Complications

Klinefelter syndrome may increase the risk of:

• Anxiety and depression
• Social, emotional and behavioral problems, such as low self-esteem, emotional immaturity and impulsiveness
• Infertility and problems with sexual function
• Weak bones (osteoporosis)
• Heart and blood vessel disease
• Breast cancer and certain other cancers
• Lung disease
• Metabolic syndrome, which includes type 2 diabetes, high blood pressure (hypertension), and high cholesterol and triglycerides (hyperlipidemia)
• Autoimmune disorders such as lupus and rheumatoid arthritis
• Tooth and oral problems that make dental cavities more likely
• Autism spectrum disorder

A number of complications caused by Klinefelter syndrome are related to low testosterone (hypogonadism). Testosterone replacement therapy reduces the risk of certain health problems, especially when therapy is started at the beginning of puberty.