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FISH for Pre-implantation Genetic Diagnosis
Published on: February 24, 2011
Detecting rearrangements in children using subtelomeric FISH and SKY
Blaise Clarkson1, Katerina Pavenski, Lucie Dupuis
1Faculty of Medicine, University of Toronto, Toronto, Canada.
American Journal of Medical Genetics
|February 13, 2002
Summary
Subtelomeric FISH and spectral karyotyping (SKY) detect cryptic chromosomal rearrangements in children with unexplained developmental delay. These advanced techniques identified clinically significant abnormalities missed by standard G-banding, improving diagnostic yield.
Area of Science:
- Genetics
- Developmental Biology
Background:
- The cause of mental retardation (MR) or developmental delay is unknown in about half of affected children.
- Standard G-banding karyotyping has limitations in detecting small or complex chromosomal abnormalities.
Observation:
- This study investigated 50 children with idiopathic MR/developmental delay and normal G-banding results.
- Two advanced FISH-based techniques, subtelomeric FISH and spectral karyotyping (SKY), were employed to identify cryptic chromosomal rearrangements.
Findings:
- Subtelomeric FISH detected three clinically significant rearrangements (4% prevalence), including a derivative chromosome 5, a recombinant chromosome 11, and a 2q deletion.
- Spectral karyotyping (SKY) identified only one of these rearrangements (2% prevalence) and did not detect any interstitial interchromosomal rearrangements.
Implications:
- G-banding karyotyping may fail to identify all clinically significant chromosomal abnormalities.
- Subtelomeric FISH and SKY are valuable tools for detecting cryptic chromosomal rearrangements in cases of unexplained developmental delay.
- These advanced techniques improve the diagnostic yield for identifying the etiology of MR and developmental delay.
