Characterization of aneuploidy rates, protamine levels, ultrastructure, and functional ability of round-headed sperm from two siblings and implications for intracytoplasmic sperm injection.

OBJECTIVE: To characterize and contrast protamine levels, chromatin decondensation, chromosome aneuploidy rates, and functional ability of round-headed sperm from two brothers with round-headed sperm syndrome.
DESIGN: Analysis of semen samples from siblings with round-headed sperm syndrome and comparison with semen of fertile donors.
SETTING: University school of medicine and laboratories. PATIENT(S): Two infertile siblings. MAIN OUTCOME MEASURE(S): Sperm aneuploidy rates of chromosomes X, Y, 13, 18, and 21, protamine 1 and 2 (P1-P2) ratios, Western blot evaluation of protamines, and chromatin decondensation rates. Additional measures include standard semen quality parameters, electron microscopy ultrastructure evaluation, analysis of acrosome morphology, and sperm penetration rates. RESULT(S): Aneuploidy rates were significantly increased in sibling no. 1 but not in sibling no. 2. The levels of P1 and P2 were decreased in sibling no. 1, and an unusual level of protamine precursors was present. Ultrastructural differences also were observed between the siblings. CONCLUSION(S): These data indicate profound differences in sperm from two siblings with complete round-headed sperm syndrome. Multigenic defects and/or variable expression of the syndrome may be responsible for the syndrome and necessitate individual screening of affected individuals because the pattern of expression appears highly variable.