Dysplasia of the fibrous sheath: an ultrastructural defect of human spermatozoa associated with sperm immotility and primary sterility.

A study of a group of five patients presenting with primary sterility and showing severe sperm immotility is presented. Most spermatozoa in these patients showed rigid, short, thick, and/or irregular tails and 95 to 100% were immotile. Electron-microscopy disclosed a common pattern of flagellar abnormalities. There was a dysplastic development of the fibrous sheath, which appeared hyperplastic and disorganized. The axoneme was either missing or grossly distorted. In a few instances, a normal flagellum could be identified. Similar alterations also were detected in maturing spermatids, suggesting that the described defect develops during spermiogenesis. Two of the five patients had recurrent bronchial and sinusal infections and bronchiectasis, suggesting the possible existence of an associated abnormality in respiratory cilia. The existence of a common ultrastructural defect affecting most spermatozoa, its presence in two brothers, and the possibility of association with immotile respiratory cilia point to the existence of a syndrome (namely the "dysplasia of the fibrous sheath") of possible familial transmission.