Human spermatozoa with large heads and multiple flagella: a quantitative ultrastructural study of 6 cases

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Abstract
Macrocephalic spermatozoa of 6 men were studied. In all cases, sperm concentration, proportion of live spermatozoa and sperm motility were very low. A range of ultrastructural abnormalities was found, essentially comprising a 3-fold increase in nuclear volume and acrosomal hyperdevelopment and malformation. There were on average 3.6 flagella for each sperm head found in the semen, some tails were separate from heads. The various defects appeared with great constancy in all of the 6 cases: this homogeneity indicated the existence of a defined semen profile whose most significant expression was sterility. In 4 of the cases large incidences of different flagellar abnormalities were also noted; whether these flagellar abnormalities are intrinsic to the above profile is not clear. Although the increase in nuclear volume suggests a disturbance in meiosis, its association with defective nuclear elongation would also indicate the existence of 1 or more anomalies of spermiogenesis. Other abnormalities already reported in other species are considered, either spontaneously in cases of mutations, or by experimental inhibition of microtubular structures.