Microdeletion syndrome

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).^[1][2] Detection is done by fluorescence in situ hybridization (FISH). Larger chromosomal deletion syndromes are detectable using karyotyping techniques.

Twins in Poland with 22q11 microdeletion syndrome

Examples

• DiGeorge syndrome or velocardiofacial syndrome^[3] – most common microdeletion syndrome
• Prader–Willi syndrome^[4][5]
• Angelman syndrome^[4]
• Neurofibromatosis type I^[6]
• Neurofibromatosis type II^[7][8]
• Williams syndrome^[9]
• Miller–Dieker syndrome^[10]
• Smith–Magenis syndrome^[11]
• Rubinstein–Taybi syndrome^[12]
• Wolf–Hirschhorn syndrome^[13]