What Are Related Disorders?

Currently, approximately 25% of SOFT's family membership consists of parents whose child does not (or did not) have full trisomy 18 or 13.  Mosaicism, partial trisomy, translocations and other related chromosomal disorders are variable phenotypes of a full trisomy. Full trisomy refers to three copies of a chromosome being present in all cells. Mosaic trisomy refers to two cell lines in a person; one with trisomy (3 copies of a chromosome), the other with 2 copies.  Partial trisomy occurs when only a piece of a chromosome is extra in a person's cells due to translocation (the attachment of part of one chromosome to another).

In trisomy 13, translocation and mosaicism occur in about 20% of cases (Carey, Trisomy 13 Facts (2015) www.trisomy.org ).  In trisomy 18, less than 5% have mosaicism and about 2% partial trisomy (Cereda and Carey. 2012, The Trisomy 18 Syndrome).   A variable phenotype results in a wider range of outcomes; generally more optimistic, though some might be as affected as a child with a full trisomy.   Retesting for mosaicism is sometimes suggested for a child with a full trisomy diagnosis, who is doing better than predicted.  Survival statistics for full trisomy are generally not applicable to variable phenotypes.

Studies of groups of individuals with rare disorders are hampered by their small numbers or uniqueness, but there might be case studies for some.   The NIH Genetic and Rare Disease Information Center provides information about some disorders at: https://rarediseases.info.nih.gov/. The National Organization for Rare Disorders (NORD) has a search page for rare disorders at:

Support Groups

Related Chromosome Disorder Groups:


Chromosome 3q

Chromosome 3q Disorder Registry family information and support
Website: chromosome3disorder.com/

4P- Support Group (Wolf-Hirshorn Syndrome)

Website: www.4p-supportgroup.org
Wolf-Hirshhorn Syndrome, Deletion 4P, A Guidebook for Families , Schaefer et al,  1996
Christine Kleimola, SOFT member, initiated and helped write this book.
Ypsilanti, MI
Phone: 734-482-4027
Email: chriskleimola@sbcglobal.net

Chromosome 8

Judy Miller
Coralville, IA
Phone: 319-337-2608
Email: Vamjam1@mchsi.com

Trisomy 9, Trisomy 9 Mosaic

(9TIPS) Trisomy 9  International Parent Support Group
9TIPS is an international support group for trisomy 9, covering all variations.
Website: www.trisomy9.org/9tips.htm
Alice Todd
Highland, CA
Phone: (909) 862-4470
Email:  BTODD@roadrunner.com

Trisomy 10

Distal Trisomy 10q Families support group
Website: trisomy10q.org
Email: info@trismoy10q.org

Trisomy 14

Website: www.facebook.com/Trisomy14awareness

Chromosome 22

Chromosome 22 Central
Website: www.c22c.org
Stephanie St Pierre
Timmons, Ontario, Canada
Phone:  (705) 268-3099

Smith/Lemli/Opitz Syndrome (SLOS)
Margaret and Jim Thompson
Richardson, Tx
Phone: (972) 234-8788
Email: jmgthompson@att.net

National Organization for Rare Disorders (NORD) a 501(c)(3) organization, is a unique federation of voluntary health organizations dedicated to helping people with rare "orphan" diseases.
Website: www.rarediseases.org

Office of Rare Disorders at the National Institutes of Health, at: rarediseases.info.nih.gov/

Genetic and Rare Diseases Information Center (GARD) rarediseases.info.nih.gov/GARD/

DiseaseInfoSearch, for information on specific genetic conditions, at: www.geneticalliance.org/

Support Groups for Chromosomal Conditions:  Contact information for many specific disorder support groups.   www.kumc.edu/gec/support/chromoso.html

The Children's Rare Disease Network, at: www.crdnetwork.org/

The Rare Blog, at: www.crdnetwork.org/blog/

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