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~3130 cases included
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How to cite this database:
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last update: 25. Jan 2026 |
Created by Dr.
Thomas Liehr (PhD) |
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link
helpful for diagnostics
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References
Collect all cases of constitutional human ring chromosomes in infertile and mentally retarded.
Thoughts on formation mechanisms of ring chromosomes see Refs {1, 144}.
RCs and tumor predisposition see Ref {591}.
Work of international consortium for human ring chromosomes see {1182}.
Ring chromosome as research tool for chromosome therapy see {1183-1187}.
1 RC case among 16750 cases in {1683}
Acc. to {1479} who studied 40 prenatal and 133 postnatal RC cases male to female ratio was 70:103.
23/40 fetuses (57.5%) were found with abnormal results in sonography (12/40 cases = 30%) and/ or other non-invasive tests.
48/133 postnatal cases (36.1%) had growth retardation; 15 (11.3%) had DD.
7/92 tested cases were familial.
RC-X: 43/173 (~25% - here not distinguished lareg and small RCs)
RC-13: 17/173 (~10%)
RC from an acrocentric: 44/133 (~25%)
The remainder RCs are mentioned as "RCs of unknown chromosomal origin" -
suggesting authors report on sSMCs?
The decline in cytogenetic analyses hampers diagnoses of ring chromosomes as highlighted in 2025 here.
This page is organized like the 'sister-page' on small supernumerary marker chromosomes (sSMC)
- the structure is explained here.
Also take care that the nomenclature here may not always be done exactly acc. to ISCN !!
Patient support groups related to ring chromosomes
UNIQUE = rare chromosome disorder support group: http://www.rarechromo.org/
Email: info@rarechromo.org
Helpline: +44(0)1883 723356
UNIQUE has contact ring chromosome families.
Ring chromosome specific support groups:
Ring Chromosome 8
Facebook group: Life With Ring Chromosome 8
https://www.facebook.com/ringchromo8/
Ring Chromosome 14
Ring14 international
https://www.ring14.org
Living with Ring14
https://ring14usa.com/index.php/2020/05/14/living-with-ring14/
Ring Chromosome 18
Ring Chromosome 18, The Chromosome 18 Registry & Research Society
https://www.chromosome18.org/
Facebook group: C18 Registry Ring 18
https://www.facebook.com/groups/1694569320575824/
Ring Chromosome 20
Ring20 Research and support UK CIO Registered Charity Number 1165651 (England and Wales) SC048893 (Scotland)
https://ring20researchsupport.co.uk/
Facebook group: Ring20 Research & Support UK CIO
https://www.facebook.com/Ring20ResearchandSupportUK/
Ring Chromosome 22
Facebook group: Ring Chromosome 22
https://www.facebook.com/groups/ring22/
Phelan-McDermid Syndrome Foundation
https://pmsf.org/document/chromosome-22-ring/
Other support groups for genetic disorders including ring chromsomes
CONTACT a family - for families with disabled children
https://contact.org.uk/
LEONA - Verein für Eltern chromosomal geschädigter Kinder e.V. (German site)
http://www.leona-ev.de/
Living with Trisomy
http://www.LivingWithTrisomy.org
Valentin APAC
http://www.valentin-apac.org
Chromosome Disorder Outreach (CDO)
http://www.chromodisorder.org
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