Kallmann Syndrome (KS)

What is Kallmann syndrome (KS)?

Kallmann syndrome (KS) is a rare genetic disorder characterized by a lack or delay in puberty development as well as an impaired or absence in sense of smell.  KS differs from other disorders know as congenital hypogonadotropic hypogonadism (cHH) because of the presence of lack or impairment in the ability to smell.  KS is more common in males than females.  It is estimated that KS affects 1 in 10,000 male births versus 1 in 70,000 female births.

What are the symptoms of KS?

The main symptoms of KS are related the impairment of puberty and reproductive development as well as the inability of impaired sense of smell. The symptoms vary in severity and include:

• Small penis (micropenis)
• Undescended testicles
• Lack of secondary sex characteristics such as lack of facial and genital hair development, deepening in voice in males, and the lack of breast development and menstruation in females
• Failure of one of the two kidneys to develop
• Clef lip
• Hearing loss
• Abnormal tooth development
• Infertility

What causes KS?

KS is caused by an inherited recessive trait on the X chromosome.  Males have an XY chromosome and females have an XX chromosome.  In males, the trait must be present on the X chromosome, and in females, the trait must present on both X chromosomes, causing this syndrome to be more prominent in males then females.  The inherited genetic defect causes a problem in development within the brain before birth. The areas of the brain affected by this are those responsible for development of the ability to smell and the hormones necessary for sexual development.

Are there available treatment options for KS?

Treatment options for KS include:

• Hormone replacement therapy such as estrogen for females and testosterone in males
• Fertility treatments such as in vitro fertilization as well as fertility drugs for both males and females
• Emotional support and therapy for the affects this syndrome has on the individuals’ quality of life

Where can I find more information on Kallmann syndrome (KS)?

• NORD
• NIH
• HX Benefit