The aCGH test, unlike the classic karyotype test, is used not only to detect aneuploidies in all human chromosomes, but also to identify very minor changes within them (so-called submicroscopic chromosomal aberrations). This can be a microduplication, i.e. a doubling of some small fragment of DNA, or a microdeletion, i.e. a loss of DNA.

Karyotype analysis

Due to limited resolution, classical cytogenetics is not always able to detect small chromosomal rearrangements. With the help of cytogenetic microarrays, whose resolution is higher, small changes in the number of chromosomes, such as microdeletions or microreplications, can be identified. Detection of such changes makes it possible to make a proper diagnosis.

Examination of abortion material

Examination of abortion material using cytogenetic microarrays provides the opportunity to determine the causes of intrauterine fetal death or stillbirth. This method allows to analyze genetic material also from paraffin block, which is difficult to handle. Thanks to the high resolution of the microarray, we can detect small chromosome aberrations responsible for fetal death.

Prenataltesting

An abnormal ultrasound result during pregnancy is an indication for more accurate prenatal testing, such as amniocentesis or chorionic villus biopsy. Thanks to the high resolution of microarrays, small changes in the fetal karyotype become detectable. The result of the test can confirm or exclude the presence of genetic defects, associated with microduplication/microdeletion syndromes, which makes it possible to decide how to manage the pregnancy. Cytogenetic microarrays also allow the detection of contamination of collected fetal cells, with material from the mother, which is a relatively common occurrence. Genetic testing performed with this technique minimizes the risk of misdiagnosis and its possible consequences.

Diagnosing genetic disorders in children

Diagnosing some genetic diseases can be difficult due to an ambiguous clinical picture or the results of other diagnostic tests. Microarray analysis can identify chromosomal abnormalities responsible for developmental disorders, including intellectual disabilities, multiple birth defects, dysmorphic features, autism spectrum disorders, epilepsy and many others. A correct diagnosis makes it possible to quickly implement appropriate therapy.

The sample for microarray testing can be peripheral blood (about 1-2 ml), amniotic fluid (about 5 ml) or appropriately protected material from a spontaneous miscarriage. Microarray technology is based on fluorescently labeled molecular probes that attach to specific sites in the genetic material. The signal from the probes is recorded and analyzed by a special device, and only on the basis of this is the patient’s karyotype and the change in the number of copies of variants determined. The resulting microarray image goes first to bioinformatics analysis and then to the laboratory diagnostician, who evaluates it.

Due to its very high resolution and wide range of analysis, the aCGH test makes itpossible to detect changes in the number of individual human chromosomes.

Performing a molecular karyotype is recommended in cases such as:

• The suspected presence of a defect with a genetic basis
• The presence of dysmorphia
• The presence of autism spectrum disorders
• Presence of intellectual disability
• The birth of a child with a genetic defect
• Recurrent miscarriages
• Fetal demise
• Abnormal prenatal ultrasound results
• Difficulty in getting pregnant

• During one test, it is possible to detect changes in all chromosomes
• The test detects both large and small changes in chromosomes (microdeletions, microduplications)
• The test provides an opportunity to shorten the diagnostic process
• The test provides an opportunity to reduce the cost of diagnosis
• Thanks to the test, the patient can start effective treatment sooner
• The result of the test is valid for life and can also be used in the future