The extent of clinical expression in cases of segmental aneuploidy often varies depending on the size of the chromosomal region involved. Here we present clinical and cytogenetic findings in a 5-month old boy with a duplication of a chromosomal segment 4p16.1-->4pter and a deletion of a chromosomal segment 8p23.1-->8pter. His karyotype was determined by applying classical GTG banding and FISH method (WHCR region, centromere 4, centromere 8, telomere 8p) as 46,XY,der(8)t(4;8)(p16.1;p23.1).ish der(8)t(4;8)(D8S504-,WHCR+,D8Z2+)dn. Parents are not related and have normal karyotypes, indicating de novo origin. We have compared similarity of the clinical features in our proband to other patients carrying only a duplication of the distal part of 4p or a deletion of distal part of 8p or similar combination described in the literature.