Recombinant 8 syndrome

Reviewed April 2009

What is recombinant 8 syndrome?

Recombinant 8 syndrome is a condition that involves heart and urinary tract abnormalities, moderate to severe intellectual disability, and a distinctive facial appearance. The characteristic facial features include a wide, square face; a thin upper lip; a downturned mouth; a small chin (micrognathia); wide-set eyes (hypertelorism); and low-set or unusually shaped ears. People with recombinant 8 syndrome may have overgrowth of the gums (gingival hyperplasia) and abnormal tooth development. Males with this condition frequently have undescended testes (cryptorchidism). Some affected individuals have recurrent ear infections (otitis media) or hearing loss. Many children with recombinant 8 syndrome do not survive past early childhood, usually due to complications related to their heart abnormalities.

How common is recombinant 8 syndrome?

Recombinant 8 syndrome is a rare condition; its exact incidence is unknown. Most people with this condition are descended from a Hispanic population originating in the San Luis Valley area of southern Colorado and northern New Mexico. Recombinant 8 syndrome is also called San Luis Valley syndrome. Only a few cases outside this population have been found.

What are the genetic changes related to recombinant 8 syndrome?

Recombinant 8 syndrome is caused by a rearrangement of chromosome 8 that results in a deletion of a piece of the short (p) arm and a duplication of a piece of the long (q) arm. The deletion and duplication result in the recombinant 8 chromosome. The signs and symptoms of recombinant 8 syndrome are related to the loss and addition of genetic material on these regions of chromosome 8. Researchers are working to determine which genes are involved in the deletion and duplication on chromosome 8.

Related Chromosome(s)

Changes involving this chromosome are associated with recombinant 8 syndrome.

chromosome 8

Can recombinant 8 syndrome be inherited?

This condition is inherited in an autosomal dominant pattern, which means one copy of the recombinant chromosome 8 in each cell is sufficient to cause the disorder.

Most people with recombinant 8 syndrome have at least one parent with a change in chromosome 8 called an inversion. An inversion involves the breakage of a chromosome in two places; the resulting piece of DNA is reversed and reinserted into the chromosome. Genetic material is typically not lost as a result of this inversion in chromosome 8, so people usually do not have any related health problems. However, genetic material can be lost or duplicated when inversions are being passed to the next generation. People with this chromosome 8 inversion are at of risk having a child with recombinant 8 syndrome.

Where can I find information about diagnosis or management of recombinant 8 syndrome?

These resources address the diagnosis or management of recombinant 8 syndrome and may include treatment providers.

Genetic Testing Registry: Recombinant chromosome 8 syndrome (http://www.ncbi.nlm.nih.gov/gtr/conditions/C0795822)

You might also find information on the diagnosis or management of recombinant 8 syndrome in Educational resources (http://www.ghr.nlm.nih.gov/condition/recombinant-8-syndrome/show/Educational+resources) and Patient support (http://www.ghr.nlm.nih.gov/condition/recombinant-8-syndrome/show/Patient+support).

General information about the diagnosis (http://ghr.nlm.nih.gov/handbook/consult/diagnosis) and management (http://ghr.nlm.nih.gov/handbook/consult/treatment) of genetic conditions is available in the Handbook. Read more about genetic testing (http://ghr.nlm.nih.gov/handbook/testing), particularly the difference between clinical tests and research tests (http://ghr.nlm.nih.gov/handbook/testing/researchtesting).

To locate a healthcare provider, see How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

Where can I find additional information about recombinant 8 syndrome?

You may find the following resources about recombinant 8 syndrome helpful. These materials are written for the general public.

MedlinePlus - Health information
- Health Topic: Congenital Heart Defects (http://www.nlm.nih.gov/medlineplus/congenitalheartdefects.html)
- Health Topic: Tooth Disorders (http://www.nlm.nih.gov/medlineplus/toothdisorders.html)
Genetic and Rare Diseases Information Center - Information about genetic conditions and rare diseases (http://rarediseases.info.nih.gov/gard/9698/resources/resources/1)
Educational resources - Information pages
Orphanet (http://www.orpha.net/consor/cgi-bin/OC_Exp.php?Lng=EN&Expert=96167)
Patient support - For patients and families
- Chromosome Disorder Outreach (http://www.chromodisorder.org/CDO/)
- Unique: Rare Chromosome Disorder Support Group (http://www.rarechromo.org/html/home.asp)

You may also be interested in these resources, which are designed for healthcare professionals and researchers.

Genetic Testing Registry - Repository of genetic test information
- Genetic Testing Registry: Recombinant chromosome 8 syndrome (http://www.ncbi.nlm.nih.gov/gtr/conditions/C0795822)
PubMed - Recent literature (http://www.ncbi.nlm.nih.gov/pubmed?term=((recombinant%208%20syndrome%5BTIAB%5D)%20OR%20(recombinant%20chromosome%208%20syndrome%5BTIAB%5D)%20OR%20(rec%208%20syndrome%5BTIAB%5D))%20AND%20english%5Bla%5D%20AND%20human%5Bmh%5D)
OMIM - Genetic disorder catalog (http://omim.org/entry/179613)

What other names do people use for recombinant 8 syndrome?

rec(8) syndrome
recombinant chromosome 8 syndrome
San Luis Valley syndrome

For more information about naming genetic conditions, see the Genetics Home Reference Condition Naming Guidelines (http://ghr.nlm.nih.gov/ConditionNameGuide) and How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.

What if I still have specific questions about recombinant 8 syndrome?

Ask the Genetic and Rare Diseases Information Center (http://rarediseases.info.nih.gov/GARD/).

What glossary definitions help with understanding recombinant 8 syndrome?

autosomal ; autosomal dominant ; cell ; chromosome ; cryptorchidism ; deletion ; DNA ; duplication ; gingival ; gums ; hyperplasia ; hypertelorism ; incidence ; inversion ; micrognathia ; otitis media ; population ; rearrangement ; syndrome ; testes

You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://www.ghr.nlm.nih.gov/glossary).

References

Graw SL, Sample T, Bleskan J, Sujansky E, Patterson D. Cloning, sequencing, and analysis of inv8 chromosome breakpoints associated with recombinant 8 syndrome. Am J Hum Genet. 2000 Mar;66(3):1138-44. (http://www.ncbi.nlm.nih.gov/pubmed/10712224?dopt=Abstract)
Smith AC, Spuhler K, Williams TM, McConnell T, Sujansky E, Robinson A. Genetic risk for recombinant 8 syndrome and the transmission rate of balanced inversion 8 in the Hispanic population of the southwestern United States. Am J Hum Genet. 1987 Dec;41(6):1083-103. (http://www.ncbi.nlm.nih.gov/pubmed/3687942?dopt=Abstract)
Sujansky E, Smith AC, Prescott KE, Freehauf CL, Clericuzio C, Robinson A. Natural history of the recombinant (8) syndrome. Am J Med Genet. 1993 Sep 15;47(4):512-25. (http://www.ncbi.nlm.nih.gov/pubmed/8256815?dopt=Abstract)
Williams TM, McConnell TS, Martinez F Jr, Smith AC, Sujansky E. Clinicopathologic and dysmorphic findings in recombinant chromosome 8 syndrome. Hum Pathol. 1984 Nov;15(11):1080-4. (http://www.ncbi.nlm.nih.gov/pubmed/6490002?dopt=Abstract)

The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.