Physical retardation is associated with ring chromosome mosaicism: 46, XX,r(10)/45, XX,10 minus

Cytogenetic analysis of peripheral leucocytes of a 9-year-old girl presenting with retardation of physical development indicated mosaicism for a ring 10 chromosome. Serum aspartate transaminase was within normal limits. A survey of eight markers failed to show syntenic relations with chromosome 10.