Purpose of review: To describe the reproductive outcomes of a heterogeneous group of male infertility conditions causing severe alterations in the sperm parameters (counts, motility, and morphology) because of chromosomal, genetic, or still unknown causes. Source of sperm, fertilization, pregnancy, live birth, and miscarriage rates of patients with Klinefelter's syndrome, Kartagener's syndrome, round-head sperm, dysplasia of the fibrous sheath (DFS), and stump-tail sperm were reviewed.
Recent findings: There are differences in the outcome according to the conditions and the source of sperm (ejaculated versus testicular). Klinefelter's syndrome patients have better reproductive outcomes when sperm is present in the ejaculate. Kartagener's syndrome shows better fertilization when testicular sperm is used; however, pregnancy rates and live births did not differ between ejaculated and testicular sperm. Samples with round-head sperm have a lower fertilization potential, pregnancy and live birth compared with Klinefelter's and Kartagener's syndromes. In men with DFS and stump-tail sperm, the reproductive outcome is poor, with low fertilization and very few babies born.
Summary: In Klinefelter's and Kartagener's syndrome, the fertilization potential and the live-birth rate are close to that obtained from nonspecific causes of sperm defects. Round-head sperm shows a lower fertility potential, but the addition of assisted oocyte activation and the use of intracytoplasmic morphologically selected sperm injection increased the rates of live birth. Conditions such as DFS and stump tail have a poor prognosis, but the number of cases described in the literature is too limited for drawing final conclusions.