2024年8月15日 · Microdeletions, or submicroscopic deletions, are chromosomal deletions that are too small to be detected by light microscopy using conventional cytogenetic methods. Specialized testing is needed to identify these deletions.

Microdeletions are chromosomal abnormalities that can (but don't always) cause health problems. By detecting them in prenatal tests, you can prepare before birth.

A microdeletion syndrome is a syndrome caused by a chromosomal deletion smaller than 5 million base pairs (5 Mb) spanning several genes that is too small to be detected by conventional cytogenetic methods or high resolution karyotyping (2–5 Mb).

Microdeletion and microduplication syndromes are disorders caused by submicroscopic deletions or duplications of contiguous genes on particular parts of chromosomes. Postnatal diagnosis is suspected by clinical appearance and preferably confirmed by chromosomal microarray analysis or by fluorescent in situ hybridization.

The ability to quickly interrogate large cohorts using chromosome microarrays and, more recently, next-generation sequencing has led to the rapid discovery of novel microdeletions and microduplications associated with disease, including very rare but clinically significant rearrangements.

Syndromes involving smaller deletions (and additions) that affect one or more contiguous genes on a chromosome and are not visible on karyotyping are considered microdeletion and duplication syndromes.

Deletions can vary in size, and if a deletion is too small to be seen under a microscope, it is called a microdeletion. We know that our genetic information is stored in DNA , which is then tightly packed into chromosomes , and that genes are made up of stretches of DNA.

Microdeletions and duplications are genetic abnormalities that involve the loss or duplication of a small segment of DNA from a chromosome. Unlike bigger genetic abnormalities like Down syndrome, which involve having an extra copy of an entire chromosome, microdeletions and duplications affect only a tiny portion of genetic material.

All Known Microdeletions and/or Reciprocal Microduplications up to January 2012 by Chromosomes from pter to qter That Are Reported at Least in Two Different Studies or in More Than One Individual.

Microdeletion and microduplication syndromes are disorders caused by submicroscopic deletions or duplications of contiguous genes on particular parts of chromosomes. Postnatal diagnosis is suspected by clinical appearance and preferably confirmed by chromosomal microarray analysis or by fluorescent in situ hybridization.