R21
MCID: RNG017
MIFTS: 31

Ring Chromosome 21 (R21)

Categories: Ear diseases, Eye diseases, Fetal diseases, Immune diseases, Mental diseases, Neuronal diseases, Rare diseases, Reproductive diseases

Aliases & Classifications for Ring Chromosome 21

Summaries for Ring Chromosome 21

GARD : 20 Ring chromosome 21 is a rare chromosome abnormality in which the ends of chromosome 21 join together to form a ring shape. Many people with ring chromosome 21 have normal development and are healthy, having been diagnosed after having chromosome testing due to infertility, multiple miscarriages, or a child with a chromosome abnormality. However, others with ring chromosome 21 have developmental and/or medical problems which can range from mild to severe. This is due to having extra or missing genetic material on the ring chromosome, which can happen when the ring chromosome forms. Signs and symptoms of ring chromosome 21 that may be present can include short stature, delayed puberty in males, small head size, seizures, learning disabilities, underdeveloped sex organs, susceptibility to infections, and/or a variety of birth defects. Some people have signs and symptoms similar to those that occur in people with Down syndrome. Ring chromosome 21 may be inherited from a parent (typically the mother), or it may occur sporadically (by chance) during the formation of egg or sperm cells or shortly after the egg and sperm join together. A chromosome test of the parents can help determine whether it was inherited and whether future children have an increased chance to have a chromosome abnormality. Treatment for ring chromosome 21 depends on the signs and symptoms present in each person.

MalaCards based summary : Ring Chromosome 21, also known as ring chromosome 21 syndrome, is related to ring chromosome and acute myeloid leukemia with abnormal bone marrow eosinophils inv(16)(p13q22) or t(16;16)(p13;q22). An important gene associated with Ring Chromosome 21 is ETV6 (ETS Variant Transcription Factor 6), and among its related pathways/superpathways is Transcriptional misregulation in cancer. Affiliated tissues include heart and myeloid, and related phenotypes are abnormal facial shape and intellectual disability

Related Diseases for Ring Chromosome 21

Diseases in the Ring Chromosome family:

Ring Chromosome 14 Syndrome Ring Chromosome 1
Ring Chromosome 10 Ring Chromosome 11
Ring Chromosome 12 Ring Chromosome 13
Ring Chromosome 15 Ring Chromosome 16
Ring Chromosome 17 Ring Chromosome 18
Ring Chromosome 19 Ring Chromosome 2
Ring Chromosome 20 Ring Chromosome 21
Ring Chromosome 22 Ring Chromosome 3
Ring Chromosome 4 Ring Chromosome 5
Ring Chromosome 6 Ring Chromosome 7
Ring Chromosome 8 Ring Chromosome 9
Ring Chromosome Y Syndrome

Diseases related to Ring Chromosome 21 via text searches within MalaCards or GeneCards Suite gene sharing:

(show top 50) (show all 71)
# Related Disease Score Top Affiliating Genes
1 ring chromosome 30.9 KMT2A ETV6
2 acute myeloid leukemia with abnormal bone marrow eosinophils inv(16)(p13q22) or t(16;16)(p13;q22) 29.6 KMT2A ETV6
3 myeloid leukemia 29.6 KMT2A ETV6
4 leukemia, acute lymphoblastic 29.6 KMT2A ETV6
5 leukemia 29.4 KMT2A ETV6
6 myelodysplastic syndrome 29.2 KMT2A ETV6
7 leukemia, acute myeloid 29.0 KMT2A ETV6
8 muscular dystrophy, limb-girdle, autosomal recessive 21 11.1
9 down syndrome 10.3
10 monosomy 21 10.2
11 chromosomal triplication 10.1
12 lentigines 10.1
13 eating disorder 10.1
14 microcephaly 10.0
15 teratoma 10.0
16 holoprosencephaly 10.0
17 sacrococcygeal teratoma 10.0
18 microphthalmia 9.9
19 melanoma 9.9
20 cri-du-chat syndrome 9.9
21 hypertelorism 9.9
22 nondisjunction 9.9
23 optic nerve hypoplasia, bilateral 9.9
24 otitis media 9.9
25 duodenal atresia 9.9
26 immune deficiency disease 9.9
27 chromosome 18q deletion syndrome 9.9
28 patent ductus arteriosus 1 9.9
29 alacrima, achalasia, and mental retardation syndrome 9.9
30 cervical dystonia 9.9
31 alexithymia 9.9
32 scoliosis 9.9
33 isolated ectopia lentis 9.9
34 combined immunodeficiency 9.9
35 myopia 9.9
36 azoospermia 9.9
37 heart septal defect 9.9
38 atrial heart septal defect 9.9
39 dystonia 9.9
40 hypermobile ehlers-danlos syndrome 9.9
41 ring chromosome 2 9.9
42 hypertonia 9.9
43 hypotonia 9.9
44 b-lymphoblastic leukemia/lymphoma 9.8 KMT2A ETV6
45 b-lymphoblastic leukemia/lymphoma with iamp21 9.8 KMT2A ETV6
46 leukemia, acute lymphoblastic 3 9.8 KMT2A ETV6
47 myelodysplastic/myeloproliferative neoplasm 9.8 KMT2A ETV6
48 myeloproliferative neoplasm 9.8 KMT2A ETV6
49 childhood leukemia 9.8 KMT2A ETV6
50 precursor t-cell acute lymphoblastic leukemia 9.8 KMT2A ETV6

Graphical network of the top 20 diseases related to Ring Chromosome 21:



Diseases related to Ring Chromosome 21

Symptoms & Phenotypes for Ring Chromosome 21

Human phenotypes related to Ring Chromosome 21:

58 31 (show all 35)
# Description HPO Frequency Orphanet Frequency HPO Source Accession
1 abnormal facial shape 58 31 hallmark (90%) Very frequent (99-80%) HP:0001999
2 intellectual disability 58 31 frequent (33%) Frequent (79-30%) HP:0001249
3 eeg abnormality 58 31 frequent (33%) Frequent (79-30%) HP:0002353
4 microcephaly 58 31 frequent (33%) Frequent (79-30%) HP:0000252
5 infertility 58 31 frequent (33%) Frequent (79-30%) HP:0000789
6 psychomotor retardation 58 31 frequent (33%) Frequent (79-30%) HP:0025356
7 amenorrhea 58 31 frequent (33%) Frequent (79-30%) HP:0000141
8 spasticity 58 31 occasional (7.5%) Occasional (29-5%) HP:0001257
9 scoliosis 58 31 occasional (7.5%) Occasional (29-5%) HP:0002650
10 gait disturbance 58 31 occasional (7.5%) Occasional (29-5%) HP:0001288
11 delayed speech and language development 58 31 occasional (7.5%) Occasional (29-5%) HP:0000750
12 short stature 58 31 occasional (7.5%) Occasional (29-5%) HP:0004322
13 diabetes insipidus 58 31 occasional (7.5%) Occasional (29-5%) HP:0000873
14 multiple cafe-au-lait spots 58 31 occasional (7.5%) Occasional (29-5%) HP:0007565
15 holoprosencephaly 58 31 occasional (7.5%) Occasional (29-5%) HP:0001360
16 azoospermia 58 31 occasional (7.5%) Occasional (29-5%) HP:0000027
17 cutaneous photosensitivity 58 31 occasional (7.5%) Occasional (29-5%) HP:0000992
18 small hand 58 31 occasional (7.5%) Occasional (29-5%) HP:0200055
19 narrow palm 58 31 occasional (7.5%) Occasional (29-5%) HP:0004283
20 abnormal heart morphology 58 31 occasional (7.5%) Occasional (29-5%) HP:0001627
21 thoracic hemivertebrae 58 31 occasional (7.5%) Occasional (29-5%) HP:0008467
22 clinodactyly 58 31 occasional (7.5%) Occasional (29-5%) HP:0030084
23 syndactyly 58 31 occasional (7.5%) Occasional (29-5%) HP:0001159
24 fused thoracic vertebrae 58 31 occasional (7.5%) Occasional (29-5%) HP:0030039
25 abnormal thorax morphology 31 occasional (7.5%) HP:0000765
26 decreased circulating antibody level 31 occasional (7.5%) HP:0004313
27 generalized myoclonic seizure 31 occasional (7.5%) HP:0002123
28 bilateral tonic-clonic seizure with generalized onset 31 occasional (7.5%) HP:0025190
29 simple febrile seizure 31 occasional (7.5%) HP:0011171
30 seizures 58 Frequent (79-30%)
31 decreased antibody level in blood 58 Occasional (29-5%)
32 generalized myoclonic seizures 58 Occasional (29-5%)
33 abnormality of the thorax 58 Occasional (29-5%)
34 generalized tonic-clonic seizures without focal onset 58 Occasional (29-5%)
35 simple febrile seizures 58 Occasional (29-5%)

Drugs & Therapeutics for Ring Chromosome 21

Search Clinical Trials , NIH Clinical Center for Ring Chromosome 21

Genetic Tests for Ring Chromosome 21

Genetic tests related to Ring Chromosome 21:

# Genetic test Affiliating Genes
1 Ring Chromosome 21 29

Anatomical Context for Ring Chromosome 21

MalaCards organs/tissues related to Ring Chromosome 21:

40
Heart, Myeloid

Publications for Ring Chromosome 21

Articles related to Ring Chromosome 21:

(show top 50) (show all 75)
# Title Authors PMID Year
1
Prenatal diagnosis and molecular cytogenetic characterization of a pure ring chromosome 21 with a 4.657-Mb 21q22.3 deletion. 61
33494993 2021
2
A Revisited Diagnosis of Collagen VI Related Muscular Dystrophy in a Patient with a Novel COL6A2 Variant and 21q22.3 Deletion. 61
32663882 2020
3
[Alopecia, deformed ear and mental retardation associated with terminal 21q deletion]. 61
30922549 2019
4
Thrombocytopenia and Predisposition to Acute Myeloid Leukemia due to Mosaic Ring 21 with Loss of RUNX1: Cytogenetic and Molecular Characterization. 61
30800047 2019
5
Unexpected Coexistence of a Derivative t(21;21) and Complementary Mosaic r(21) in a Female with Multiple Miscarriages. 61
31195399 2019
6
Combined Immunodeficiency with Ring Chromosome 21. 61
29656336 2018
7
RUNX1 amplification in AML with myelodysplasia-related changes and ring 21 chromosomes. 61
26947932 2017
8
Ring chromosome 21 and monosomy 21 mosaicism in a patient with azoospermia. 61
24471893 2015
9
Monosomy 21 seen in live born is unlikely to represent true monosomy 21: a case report and review of the literature. 61
24649383 2014
10
WITHDRAWN: Corrigendum to "Ring chromosome 21 presenting with sacrococcygeal teratoma: Prenatal diagnosis, molecular cytogenetic characterization and literature review" [Gene 522 (2013) 111-116]. 61
24412089 2013
11
Ring chromosome 21 presenting with sacrococcygeal teratoma: prenatal diagnosis, molecular cytogenetic characterization and literature review. 61
23545316 2013
12
Agminated lentiginosis in a patient with ring chromosome 21. 61
23178995 2012
13
Ring chromosome 21 in the differential diagnosis of waddling gait. 61
22209335 2012
14
Mosaic ring chromosome 21, monosomy 21, and isodicentric ring chromosome 21: prenatal diagnosis, molecular cytogenetic characterization, and association with 2-Mb deletion of 21q21.1-q21.2 and 5-Mb deletion of 21q22.3. 61
22482972 2012
15
Unique genomic structure and distinct mitotic behavior of ring chromosome 21 in two unrelated cases. 61
22398511 2012
16
A de novo supernumerary genomic discontinuous ring chromosome 21 in a child with mild intellectual disability. 61
21574245 2011
17
Inheritance of a Ring Chromosome 21 in a Couple Undergoing In Vitro Fertilization (IVF): A Case Report. 61
23074672 2011
18
An adult female patient with ring chromosome 21: behavioural phenotype and results of high-resolution molecular characterisation. 61
25385124 2010
19
A fetus with ring chromosome 21 characterized by aCGH shows no clinical findings after birth. 61
20509162 2010
20
Atypical Down syndrome phenotype in a girl with 21;21 translocation trisomy. 61
20420031 2010
21
Rare chromosomal complement of trisomy 21 in a boy conceived by IVF and cryopreservation. 61
19778489 2009
22
Sperm chromosome analysis of an infertile patient with a 95% mosaic r(21) karyotype and normal phenotype. 61
19135661 2009
23
Videoendoscopic rehabilitation of iatrogenous Stensen-duct-acquired atresia in a patient with ring chromosome 21 syndrome and drooling. 61
18970914 2008
24
Ring chromosome 21 and reproductive pattern: a familial case and review of the literature. 61
18371955 2008
25
Partial monosomy 7q34-qter and 21pter-q22.13 due to cryptic unbalanced translocation t(7;21) but not monosomy of the whole chromosome 21: a case report plus review of the literature. 61
18564437 2008
26
[Clinical investigation of infertile males with chromosomal anomalies]. 61
17352156 2007
27
[Cytogenetic analysis and phenotype location analysis on the karyotype of a ring chromosome 21 syndrome]. 61
16331572 2005
28
Duplication of the Down syndrome critical region does not predict facial phenotype in a baby with a ring chromosome 21. 61
16155419 2005
29
Dilated ascending aorta in a child with ring chromosome 21 syndrome. 61
15372526 2004
30
Dystonia in a patient with ring chromosome 21. 61
14673898 2003
31
Chromosomal changes detected by fluorescence in situ hybridization in patients with acute lymphoblastic leukemia. 61
14527352 2003
32
Ring chromosome 21 in a boy and a derivative chromosome 21 in the mother: implication for ring chromosome formation. 61
12116206 2002
33
Atypical Down syndrome phenotype with severe developmental delay, hypertonia, and seizures in a child with translocation trisomy 21. 61
11811653 2002
34
Familial gonadotropin-releasing hormone resistance and hypogonadotropic hypogonadism in a family with multiple affected individuals. 61
11384641 2001
35
Amplification of the AML1(CBFA2) gene on ring chromosomes in a patient with acute myeloid leukemia and a constitutional ring chromosome 21. 61
11165321 2001
36
Molecular characterisation of partial chromosome 21 aneuploidies by fluorescent PCR. 61
10507727 1999
37
Hypogammaglobulinaemia in a patient with ring chromosome 21. 61
9370908 1997
38
Characterization of a ring chromosome 21 by FISH-technique. 61
8591669 1995
39
Prenatal diagnosis of familial ring 21 chromosome. 61
7784385 1995
40
"Compensatory" uniparental disomy of chromosome 21 in two cases. 61
7966190 1994
41
[Ring chromosome 21 as a cause of developmental disorder. A case report from the practice of child psychiatry]. 61
7507604 1994
42
Lens dislocation and optic nerve hypoplasia in ring chromosome 21 mosaicism. 61
7847798 1994
43
Unbalanced translocation, t(18;21), detected by fluorescence in situ hybridization (FISH) in a child with 18q- syndrome and a ring chromosome 21. 61
8362906 1993
44
Mechanisms of ring chromosome formation in 11 cases of human ring chromosome 21. 61
1346075 1992
45
Stable ring chromosome 21: molecular and clinical definition of the lesion. 61
1308361 1992
46
Maternal transmission of ring chromosome 21. 61
2253944 1990
47
Holoprosencephaly in an infant with a minute deletion of chromosome 21(q22.3). 61
2363428 1990
48
Ring chromosome 21 transmitted from mother to daughter: its stability in a lymphoblastoid cell line. 61
2369070 1990
49
Dysfunction of chromosomal loop attachment sites: illegitimate recombination linked to matrix association regions and topoisomerase II. 61
2546156 1989
50
Molecular mechanism in the formation of a human ring chromosome 21. 61
2648387 1989

Variations for Ring Chromosome 21

Expression for Ring Chromosome 21

Search GEO for disease gene expression data for Ring Chromosome 21.

Pathways for Ring Chromosome 21

Pathways related to Ring Chromosome 21 according to GeneCards Suite gene sharing:

# Super pathways Score Top Affiliating Genes
1 10.91 KMT2A ETV6

GO Terms for Ring Chromosome 21

Sources for Ring Chromosome 21

3 CDC
7 CNVD
9 Cosmic
10 dbSNP
11 DGIdb
17 EFO
18 ExPASy
19 FMA
20 GARD
28 GO
29 GTR
30 HMDB
31 HPO
32 ICD10
33 ICD10 via Orphanet
34 ICD9CM
35 IUPHAR
36 KEGG
37 LifeMap
39 LOVD
41 MedGen
44 MeSH
45 MESH via Orphanet
46 MGI
49 NCI
50 NCIt
51 NDF-RT
53 NINDS
54 Novoseek
56 OMIM via Orphanet
57 OMIM® (Updated 05-Apr-2021)
61 PubMed
63 QIAGEN
68 SNOMED-CT via HPO
69 Tocris
70 UMLS
71 UMLS via Orphanet
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