Mosaic double aneuploidy (45,X/47,XX,+8) with aortic dissection

Chromosomal aneuploidy is considerably frequent and may involve either autosomes or sex chromosomes. While double aneuploidy involving both autosomal and sex chromosomes is rare, several reports described the cases of sex chromosomal aneuploidies in combination with trisomy 21, such as Down-Klinefelter and Down-Turner syndrome. However, trisomy 8-Turner syndrome has been rarely described to date. Here we report a case of a 28-year-old female with mosaic trisomy 8-Turner syndrome. The patient was referred to our hospital for aortic dissection. On physical evaluation, features of her phenotype, which included short stature, webbed neck and cubitus valgus, suggested congenital anomalies such as Turner syndrome. Chest CT revealed aortic dissection with bicuspid aortic valve and coarctation. G-banding cytogenetic analysis of peripheral blood showed mosaicism with two cell lines (45,X[17]/47,XX,+8[33]). FISH analysis indicated that 15% of the cells were of monosomy X karyotype and 85% of the cells were with XX karyotype and trisomy 8 was detected only in XX cells. Though the patient exhibited clinical features of Turner syndrome, somatic stigmas present were not clearly distinguishable from those of trisomy 8, such as short stature, skeletal and cardiac abnormalities. Observations from most of the double aneuploidy cases indicated that the patient's phenotype was not necessarily in correlation to the ratio of autosomal and sex chromosomal aberrations. Mosaicism in trisomy 8-Turner syndrome was rarely documented and we believe this is the first reported case of mosaicism in trisomy 8-Turner syndrome presenting with aortic dissection and surviving into adulthood.