Can a young child be genetically tested for various learning disabilities?
The standard investigation for learning disability is to stain chromosomes to reveal their unique banding pattern and then to look for any anomalies using light microscopy. However, the resolution of this routine cytogenetic approach is limited since very small rearrangements are not visible and larger abnormalities escape notice if they occur in regions where the banding pattern is not distinctive. There have been many attempts to increase reliability and resolution, but there is still no practical way to screen the entire human genome for rearrangements, regardless of size or chromosomal location. However, an alternative to whole genome screening, which has transformed our diagnostic capabilities, is to focus on specific chromosomal regions, in particular the chromosome ends, known as telomeres. Some years ago molecular investigation of the chromosomal disorders implicated in learning disability established that cytogenetically undetectable rearrangements involving telomeres could gi
