Chromosome Deletion Syndromes List
Chromosome deletion syndromes are caused by deletions from parts of chromosomes. This means that parts of a chromosome are missing as a result of the deletion.
Also known as chromosomal abnormalities these deletions can cause serious medical and health issues from birth. They can also cause severe intellectual disability.
Chromosomal deletion abnormalities, including some of the main chromosome diseases, may be identified by prenatal genetic screening and testing. They can also be diagnosed following birth, either by a type of genetic testing known as karyotyping and by the presence of specific symptoms or unique facial features.
The type of testing will be determined by the size of the deletion. A larger deletion will often require karyotyping (a type of genetic testing), but in other examples fluorescent in situ hybridization or microarray analysis (types of genetic testing) may be used.
The size of the deletion on the chromosome may also determine the severity of symptoms an individual experiences, and the specific symptoms they present with.
Chromosome deletion syndromes list
Cri-du-chat syndrome (5p- (5p minus) syndrome)
This chromosome deletion syndrome is characterized by its high pitched cat-like cry that is often identified at birth. Other main symptoms of this condition include intellectual disability coupled with significant developmental delay and unique facial features.
The syndrome is caused when there is a deletion on chromosome 5, i.e. a missing piece. This syndrome is not inherited and is always the result of a new deletion.
Wolf-Hirschhorn syndrome (4p- (4p minus) syndrome)
This chromosome deletion syndrome is characterized by its very distinct and unique facial features. Delayed or slow physical growth is also very common and a main symptom.
The syndrome is caused when there is a deletion on chromosome 4, i.e. a missing piece. This syndrome is not usually inherited and is generally the result of a new deletion.
This chromosome deletion syndrome is characterized by childhood obesity which can be life-threatening if not addressed. This rare disease triggers an insatiable appetite in those affected which in turn leads to chronic overeating.
Prader-Willi is caused in 70% of cases when there is a deletion on the paternal (father’s copy) of chromosome 15. In 25% of cases this chromosome deletion occurs on the maternal (mother’s copy) of chromosome 15. In the remaining cases the cause of the syndrome is known as translocation between both the maternal and paternal copies of chromosome 15.
The diagnosis of chromosomal deletion syndrome may be a difficult process. It is important that anyone undergoing diagnosis for a rare disease, either in themselves or a family member, should consult with a genetic counselor before embarking on the diagnosis and testing process.