Below is a summary for 17q21.31 deletion syndrome or Koolen-de Vries syndrome observed in research publications. This is not meant to take the place of medical advice.
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What is 17q21.31 deletion syndrome or Koolen-de Vries syndrome?
17q21.31 deletion syndrome happens when a person is missing a piece of chromosome 17, one of the body’s 46 chromosomes. Chromosomes are structures in our cells that house our genes. The missing piece can affect learning and how the body develops.
17q21.31 deletion syndrome is also called Koolen-de Vries syndrome. This condition is caused by a deletion in the KANSL1 gene, which is missing when a person has a 17q21.31 deletion .
Because the 17q21.31 region is important for the proper function of the body’s cells, some people may have:
- Developmental delay
- Intellectual disability
- Low muscle tone
- Undescended testicles in males
- Heart or kidneys defects
- Language issues and nasal voice
- Very social behavior
- Feeding difficulty
- Brain changes seen on magnetic resonance imaging (MRI)
- Hip dislocation
- Overly flexible joints
- Rounding of the upper back
- Sideways curvature of the spine, also called scoliosis
Do people who have 17q21.31 deletion syndrome look different?
People with 17q21.31 deletion syndrome may look different. Appearance can vary and can include some but not all of these features:
- Long face
- Pear-shaped nose with a round tip
- Large ears
- Opening between the eyelids that is narrow or slants upward
- Drooping eyelids
- A skin fold covering the inner corner of the eye
- High forehead
- Unusual hair texture
- Smaller than average teeth size
- Fewer number of teeth than average
- Smaller than average head size
- Short height
How many people have 17q21.31 deletion syndrome?
As of 2021, at least 100 children and adults with 17q21.31 deletion syndrome have been described in medical research. The oldest person known to date is 63 years old.
Research Article Summaries