Microdeletion syndrome: Difference between revisions

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'''Microdeletion syndrome''' is a genetic condition that results from the deletion of several genes on a chromosome. This condition is also known as a [[Chromosome deletion|chromosomal deletion]] or a [[Partial monosomy|partial monosomy]].
== Microdeletion Syndrome ==


== Overview ==
[[File:Jedyne_w_Polsce_bliźniaki_z_zespołem_mikrodelecji_22q11.jpg|thumb|right|Children with 22q11.2 microdeletion syndrome]]


Microdeletion syndromes are caused by submicroscopic deletions in the DNA sequence that are too small to be detected by conventional cytogenetic methods. These deletions can occur in any part of the genome and can affect any number of genes. The clinical manifestations of microdeletion syndromes are highly variable and depend on the specific genes that are deleted.
'''Microdeletion syndrome''' refers to a group of genetic disorders caused by the deletion of a small segment of a chromosome. These deletions are typically too small to be detected by conventional [[karyotyping]] and often require more sensitive techniques such as [[fluorescence in situ hybridization]] (FISH) or [[comparative genomic hybridization]] (CGH) for diagnosis.


== Causes ==
== Characteristics ==
Microdeletion syndromes can result in a wide range of clinical features, depending on the specific genes that are deleted. Common characteristics may include developmental delays, intellectual disabilities, distinctive facial features, and congenital anomalies. The severity and specific symptoms can vary widely even among individuals with the same microdeletion.


Microdeletion syndromes are typically caused by [[Non-allelic homologous recombination|non-allelic homologous recombination]] (NAHR) during meiosis. NAHR is a type of genetic recombination that occurs between two sequences of DNA that are similar but not identical. This can lead to the deletion of the DNA sequence between the two homologous sequences.
== Common Microdeletion Syndromes ==


== Diagnosis ==
=== 22q11.2 Deletion Syndrome ===
The 22q11.2 deletion syndrome, also known as [[DiGeorge syndrome]] or velocardiofacial syndrome, is one of the most common microdeletion syndromes. It is caused by the deletion of a small segment of chromosome 22 and can lead to heart defects, immune deficiencies, and characteristic facial features.
 
=== Williams Syndrome ===
[[Williams syndrome]] is caused by a deletion on chromosome 7q11.23. It is characterized by cardiovascular disease, distinctive facial features, and a unique cognitive profile with strengths in verbal short-term memory and language.


Diagnosis of microdeletion syndromes is typically made through [[Genetic testing|genetic testing]]. This can include [[Karyotyping|karyotyping]], [[Fluorescence in situ hybridization|fluorescence in situ hybridization]] (FISH), and [[Comparative genomic hybridization|comparative genomic hybridization]] (CGH). More recently, [[Next-generation sequencing|next-generation sequencing]] (NGS) technologies have been used to diagnose microdeletion syndromes.
=== Prader-Willi Syndrome ===
[[Prader-Willi syndrome]] is associated with a deletion on chromosome 15q11-q13. It is characterized by hypotonia, obesity, intellectual disability, and hypogonadism.


== Treatment ==
=== Angelman Syndrome ===
[[Angelman syndrome]] results from a deletion on chromosome 15q11-q13, similar to Prader-Willi syndrome, but involves different genes. It is characterized by severe intellectual disability, lack of speech, and a happy demeanor.


There is currently no cure for microdeletion syndromes. Treatment is typically supportive and focuses on managing the symptoms of the condition. This can include physical therapy, occupational therapy, speech therapy, and educational support. In some cases, medication may be used to manage specific symptoms.
== Diagnosis ==
Diagnosis of microdeletion syndromes often involves genetic testing techniques such as FISH, CGH, or [[next-generation sequencing]]. These tests can identify the specific chromosomal deletions responsible for the syndrome.


== See also ==
== Management ==
Management of microdeletion syndromes is typically multidisciplinary, involving specialists in genetics, cardiology, neurology, and other fields as needed. Treatment focuses on addressing the specific symptoms and complications associated with the syndrome.


== Related Pages ==
* [[Chromosomal deletion]]
* [[Genetic disorder]]
* [[Genetic disorder]]
* [[Chromosome abnormality]]
* [[Fluorescence in situ hybridization]]
* [[Genomic disorder]]
* [[Comparative genomic hybridization]]
* [[Copy-number variation]]


[[Category:Genetic disorders]]
[[Category:Genetic disorders]]
[[Category:Chromosome abnormalities]]
[[Category:Chromosomal abnormalities]]
[[Category:Syndromes]]
{{Genetic disorder}}
{{Chromosome abnormalities}}
[[Category:Syndromes]] {{stub}}

Latest revision as of 14:19, 21 February 2025

Microdeletion Syndrome[edit]

File:Jedyne w Polsce bliźniaki z zespołem mikrodelecji 22q11.jpg
Children with 22q11.2 microdeletion syndrome

Microdeletion syndrome refers to a group of genetic disorders caused by the deletion of a small segment of a chromosome. These deletions are typically too small to be detected by conventional karyotyping and often require more sensitive techniques such as fluorescence in situ hybridization (FISH) or comparative genomic hybridization (CGH) for diagnosis.

Characteristics[edit]

Microdeletion syndromes can result in a wide range of clinical features, depending on the specific genes that are deleted. Common characteristics may include developmental delays, intellectual disabilities, distinctive facial features, and congenital anomalies. The severity and specific symptoms can vary widely even among individuals with the same microdeletion.

Common Microdeletion Syndromes[edit]

22q11.2 Deletion Syndrome[edit]

The 22q11.2 deletion syndrome, also known as DiGeorge syndrome or velocardiofacial syndrome, is one of the most common microdeletion syndromes. It is caused by the deletion of a small segment of chromosome 22 and can lead to heart defects, immune deficiencies, and characteristic facial features.

Williams Syndrome[edit]

Williams syndrome is caused by a deletion on chromosome 7q11.23. It is characterized by cardiovascular disease, distinctive facial features, and a unique cognitive profile with strengths in verbal short-term memory and language.

Prader-Willi Syndrome[edit]

Prader-Willi syndrome is associated with a deletion on chromosome 15q11-q13. It is characterized by hypotonia, obesity, intellectual disability, and hypogonadism.

Angelman Syndrome[edit]

Angelman syndrome results from a deletion on chromosome 15q11-q13, similar to Prader-Willi syndrome, but involves different genes. It is characterized by severe intellectual disability, lack of speech, and a happy demeanor.

Diagnosis[edit]

Diagnosis of microdeletion syndromes often involves genetic testing techniques such as FISH, CGH, or next-generation sequencing. These tests can identify the specific chromosomal deletions responsible for the syndrome.

Management[edit]

Management of microdeletion syndromes is typically multidisciplinary, involving specialists in genetics, cardiology, neurology, and other fields as needed. Treatment focuses on addressing the specific symptoms and complications associated with the syndrome.

Related Pages[edit]