Gene deletions in an infertile man with sperm fibrous sheath dysplasia

BACKGROUND: Asthenozoospermia may sometimes be related to genetic structural defects of the sperm tail detectable by transmission electron microscopy. Dysplasia of the fibrous sheath (DFS) is a genetic sperm defect, characterized by dysplastic development of the axonemal and periaxonemal cytoskeleton. We report the case of an infertile man with normal sperm count and total sperm immotility in which dysplasia of the fibrous sheath, Akap3, Akap4 gene deletions, meiotic segregation of chromosomes 18, X and Y and Y microdeletions were investigated. METHODS: A 32-year-old man with a 3-year history of primary infertility presented at our Regional Referral Center for Male Infertility. Family medical history, lymphocyte karyotype, PCR analysis, physical examination, hormone assays and semen analysis were performed. RESULTS: Ultrastructural sperm evaluation showed dysplasia of the fibrous sheath. Immunostaining of AKAP4 protein was negative in sperm tails. PCR analysis revealed intragenic deletions of the Akap3 and Akap4 genes. Fluorescence in situ hybridization on sperm showed a high frequency of XY disomy. CONCLUSION: In this infertile patient, our results suggest a possible relationship between dysplasia of the fibrous sheath, partial deletions in the Akap3 and Akap4 genes and absence of AKAP4 protein in the fibrous sheath. These findings, however, were not detected in another four patients with dysplasia of the fibrous sheath. Our results require future confirmatory molecular analyses.