5q- syndrome
Encyclopedia
Chromosome 5q deletion syndrome (chromosome 5q monosomy
, 5q- syndrome) is a rare disorder
caused by loss of part of the long arm (q arm, band 5q31.1) of human chromosome 5.
It should not be confused with "partial trisomy
5q", though both conditions have been observed in the same family.
This should not be confused with cri du chat
syndrome which is a deletion of the short arm of the 5th chromosome.
, 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.
has been identified.
Deletion of the miR-145
and miR-146
loci has been associated with elevated platelet
count and megakaryocytic dysplasia associated with the 5q- syndrome.
cells causing treatment-resistant anemia
and myelodysplastic syndrome
s 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.
is a new agent that is showing promise in treating 5q- syndrome. It is approved for a subset of cases.
Monosomy
Monosomy is a form of aneuploidy with the presence of only one chromosome from a pair. Partial monosomy occurs when only a portion of the chromosome has one copy, while the rest has two copies.-Human monosomy:...
, 5q- syndrome) is a rare disorder
Disease
A disease is an abnormal condition affecting the body of an organism. It is often construed to be a medical condition associated with specific symptoms and signs. It may be caused by external factors, such as infectious disease, or it may be caused by internal dysfunctions, such as autoimmune...
caused by loss of part of the long arm (q arm, band 5q31.1) of human chromosome 5.
It should not be confused with "partial trisomy
Trisomy
A trisomy is a type of polysomy in which there are three copies, instead of the normal two, of a particular chromosome. A trisomy is a type of aneuploidy .-Description and causes:...
5q", though both conditions have been observed in the same family.
This should not be confused with cri du chat
Cri du chat
Cri du chat syndrome, also known as chromosome 5p deletion syndrome, 5p minus syndrome or Lejeune’s syndrome, is a rare genetic disorder due to a missing part of chromosome 5. Its name is a French term referring to the characteristic cat-like cry of affected children. It was first described by...
syndrome which is a deletion of the short arm of the 5th chromosome.
Characteristics
The 5q-syndrome is characterized by macrocytic anemia often thrombocytosisThrombocytosis
Thrombocytosis is the presence of high platelet counts in the blood, and can be either primary or reactive...
, 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
An association with RPS14RPS14
40S ribosomal protein S14 is a protein that in humans is encoded by the RPS14 gene.-Further reading:...
has been identified.
Deletion of the miR-145
Mir-145
In molecular biology mir-145 microRNA is a short RNA molecule. MicroRNAs function to regulate the expression levels of other genes by a several mechanisms.-Targets:MicroRNAs are involved in down regulation of a variety of target genes. Götte et al...
and miR-146
MiR-146
miR-146 is a family of microRNA precursors found in mammals, including humans. The ~22 nucleotide mature miRNA sequence is excised from the precusor hairpin by the enzyme Dicer. This sequence then associates with RISC which effects RNA interference....
loci has been associated with elevated platelet
Platelet
Platelets, or thrombocytes , are small,irregularly shaped clear cell fragments , 2–3 µm in diameter, which are derived from fragmentation of precursor megakaryocytes. The average lifespan of a platelet is normally just 5 to 9 days...
count and megakaryocytic dysplasia associated with the 5q- syndrome.
Histology
This syndrome affects bone marrowBone marrow
Bone marrow is the flexible tissue found in the interior of bones. In humans, bone marrow in large bones produces new blood cells. On average, bone marrow constitutes 4% of the total body mass of humans; in adults weighing 65 kg , bone marrow accounts for approximately 2.6 kg...
cells causing treatment-resistant anemia
Anemia
Anemia is a decrease in number of red blood cells or less than the normal quantity of hemoglobin in the blood. However, it can include decreased oxygen-binding ability of each hemoglobin molecule due to deformity or lack in numerical development as in some other types of hemoglobin...
and myelodysplastic syndrome
Myelodysplastic syndrome
The myelodysplastic syndromes are a diverse collection of hematological medical conditions that involve ineffective production of the myeloid class of blood cells....
s that may lead to acute myelogenous leukemia. Examination of the bone marrow
Bone marrow
Bone marrow is the flexible tissue found in the interior of bones. In humans, bone marrow in large bones produces new blood cells. On average, bone marrow constitutes 4% of the total body mass of humans; in adults weighing 65 kg , bone marrow accounts for approximately 2.6 kg...
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.
Treatment
LenalidomideLenalidomide
Lenalidomide , initially known as CC-5013 and marketed as Revlimid by Celgene, is a derivative of thalidomide introduced in 2004....
is a new agent that is showing promise in treating 5q- syndrome. It is approved for a subset of cases.