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Genetic and Rare Diseases Information Center (GARD)

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22q11.2 deletion syndrome


Other Names for this Disease

  • Autosomal dominant Opitz G/BBB syndrome
  • CATCH22
  • Cayler cardiofacial syndrome
  • Chromosome 22q11.2 deletion syndrome
  • Conotruncal anomaly face syndrome
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Your Question

I am confused with some articles on types of DiGeorge syndrome: What is complete vs partial DiGeorge syndrome? Is there any difference regarding heterozyous / homozygous deletion?

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

What is 'complete' versus 'partial' DiGeorge syndrome?

DiGeorge syndrome was once thought to be a distinct syndrome, but is now recognized to fall within the disorder spectrum known as 22q11.2 deletion syndrome. Symptoms of what was formerly known as DiGeorge syndrome were variable and the underlying cause (deletions of 22q11.2) is also responsible for related/overlapping syndromes. Terms such as 'complete' and 'partial' DiGeorge syndrome have been used in reference to individual cases which had all the characteristic signs and symptoms (e.g., hypoparathyroidism, absent thymus, and congenital heart disease) verses those with only some of them.[1]
Last updated: 10/28/2013

Is there any difference between having the 22q11.2 deletion on one (heterozygous) versus both (homozygous) copies of chromosome 22?

Most people with 22q11.2 deletion syndrome are missing a sequence of about 3 million DNA building blocks (base pairs) on one copy of chromosome 22 in each cell. This region contains 30 to 40 genes, many of which have not been well characterized. A small percentage of affected individuals have shorter deletions in the same region.[2] We are unaware of any cases of homozygous 22q11.2 deletions. However, in addition to the loss of genes in the 22q11.2 region (e.g., TBX1 and COMT), the highly variable signs and symptoms of 22q11.2 deletion syndrome are in part due to changes outside the deleted region or on the remaning (non-deleted) copy of chromosome 22 (e.g., SNAP29).[2][3][4]
Last updated: 10/28/2013

References
Other Names for this Disease
  • Autosomal dominant Opitz G/BBB syndrome
  • CATCH22
  • Cayler cardiofacial syndrome
  • Chromosome 22q11.2 deletion syndrome
  • Conotruncal anomaly face syndrome
See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.