Molecular cytogenetics

Array-based molecular karyotyping (comparative genomic hybridization, aCGH) enables identification of unbalanced chromosomal rearrangements of different sizes – microdeletions and microduplication.

The molecular karyotyping developed in the late nineties and became the first tier test for detecting chromosomal imbalances in different situations in clinical practice. It has been shown that in the group of individuals with developmental delay/intellectual disability or multiple congenital anomalies or autism spectrum disorders, molecular karyotyping detects causative pathogenic genomic rearrangement in 15-20% of cases.

In the Laboratory for Molecular Cytogenetics, molecular karyotyping was introduced into regular routine practice in 2011, first into the postnatal diagnostics, and then in 2014 into the prenatal diagnostics. In addition, we use it in specific situations as a confirmatory/explanatory method after classical cytogenetic diagnostics. Oligo-based microarrays of different resolution capacities are used (Agilent).

Indications for use in postnatal diagnostics:

– developmental delay
– intellectual disability
– congenital anomalies
– dysmorphic signs
– epilepsy
– autism spectrum disorders

Indications for use in prenatal diagnostics:
– fetal structural anomalies detected with ultrasound
– in utero growth restriction
– increased nuchal translucency (> 3,5mm)
– greatly increased risk for aneuploidies after screening tests (risk of 1:30 or higher)
– classical kariotyping identified a marker chromosome or de novo translocation
– positive noninvasive prenatal test for microdeletions

– prenatal samples/urgent tests – 17 days
– postnatal samples – 4-8 weeks

Forms

  • Instructions for sample handling (storage, sending)

  • Request form for genetic analysis

  • Informed consent for sample colleciton, genetic analysis and DNA storage

  • Request form for molecular karyotyping – clinical information