Hypogonadism Caused by a Single Amino Acid Substitution in the β Subunit of Luteinizing Hormone

INFERTILITY occurs in approximately 10 to 20 percent of couples and can be attributed to a reproductive disorder in the man or woman with equal frequency.1 , 2 Among men, specific causes of infertility can be identified in only a minority.1 In a previously identified kindred in which several men were infertile, the proband had not undergone spontaneous puberty and had low testosterone and elevated luteinizing hormone concentrations in serum, a pattern of hormone values indicative of primary hypogonadism.3 However, testosterone secretion in response to the administration of exogenous luteinizing hormone and human chorionic gonadotropin was normal. Thus, the proband appeared to . . .