Sir.—Dr Ruvalcaba's letter concerning the rarity of familial isosexual precocity in females intrigued us, since anecdotally our experience was different.1 We then reviewed the charts of 58 girls in whom isosexual precocious puberty had been diagnosed. They were all seen in our endocrine clinic over the past six years. Three girls (5.2%) had family histories indicating that other family members had also experienced sexual precocity.
Patient Reports.—Patient 1.—A girl aged 7 years 11 months had onset of breast development at age 6 years and pubic hair development at 7½ years of age. Her height age was 11½ years. Breast and pubic hair development were each at Tanner stage III. Her bone age was 11½ years. Laboratory values included: follicle-stimulating hormone (FSH), 3.2 mIU/mL (IU/L); luteinizing hormone (LH), 4.7 mIU/mL (IU/L) (prepubertal normal levels for each, 5 mIU/mL [IU/L]); and estradiol, 58 pg/mL (213 pmol/L) (prepubertal normal,
ROHN R, ROUSONELOS G. Familial Sexual Precocity. Am J Dis Child. 1986;140(8):741-742. doi:10.1001/archpedi.1986.02140220023017