Application of Fluorescence in situ Hybridization (FISH) Technique to Discern Complete/Partial Monosomy 21

The present study pertains to a 7 month old female infant who showed dysmorphic features and developmental delay. Conventional cytogenetic analysis by GTG banding technique was carried out and this revealed monosomy 21. Interphase FISH and metaphase FISH were employed for better delineation of the observed results. FISH analysis confirmed unbalanced X;21 translocation. This study concludes that FISH technique along with conventional cytogenetic analysis serves for better understanding and interpretation of complete/ partial autosomal monosomies.