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Recombinant 8 syndrome
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Condition

Recombinant 8 syndrome

Recombinant 8 syndrome is a rare genetic condition characterized by complex congenital heart abnormalities, intellectual disability, abnormal muscle tone, and distinctive facial features, primarily affecting individuals of Hispanic ancestry from a specific region.

Overview

Recombinant 8 syndrome is a condition that involves complex congenital heart abnormalities, skeletal abnormalities, moderate to severe intellectual disability, abnormal muscle tone, and a distinctive facial appearance.

The most common heart abnormalities are known as tetralogy of Fallot and conotruncal defects. The characteristic facial features include a prominent forehead; a broad nasal bridge; 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 hypertrophy), abnormal tooth development, or an opening in the upper lip (cleft lip) with or without an opening in the roof of the mouth (cleft palate). Males with this condition frequently have undescended testes (cryptorchidism). Some affected individuals have recurrent ear infections (otitis media), hearing loss, or hand and finger differences. In individuals with recombinant 8 syndrome, the heart abnormalities can be life-threatening.

Frequency

Recombinant 8 syndrome is a rare condition; its exact incidence is unknown. Most people with this condition are of Hispanic ancestry, particularly from 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.

Causes

Recombinant 8 syndrome is caused by a rearrangement of chromosome 8 that results in deletion of a piece of the short (p) arm and duplication of a piece of the long (q) arm. The deletion and duplication result in the recombinant 8 chromosome. On the recombinant 8 chromosome, there is one copy of each of the genes instead of the usual two on the section of chromosome 8p that is deleted; and there are three copies each of the genes on the section of chromosome 8q that is duplicated. The signs and symptoms of recombinant 8 syndrome are related to the loss and addition of genetic material on these regions of chromosome 8. While the regions affected in recombinant chromosome 8 includes hundreds of genes, researchers are working to determine which genes play a role in the signs and symptoms of this condition.

Learn more about the chromosome associated with Recombinant 8 syndrome

  • chromosome 8

Inheritance

Recombinant 8 syndrome 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 one parent with a change in chromosome 8 called pericentric 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 deleted or duplicated when inversions are passed to the next generation. People with the chromosome 8 inversion are at risk of having a child with recombinant 8 syndrome.

Other Names

  • Rec(8) syndrome
  • Recombinant chromosome 8 syndrome
  • San Luis Valley syndrome

Frequently Asked Questions

Routine audiologic evaluations every 6–12 months are recommended, especially if the child has a history of otitis media. Prophylactic antibiotics may be considered for frequent infections, and tympanostomy tubes can be placed to reduce middle‑ear fluid and improve hearing. Prompt treatment of ear infections is crucial to prevent speech delays and further hearing loss.
Early intervention programs that combine speech therapy, occupational therapy, and specialized education plans are essential. Structured routines, visual schedules, and assistive technology can help maximize learning. Regular developmental assessments allow for timely adjustments to therapy goals and educational strategies.
Tetralogy of Fallot and other conotruncal defects are the hallmark heart abnormalities. Newborns or infants with cyanosis, a harsh systolic murmur, or poor feeding may warrant an echocardiogram within the first weeks of life. Early imaging allows for timely surgical or catheter-based interventions, which can significantly improve long‑term outcomes.
The deletion or rearrangement of specific genes on chromosome 8 disrupts normal craniofacial and neuromuscular development. This leads to characteristic features such as a prominent forehead, broad nasal bridge, and micrognathia, as well as abnormal muscle tone (hypotonia or hypertonia) that can affect motor milestones. Genetic counseling can provide insight into the specific genes involved and their phenotypic impact.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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