Luteinizing hormone (LH) has a crucial role in human sexual development. Mutations in the LH receptor (LHR) affects both males and females.
In boys, the mutations may cause reverse extremes, such as precocious puberty, in which genital growth and pubic hair begin forming between ages two to five. Or, in opposing situations, malformed genitals appear, including micropenis (small penis), hypospadias (urethra opening on the underside of the penis), or bifid scrotum (divided scrotum). Because of this, the genitalia may be ambiguous, clearly neither male nor female.
In girls, since the luteinizing hormone triggers the release of egg cells from the ovaries (ovulation), LHR mutations cause abnormalities in menstruation, lack of ovulation, and therefore infertility. Otherwise, genitalia, breasts and pubic hair development may be normal.