Partial Monosomy of 21q22.13-q22.2 in An Egyptian Boy

A rare case of de novo tnterstitialdeletion of the long arm of chromosome 21 involving 21q22.13-q22.22 is described here. This finding was detected by high resolution banding techniques and then confirmed by FISH study.The phenotypic abnormality was to some extent similar to that previously found in cases reported with deletion of 21q, spanning the long arm of chromosome 21 from the centromere to 21 q22. This is the first reported case at Kuwait Medical Genetics Centre with abrasion involving this region. It supports what was previously suggested that the critical region for full phenotype expression lies distal to 21q21, within 21q22.1-q22.2.