Familial Turner Syndrome

Seven women in three generations of a family have been affected by Turner syndrome. Turner phenotype in this family is the result of deletion of the entire short arm of one X chromosome. The short arm deletion is transmitted by carriers of a balanced X-l translocation. Autoradiographic findings showed that the deleted X chromosome was late labeling in those persons with Turner syndrome, whereas the normal X chromosome was late replicating in carriers of the balanced translocation. The results of Xga typing of erythrocytes suggest that the Xg locus is on the short arm of the X chromosome. Because of the clinical implications, we believe that families of persons with structural chromosomal abnormalities should be studied to exclude familial transmission. STRUCTURAL ABNORMALITIES of the X chromosome may be associated with a clinical picture that ranges from normal phenotypes to phenotypes indistinguishable from 45,X Turner syndrome. Generally, complete deletions of the short arm of an X chromosome result in women with the complete signs of Turner syndrome—short stature, gonadal dysgenesis, and associated somatic abnormalities (1). Because Turner syndrome results in sterility, it gen-erally has not been considered a familial genetic problem. We have evaluated a 20-year-old woman with Turner phenotype who had a complete deletion of the short arm of one X chromosome. Two sisters had similar Turner phenotypes associated with the identical short-arm X de-letions. We describe here the results of cytogenetic and serologic studies of this large family in which seven per-sons over three generations were affected by Turner syn-drome