What is the DNA microarray analysis used for?

DNA - array diagnostics

Many patients with retardation syndromes (developmental retardation) or isolated developmental retardation / intellectual disability can often not be assigned to any known syndrome. A specific examination is therefore not possible. In these patients, often children, there may be microdeletions and duplications that can only be detected in a genome-wide DNA microarray examination because they are below the detection limit of conventional chromosome diagnostics (approx. 5 megabase pairs / Mb = 5 million base pairs). The symptoms are caused by the very different losses or gains of chromosomal material in individual patients and are often not described as a specific syndrome.

With detailed information about which genes are affected by a deletion or a duplication, a specific genotype-phenotype correlation can be achieved.

Genome-wide DNA microarray diagnostics may be performed as a health insurance service. Through genome-wide DNA array analyzes, explanatory diagnoses can be made in approx. 10-15% of patients with unexplained developmental delay. At the Institute for Human Genetics, an array (SurePrint G3 Human CGH, 4x180K) is used, which achieves an average technical resolution of approx. 48.2 kb.

More often, rare variants have to be further clarified through parental examinations (segregation analysis). For this, after an initial evaluation, parent EDTA blood samples are requested.

Duration of the investigation

  • Index patient without further clarifications such as qPCR: usually 8 weeks after receipt / order placement
  • Index patient for whose further clarification parent material is available: usually 12 weeks after receipt
  • If parent material is only requested from the index patient after an imbalance has been detected: usually 8 weeks after receipt of the parent material