RESUMO
Background: The chromosomal polymorphism of short arms of acrocentric chromosomes and heterochromatin variation of Chromosomes 1, 9, 16 and Y have been reported in humans. The pericentric inversion of Chromosome 9 is commonly seen in normal humans and the frequency estimated to be 1 to 3% in general population and inherited in mendalian fashion or might occur spontaneously without any clinical significance. Aim: The aim of the study was to study the frequency of inv(9) and its clinical correlation with human genetic diseases. Materials and Methods:0 The chromosomal analysis using GTG-banding was carried out in 3,392 cases suspected with genetic diseases. Results: The pericentric inversion frequency of different chromosomes in our study was 1.24% and frequency of inv(9)(p12q13) was high (64.29%) compared to other pericentric inversions in our study. A high frequency (9.33%) of inv(9)(p12q13) was detected in children with dysmorphic features and congenital anomalies. Conclusion: As a high frequency of inv(9)(p12q13) detected in children with dysmorphic features, the inv(9) definitely have a role in the abnormal phenotype development. During inversion event there might be loss or suppression of euchromatin chromosome region and hence detailed chromosomal break point study is important to understand the clinical significance of the pericentric inversion of Chromosome 9.
RESUMO
We have carried out chromosomal analysis in a couple with repeated spontaneous abortions (RSA). The chromosomal analysis of male revealed 15ps+ and the chromosome 15 appeared as submetacentric, C- group chromosome. First time we have attempted fluorescence in situ hybridization (FISH) using NOR probe (dJ1174 A5) and FISH analysis revealed NOR duplication on chromosome 15 which was also quantitated using Q-FISH software. The identical NOR duplication also detected in chromosome preparations from products of conception. However, NOR studies in large group of patients is necessary to understand the role of NORs in RSA.