DNA microarrays

Applied technology

We offer different types of microarrays with the high resolution genomic platform by Agilent. The DNA microarrays can detect different types of alterations in DNA:

– Detecting SNP:

Single-nucleotide polymorphisms (SNP). This type of mutation affects the product of the affected gene expression (generally a protein) differently. This protein can stop being functional, modify its activity or even be a silent mutation and not affect anything.

Array CGH:

The array CGH (molecular karyotyping) is a technique used in genetic diagnosis that allows us to analyse the complete genome of an individual that is looking for genetic gain or loss alterations in very short period of time. The array CGH (molecular karyotyping) used at Bioarray is guaranteed by the company Agilent technologies, world leader in the development of oligonucleotide platforms. These arrays CGH (molecular karyotyping) allow the detection of deletions or duplications in the genomic material with a 200kb resolution.
 

Why use this new technology?

Bioarray offers array CGH (molecular karyotyping) of oligonucleotides that cover the complete genome with different resolutions. The array CGH (molecular karyotyping) designs by Agilent technologies are especially aimed at detecting alterations with clinical consequences. From a cost/beneficial point of view, it is necessary to take into account that this technology is equivalent to hundreds of combined FISH assays throughout the whole genome. For this reason, the array CGH (molecular karyotyping) should be considered as the first alternative in the study of gains and losses of genomic material.

Bioarray offers array CGH (molecular karyotyping) of oligonucleotides that cover the complete genome with different resolutions.
The array CGH (molecular karyotyping) designs by Agilent technologies are especially aimed at detecting alterations with clinical consequences. From a cost/beneficial point of view, it is necessary to take into account that this technology is equivalent to hundreds of combined FISH assays throughout the whole genome. For this reason, the array CGH (molecular karyotyping) should be considered as the first alternative in the study of gains and losses of genomic material.

 

 What is the function of array CGH?

The array CGH (molecular karyotyping) enables the comparison of the number of DNA copies between a testing sample and a healthy control.
Both DNAs are marked with different colours and are hybridised together in the array. The analysis is carried out in a quantitative manner, by calculating the proportion of DNA of each colour for each genomic region of the case study with regard to the healthy control.
The detected gains and losses are analysed to discard the presence of these variations in a healthy population. In addition, different data bases are checked to determine the relation between the patient’s clinical profile and the observed alterations.

In some cases, the presence of alterations, that were not previously described, make it necessary for a study of the parents to be carried out. In this sense, the possibility of an inherited alteration, that is not responsible for the patient’s clinical profile, is discarded. Finally, before requesting this test, it is important to take into consideration the limitations of this technology. With the array CGH (molecular karyotyping), some alterations, that do not imply a loss or gain of genomic material, will be able to be diagnosed, such as point mutations, translocations or balanced inversions.
 

When is it advised to use array CGH?

The array CGH (molecular karyotyping) is recommended for patients with a normal karyotype and with a clinical profile with:
  • Unexplained intellectual disability or development delay.
  • Congenital anomalies or dysmorphic features.
  • Autistic disorders or clinical presentations that suggest a specific chromosomal syndrome.
In addition, it is indicated for altered karyotypes:
  • In patients with apparent balanced translocations with an abnormal clinical phenotype
  • In the presence of duplications or deletions in the karyotype to determine the limits of the altered region.
  • When marker chromosomes are identified to determine its origin.

 – Expression: it measures the levels of expression in the genes of interest. This technique is essential in the study of diseases related to the levels of abnormal expressions, such as many types of cancer in which a number of overexpressed genes have been described.

– ChIP-on-Chip: this type of array is used to monitor DNA-binding proteins in the areas around the promoters.

– Methylation: this allows us to monitor the methylation in the CpG islands, surrounding areas of the promoters and defined regions.

– miARN: these are microarrays that allow us to obtain an expression profile of this type of ARN.