What is the cause of microdeletion syndrome?
1 microdeletion syndrome is caused by the loss of a small piece of one copy of chromosome 2, one of the 23 pairs of chromosomes in each cell in our body. Losing this small piece of chromosome 2 means that people with this microdeletion are missing one copy of the gene called MBD5.
How do chromosomal microdeletions occur?
A microdeletion is an abnormality that occurs when a piece of a chromosome is missing. In fact, it’s just what it sounds like: micro (tiny); deletion (taken away). You might remember from high school biology that virtually all of our cells contain chromosomes with DNA; we get 23 from each parent for a total of 46.
What does chromosome 22 indicate?
Sequencing and mapping efforts have already revealed that chromosome 22 is implicated in the workings of the immune system, congenital heart disease, schizophrenia, mental retardation, birth defects, and several cancers including leukemia.
How common are Microdeletions?
Microdeletions are mostly spontaneous and occur in approximately 5% of patients with unexplained mental retardation [2,3]. They are frequently associated with multiple congenital anomalies and developmental delay [4,5]. The most common microdeletion syndromes are DiGeorge syndrome (22q11.
Are Microdeletions inherited?
1 microdeletion is inherited in an autosomal dominant pattern, which means that missing genetic material from one of the two copies of chromosome 1 in each cell is sufficient to increase the risk of delayed development, intellectual disability, and other signs and symptoms.
What mutation is chromosome 22?
DiGeorge syndrome, more accurately known by a broader term — 22q11. 2 deletion syndrome — is a disorder caused when a small part of chromosome 22 is missing. This deletion results in the poor development of several body systems.
How are Microdeletions diagnosed?
The diagnosis is made by fluorescent in situ hybridization (FISH) or comparative genetic hybridization (CGH). The prevalence of patients with the phenotypic diagnosis of 22q11DS who are positive for the deletion is 68% to 81%. 22q11DS is transmitted as an autosomal-dominant trait, but most cases are de novo deletions.
Are Microdeletions common?
Some microdeletion syndromes are very rare, while others are more common such as DiGeorge syndrome, Prader-Willi syndrome, Angelman syndrome, Williams syndrome, and Wolf-Hirschhorn syndrome.