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– You have a female patient come in with apparent breast development but no dark pubic hair – and she’s 7 years old. Is it a case of early puberty, a warning sign to test for possible conditions, or an unremarkable departure from typical development that does not require any intervention?

The answer to situations such as these varies, explained Dennis Styne, MD, professor of pediatrics, and Yocha Dehe Endowed Chair in Pediatric Endocrinology, at the University of California, Davis.

“We don’t know why puberty begins when it does even though we know many of the controlling factors,” Dr. Styne said at the annual meeting of the American Academy of Pediatrics, but it’s important to understand when “early” is so early that you should order lab evaluations, as opposed to simply letting an outlier’s body development continue as it would.

Normal puberty

Dr. Styne reviewed the Tanner stages of puberty for girls’ breast and pubic hair development and boys’ genital and pubic hair development, noting that the classic lower ages of pubertal onset are age 8 years in girls and 9 years in boys. Yet the normal curve may actually start earlier than those ages for U.S. girls, he noted. He shared the results of a 1997 Pediatrics study of 17,077 girls, in which by age 7 years, more than a quarter of black girls (27%) and 7% of white girls had reached at least Tanner stage 2. At age 8, nearly half of black girls (48%) and 15% of white girls had reached at least stage 2 (Pediatrics. 1997 Apr;99[4]:505-12).

 

Further, breast development, menarche, and early pubic hair development (pubarche) all occur earlier with increased body mass index, which has been increasing among children overall. Another study identified earlier breast development without increased body mass index: Stage 2 development occurred an average 10 months earlier in girls in 2006 than in 1991, regardless of BMI, even though no difference in LH or FSH levels occurred at these ages and estradiol level was even lower. The authors of that Danish study concluded some other factors besides pubertal hormones had to account for the increasingly earlier breast development in girls. Endocrine-disrupting chemicals are a possible cause.

Similarly, puberty in boys is occurring a bit earlier, but less dramatically so: A 2012 study of 4,131 boys found that 5.75% of black boys, 0.54% of white boys, and 1.16% of Hispanic boys had stage 2 pubic hair development by age 6. Meanwhile, 10.9% of black boys, 2% of white boys, and 2.5% of Hispanic boys began puberty with stage 2 pubic hair development at age 8 (Pediatrics 2012;130:e1058-68).

But the boys differ in one key way from the girls: Boys with obesity tend to begin puberty later than those with normal or overweight BMIs, even though overweight boys begin puberty earlier than those with normal weights.

This leaves age 8 years as a normal age to begin puberty in boys but leaves the ages for girls’ start less certain – perhaps 7 years for white girls and 6 years for black girls – but still controversial.

When to be concerned

Various neurotransmitters in the central nervous system control puberty by suppression during childhood, until a trigger for onset occurs that remains mysterious. But gene mutations, such as MKRN3 in girls, as well as brain tumors or trauma, can remove that disinhibition, prompting further investigation. Brain tumors causing precocious puberty are more common in boys than girls.

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– You have a female patient come in with apparent breast development but no dark pubic hair – and she’s 7 years old. Is it a case of early puberty, a warning sign to test for possible conditions, or an unremarkable departure from typical development that does not require any intervention?

The answer to situations such as these varies, explained Dennis Styne, MD, professor of pediatrics, and Yocha Dehe Endowed Chair in Pediatric Endocrinology, at the University of California, Davis.

“We don’t know why puberty begins when it does even though we know many of the controlling factors,” Dr. Styne said at the annual meeting of the American Academy of Pediatrics, but it’s important to understand when “early” is so early that you should order lab evaluations, as opposed to simply letting an outlier’s body development continue as it would.

Normal puberty

Dr. Styne reviewed the Tanner stages of puberty for girls’ breast and pubic hair development and boys’ genital and pubic hair development, noting that the classic lower ages of pubertal onset are age 8 years in girls and 9 years in boys. Yet the normal curve may actually start earlier than those ages for U.S. girls, he noted. He shared the results of a 1997 Pediatrics study of 17,077 girls, in which by age 7 years, more than a quarter of black girls (27%) and 7% of white girls had reached at least Tanner stage 2. At age 8, nearly half of black girls (48%) and 15% of white girls had reached at least stage 2 (Pediatrics. 1997 Apr;99[4]:505-12).

 

Further, breast development, menarche, and early pubic hair development (pubarche) all occur earlier with increased body mass index, which has been increasing among children overall. Another study identified earlier breast development without increased body mass index: Stage 2 development occurred an average 10 months earlier in girls in 2006 than in 1991, regardless of BMI, even though no difference in LH or FSH levels occurred at these ages and estradiol level was even lower. The authors of that Danish study concluded some other factors besides pubertal hormones had to account for the increasingly earlier breast development in girls. Endocrine-disrupting chemicals are a possible cause.

Similarly, puberty in boys is occurring a bit earlier, but less dramatically so: A 2012 study of 4,131 boys found that 5.75% of black boys, 0.54% of white boys, and 1.16% of Hispanic boys had stage 2 pubic hair development by age 6. Meanwhile, 10.9% of black boys, 2% of white boys, and 2.5% of Hispanic boys began puberty with stage 2 pubic hair development at age 8 (Pediatrics 2012;130:e1058-68).

But the boys differ in one key way from the girls: Boys with obesity tend to begin puberty later than those with normal or overweight BMIs, even though overweight boys begin puberty earlier than those with normal weights.

This leaves age 8 years as a normal age to begin puberty in boys but leaves the ages for girls’ start less certain – perhaps 7 years for white girls and 6 years for black girls – but still controversial.

When to be concerned

Various neurotransmitters in the central nervous system control puberty by suppression during childhood, until a trigger for onset occurs that remains mysterious. But gene mutations, such as MKRN3 in girls, as well as brain tumors or trauma, can remove that disinhibition, prompting further investigation. Brain tumors causing precocious puberty are more common in boys than girls.

 

– You have a female patient come in with apparent breast development but no dark pubic hair – and she’s 7 years old. Is it a case of early puberty, a warning sign to test for possible conditions, or an unremarkable departure from typical development that does not require any intervention?

The answer to situations such as these varies, explained Dennis Styne, MD, professor of pediatrics, and Yocha Dehe Endowed Chair in Pediatric Endocrinology, at the University of California, Davis.

“We don’t know why puberty begins when it does even though we know many of the controlling factors,” Dr. Styne said at the annual meeting of the American Academy of Pediatrics, but it’s important to understand when “early” is so early that you should order lab evaluations, as opposed to simply letting an outlier’s body development continue as it would.

Normal puberty

Dr. Styne reviewed the Tanner stages of puberty for girls’ breast and pubic hair development and boys’ genital and pubic hair development, noting that the classic lower ages of pubertal onset are age 8 years in girls and 9 years in boys. Yet the normal curve may actually start earlier than those ages for U.S. girls, he noted. He shared the results of a 1997 Pediatrics study of 17,077 girls, in which by age 7 years, more than a quarter of black girls (27%) and 7% of white girls had reached at least Tanner stage 2. At age 8, nearly half of black girls (48%) and 15% of white girls had reached at least stage 2 (Pediatrics. 1997 Apr;99[4]:505-12).

 

Further, breast development, menarche, and early pubic hair development (pubarche) all occur earlier with increased body mass index, which has been increasing among children overall. Another study identified earlier breast development without increased body mass index: Stage 2 development occurred an average 10 months earlier in girls in 2006 than in 1991, regardless of BMI, even though no difference in LH or FSH levels occurred at these ages and estradiol level was even lower. The authors of that Danish study concluded some other factors besides pubertal hormones had to account for the increasingly earlier breast development in girls. Endocrine-disrupting chemicals are a possible cause.

Similarly, puberty in boys is occurring a bit earlier, but less dramatically so: A 2012 study of 4,131 boys found that 5.75% of black boys, 0.54% of white boys, and 1.16% of Hispanic boys had stage 2 pubic hair development by age 6. Meanwhile, 10.9% of black boys, 2% of white boys, and 2.5% of Hispanic boys began puberty with stage 2 pubic hair development at age 8 (Pediatrics 2012;130:e1058-68).

But the boys differ in one key way from the girls: Boys with obesity tend to begin puberty later than those with normal or overweight BMIs, even though overweight boys begin puberty earlier than those with normal weights.

This leaves age 8 years as a normal age to begin puberty in boys but leaves the ages for girls’ start less certain – perhaps 7 years for white girls and 6 years for black girls – but still controversial.

When to be concerned

Various neurotransmitters in the central nervous system control puberty by suppression during childhood, until a trigger for onset occurs that remains mysterious. But gene mutations, such as MKRN3 in girls, as well as brain tumors or trauma, can remove that disinhibition, prompting further investigation. Brain tumors causing precocious puberty are more common in boys than girls.

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