06-01

Online version: http://atlasgeneticsoncology.org/haematological/1005/t(1;22)(p13;q13)

Historical Card

1999-11-01 t(1;22)(p13;q13) RBM15/MKL1 by  Jean-Loup Huret 

Genetics, Dept Medical Information, University of Poitiers, CHU Poitiers Hospital, F-86021 Poitiers France

1998-01-01 t(1;22)(p13;q13) RBM15/MKL1 by  Jean-Loup Huret 

Genetics, Dept Medical Information, University of Poitiers, CHU Poitiers Hospital, F-86021 Poitiers France

1997-08-01 t(1;22)(p13;q13) RBM15/MKL1 by  Jean-Loup Huret,Jean-Loup Huret 

Genetics, Dept Medical Information, University of Poitiers, CHU Poitiers Hospital, F-86021 Poitiers France

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