Chromosome 5q deletion syndrome

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Chromosome 5q deletion syndrome
Classification and external resources
5q- syndrome Bone marrow.jpg
Photomicrograph of bone marrow showing abnormal mononuclear megakaryocytes typical of 5q- syndrome
ICD-O: M9986/3
OMIM 153550
DiseasesDB 34573

Chromosome 5q deletion syndrome (chromosome 5q monosomy, 5q- syndrome) is an acquired, hematological disorder characterized by loss of part of the long arm (q arm, band 5q31.1) of human chromosome 5. This chromosome abnormality is most commonly associated with Myelodysplastic syndrome.

It should not be confused with "partial trisomy 5q", though both conditions have been observed in the same family.[1]

This should not be confused with cri du chat (5p deletion) syndrome which is a deletion of the short arm of the 5th chromosome.

Characteristics[edit]

The 5q-syndrome is characterized by macrocytic anemia often 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.

Causes[edit]

An association with RPS14 has been identified.[2]

Deletion of the miR-145 and miR-146 loci has been associated with elevated platelet count and megakaryocytic dysplasia associated with the 5q- syndrome.[3]

Histology[edit]

This syndrome affects bone marrow cells causing treatment-resistant anemia and myelodysplastic syndromes that may lead to acute myelogenous leukemia. Examination of the bone marrow shows characteristic changes in the megakaryocytes. They are more numerous than usual, small and mononuclear. There may be accompanying erythroid hypoplasia in the bone marrow.[4]

Treatment[edit]

Lenalidomide is a new agent that is showing promise in treating 5q- syndrome.[5] It is approved for a subset of cases.[6]

Prognosis[edit]

Most patients have a stable clinical course but are often transfusion dependent.

References[edit]

  1. ^ Lazjuk GI, Lurie IW, Kirillova IA et al. (August 1985). "Partial trisomy 5q and partial monosomy 5q within the same family". Clin. Genet. 28 (2): 122–9. doi:10.1111/j.1399-0004.1985.tb00371.x. PMID 4042393. 
  2. ^ Ebert BL, Pretz J, Bosco J et al. (January 2008). "Identification of RPS14 as a 5q- syndrome gene by RNA interference screen". Nature 451 (7176): 335–9. doi:10.1038/nature06494. PMID 18202658. 
  3. ^ Starczynowski DT, Kuchenbauer F, Argiropoulos B et al. (January 2010). "Identification of miR-145 and miR-146a as mediators of the 5q- syndrome phenotype". Nature Medicine 16 (1): 49–58. doi:10.1038/nm.2054. PMID 19898489. 
  4. ^ Online 'Mendelian Inheritance in Man' (OMIM) 5q- syndrome -153550
  5. ^ List A, Dewald G, Bennett J et al. (October 2006). "Lenalidomide in the myelodysplastic syndrome with chromosome 5q deletion". N. Engl. J. Med. 355 (14): 1456–65. doi:10.1056/NEJMoa061292. PMID 17021321. 
  6. ^ Raza A, Reeves JA, Feldman EJ et al. (January 2008). "Phase 2 study of lenalidomide in transfusion-dependent, low-risk, and intermediate-1 risk myelodysplastic syndromes with karyotypes other than deletion 5q". Blood 111 (1): 86–93. doi:10.1182/blood-2007-01-068833. PMID 17893227. 

External links[edit]