Japanese familiar patients with male-limited precocious puberty

Familial male-limited precocious puberty (FMPP) is a rare disease caused by constitutively activating mutations in the luteinizing hormone receptor (L H-R) gene. In the present study, we analyzed the LH-R gene in members of a Japanese FMPP family. Two males of the family were affected and had a heter ozygous M398T mutation; one patient developed pubertal signs as early as 2 years of age, and the other at 6 years of age. Both patients had elevated s erum testosterone levels and prepubertal gonadotropin secretions. The fathe r of the latter patient carried the M398T mutation, but lacked history of p recocious puberty. Thus, phenotypic differences were observed in the three males with the same LH-R mutation belonging to the same family. In summary, we have described a Japanese family with FMPP.