The following symptoms and complaints may indicate Klinefelter syndrome:
Leading symptoms
- Delayed development of secondary sexual characteristics (beard growth and secondary sexual hair are sparse) and puberty.
- Gynecomastia (enlargement of the mammary gland; up to one third of cases).
- Small, firm (hardened) testicles (volume: 2-3 ml).
- Small penis
- Primary infertility in the 47,XXY karyotype: 90% of cases have azoospermia (absence of sperm cells in semen)
- Subfertility in mosaic forms: Oligospermia (less than 15 million sperm per ml of ejaculate).
- Tall stature (increased growth of long tubular bones/”eunuchoid tall stature” due to delayed epiphyseal closure/conversion of cartilaginous to bony substance) with large hands/feet but small head.
- Minor mental developmental delay (4% of cases; Lernschwierigkeien about 75% of cases).
- In adulthood, increasing overweight, which is mainly on the trunk shows (so-called Stammadipositas).
- Decrease in libido and potency (70% of patients from the age of 25).
- Lumbago and other musculoskeletal complaints as a result of developing osteopenia (reduction in bone density) and osteoporosis (bone loss).
Attention. Based on medical registries in Denmark, it is believed that only 25% of all patients with Klinefelter syndrome are diagnosed.
