Kallmann syndrome is a type of hypogonadotropic hypogonadism, associated with hyposmia or anosmia (reduced or absent sense of smell). A normal to low serum concentration of LH and FSH in the presence of low concentrations of the sex steroids and absence of any other hypothalamic or pituitary abnormalities is indicative of Kallmann syndrome.
The genetic defect involved in KAL1 is of the Kallmann Syndrome Interval Gene 1 (KALG1 or KAL1) gene on the X chromosome.