Chromosomes are genetic material and the carriers of genes. The human body has 23 pairs of chromosomes, with 22 pairs being common to both sexes and called autosomes. The other pair determines sex and is called the sex chromosomes, which differ between males (XY) and females (XX). In reproductive cells, male cells consist of 22 autosomes plus Y, while female cells consist of 22 autosomes plus X.
Introduction to chromosomal microarray analysis
Chromosomal microarray analysis (CMA) is a high-resolution, high-throughput technique that uses specific nucleic acid probes to detect copy number variations in the entire genome of a chromosome. It is particularly advantageous in the diagnosis of chromosomal microdeletion and microduplication syndromes, and has significantly higher resolution than traditional karyotype analysis. CMA is a precise and fast chromosome analysis technology.
The technique not only effectively detects copy number variations, but also can detect most cases of uniparental disomy (UPD) and triploidy, as well as to a certain extent mosaicism. A chip design that covers both CNV and SNP detection probes can possess features of both CNV and SNP chips simultaneously.
Reasons for performing chromosomal microarray analysis
Those who undergo high-resolution chromosome examination to reduce pregnancy risks due to microdeletion or microduplication. Even though some congenital diseases cannot be detected with traditional chromosome and ultrasound examinations, chromosomal microarray analysis can exclude the possibility of these problems.
Cases where an abnormality has been found in traditional chromosome examination, but the exact location cannot be determined, and it is unclear whether it affects key genes.
Cases where the fetus shows structural abnormalities in ultrasound examinations, but chromosome examination is normal.
Those with a family history of congenital abnormalities or those who have already given birth to babies with congenital abnormalities, but the cause cannot be found with traditional chromosome examination. Chromosomal microarray analysis, in combination with traditional karyotype analysis, can identify chromosomal microdeletions and microduplications that cannot be differentiated macroscopically, providing strong evidence for clinical diagnosis.
Clinical application of chromosomal microarray analysis
Clinical applications in the prevention and control of birth defects: genetic testing for recurrent miscarriage and stillbirth; etiological testing for those who have given birth to children with intellectual disability, developmental delay, multiple malformations, or similar syndromes with unknown causes; prenatal diagnosis of abnormal fetuses detected by ultrasound; and genetic screening of newborns with birth defects.
Clinical applications in pediatric genetic diseases: chromosomal microdeletion and microduplication are important causes of congenital malformations and intellectual disabilities in children.
Clinical applications in the field of tumors: with the development of precision medicine, chromosomal microarray analysis is increasingly used in the study of the genetic background of tumors.
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