5q deletion syndrome

Chromosome 5q deletion syndrome is an acquired, hematological disorder characterized by loss of part of the long arm (q arm, band 5q33.1) of human chromosome 5 in bone marrow myelocyte cells. 


It is chromosome abnormality is most commonly associated with the myelodysplastic syndrome.


The 5q-syndrome is characterized by macrocytic anemia, often moderate thrombocytosis, erythroblastopenia, megakaryocyte hyperplasia with nuclear hypolobation, and an isolated interstitial deletion of chromosome 5. 


The 5q- syndrome is found predominantly in females of advanced age.


Several genes in the deleted region appear to play a role in the pathogenesis of 5q-syndrome: Haploinsufficiency of RPS14, miR-145 and miR-146a, SPARC, EGR1, CTNNA1, and CDC25C.


Haploinsufficiency of RPS14 contributes to the anemia via both p53-dependent and p53-independent tumor suppressor effects.


miR-145 and miR-146a  deletion is associated with the megakaryocytic dysplasia and thrombocytosis seen in 5q- syndrome


The 5q deletion syndrome causing treatment-resistant anemia and myelodysplastic syndromes that may lead to acute myelogenous leukemia. 


Bone marrow exam demonstrates more numerous megakaryocytes, although small and mononuclear.


Examination of the bone marrow shows characteristic changes in the megakaryocytes: more numerous than usual,  small and mononuclear. 


Erythroid hypoplasia in the bone marrow may be present.


Lenalidomide has activity in 5q- syndrome.and is approved for red blood cell (RBC) transfusion-dependent anemia due to low or intermediate-1 (risk myelodysplastic syndrome (MDS) associated with chromosome 5q deletion with or without additional cytogenetic abnormalities.

Treatment responds to lenalidomide is 50 to 80%, and responses are typically deep and durable,  with an average response lasting greater than 1.5 years, and many responses exceeding two years.


Most affected people have a stable clinical course.


Many patients but are transfusion dependent.

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