There is a host of very uncommon to rare disorders caused by gene mutations that result in male infertility. Any couple undergoing evaluation for infertility both need a complete and systematic history and physical examination by their physicians.
Chromosome disorders may be due to numerical or structural rearrangements, and can occur “out of the blue” or be inherited. The most common chromosome disorder affecting fertility in males is Klinefelter syndrome. Affected males have an extra female (X) chromosome in all or many of their cells, resulting in sterility and, less commonly, in infertility. Affected males may have marked breast development at puberty, and a majority has learning and behavior problems in childhood. Physical examination almost invariably reveals small testes, tall stature, and a feminine build. Chromosome analysis of a blood sample reveals the diagnosis.
Men who carry a balanced chromosome rearrangement (called a translocation) may also have very low sperm counts, or their sperm may fail in fertilization. Once again, a blood sample establishes the diagnosis. Other structural rearrangements of chromosomes and other numerical disorders may also interfere with sperm formation; thus, evaluation for infertility should also include a genetics consultation. Fortunately, for most men with at least a tiny production of sperm, needle aspiration of sperm directly from the testis followed by in vitro fertilization will frequently yield success.
In the face of established infertility, the route to successful pregnancy is emotionally stressful and psychologically demanding, requiring great sensitivity and understanding between partners, who hopefully share the same determination to achieve a pregnancy.