Chromosomal microarray analysis (array Comparative Genomic Hybridization assay – aCGH)

The laboratory performs genomic high-sensitivity microarray analysis, which uses comparative genomic hybridization (CGH) to detect specific genomic abnormalities (Copy Number Variations (CNVs), deletions/duplications) associated with a particular disease. The technology offers significantly higher resolution than standard cytogenetic techniques, as well as analysis of the whole genome within a single experiment, unlike other methods (such as MLPA analysis). The clinical application of this type of analysis has been proven in terms of elucidating the etiology of intellectual disability, autism, and developmental delay, the diagnosis of rare microdeletion, or microduplication syndromes (tests 130, 131), and prenatal diagnosis of chromosomal diseases (test 132).

Indications for prenatal diagnosis by chromosomal microarray analysis 

• Ultrasound finding for increased nuchal translucency NT> or = 3.5

• Another ultrasound finding for a structural abnormality of the fetus

• Calculated high risk of biochemical screening based on ultrasound fetal morphology in the first and/or second trimester (only after excluding the most common trisomies of chromosomes 13, 18, and 21 by other molecular genetic analysis)

• Intrauterine growth retardation

• A series of miscarriages

• History of the presence of chromosomal translocation in the family

• Previous pregnancy or child with identified chromosomal aberration

The laboratory has microarrays with different resolutions, which increase the sensitivity of the method (up to 99%) for the detection of copy number variations and areas with loss of heterozygosity. At this stage, the laboratory offers the following microarrays with different resolutions:

Characteristics of oligonucleotide-based-array CGH platforms:

• SurePrint G3 Unrestricted CGH 4x44K, ISCA v2: immobilized 43,095 60-mer high-quality oligonucleotide probes, with median probe spacing of 75 Кb (lower in the regions with Ref Seq genes) with higher coverage in regions containing known genes, promoter, and telomeric regions

• SurePrint G3 Unrestricted CGH 4x180K, ISCA v2 - immobilized 170,334 60-mer high-quality oligonucleotide probes, with median probe spacing of 13 Кb (lower (11 Кb) in the regions with Ref Seq genes) with higher coverage in regions containing known genes, promoter and telomeric regions.

• SurePrint G3 Unrestricted CGH 2x400K – immobilized 411,056 60-mer high-quality oligonucleotide probes, with median probe spacing of 5.3 Кb (lower (4.6 Кb) in the regions with Ref Seq genes) with higher coverage in regions containing known genes, promoter, and telomeric regions.

• SurePrint G3 Unrestricted CGH 1x1M - immobilized 963,029 60-mer high-quality oligonucleotide probes, with median probe spacing of 2.1 Кb (lower (1.8 Кb) in the regions with Ref Seq genes) with higher coverage in regions containing known genes, promoter, and telomeric regions, which gives the platform very high resolution. 

LGD offers the following diagnostic tests using chromosomal microarray analysis: