A Case Report of Rare Sex Chromosomal Aneuploidy: 48,XXXY/49,XXXXY

The sex chromosome aneuploidy 49,XXXXY is a rare syndrome characterized by mental retardation, severe speech impairment, multiple skeletal defects, genital abnormalities and subtle dysmorphic features. The incidence of 48,XXXY/49,XXXXY is very rare and to our knowledge only few reports of mosaicism have been reported so far but with different cell line proportions. We describe a case with 48,XXXY[16]/49,XXXXY[4] mosaicism in a four year old boy with microcephaly, short stature, expressive speech delay, and clinodactyly. Karyotyping showed mosaicism with 48XXXY[16]/49XXXXY[4] and was confirmed by FISH analysis.