Kallmann syndrome is a condition characterized by delayed or absent puberty and an impaired sense of smell. This is a condition resulting from a lack of production of certain hormones that direct sexual development (conditions known as hypogonadotropic hypogonadism). These hormones are normally made in a part of the brain called the hypothalamus. Kallmann syndrome occurs more often in males than in females, with an estimated prevalence of 1 in 30,000 males and 1 in 120,000 females.
