with Tuner's Phenotype in a Japanese Girl

A 13-year-old Japanese girl with a karyotype of 45,X/46,X,dic(X) (qter~p22::p22~qter) and clinical features of short stature, webbed neck, pectus excavatum and gonadal dysgenesis is described. The dic(X) chromosome was late replicating and assumed to be formed during the first mitotic division. Review of 17 previously published cases with a dic(X) (qter~p22::p22~qter) and the present case revealed no relationship between the phenotype and the percentage of 45,X cells. Therefore, the difference in volume and the part of the chromatin lost by forming a dic(X) chromosome may be mainly responsible for the expression of the phenotype.