Central precocious puberty: When puberty hits early

Although research suggests that the onset of puberty is occurring earlier and earlier, experts still use traditional thresholds to diagnose puberty as abnormally early.

Central precocious puberty is the term used when boys or girls enter into the process of sexual development earlier than normal. Normal age ranges have been decreasing for generations in both boys and girls, but puberty is generally accepted to occur within a normal range between the ages of:

• 8 and 13 years in girls
• 9 and 14 years in boys

Moving the lower limit has been considered to address the trend of decreasing age at puberty onset in both boys and girls,¹ but specialists have relied on these traditional ranges in order to avoid missed diagnoses for other pathological conditions that can cause the same effect.² Some of the conditions that can cause early signs of puberty include:

1. Congenital adrenal hyperplasia
2. Adrenal gland dysfunction
3. Hormone-secreting adrenal tumors

When puberty begins before age 8 years in girls and age 9 years in boys, a diagnosis of central precocious puberty may be appropriate.

Although there are many ways that puberty onset can be assessed, Katherine Kutney, MD, a pediatric endocrinologist at Rainbow Babies and Children’s Hospital in Cleveland, Ohio, said the gold standard is the presence of breast tissue before age 8 years in girls and an increase in testicular volume before age 9 years for boys. These developments are measured with the Tanner scale, a decades-old system that takes into account a combination of physical development characteristics and the appearance of pubic hair.

Diagnosing central precocious puberty takes more than just 1type of symptom, though. Kutney noted that although breast and testicular growth are the physiologic signs used to diagnose the onset of puberty, these rely on exposure to estrogens in girls or luteinizing hormone receptor activation in boys. These changes depend on when the hypothalamic-pituitary-gonadal axis is triggered, she added.

Other things that can signal central precocious puberty include:

1. Growth rates above normal prepuberty rates of 4-6 cm per year
2. Growth rates that cross over percentiles on the normal growth curve
3. The presence of white vaginal discharge in girls
4. Other signs of adrenarche like pubic hair growth

It’s possible for children in these age ranges to experience premature thelarche (breast development) or early testicular growth and premature adrenarche separately, but they occur together when central precocious puberty is diagnosed.

Often a result of a mutation in the MKRN3 gene, true central precocious puberty is considered to be rare. The condition affects roughly 1 in 5000 to 10,000 girls and even fewer boys.³

Kutney recommended that all children who are suspected to have central precocious puberty be referred to a pediatric endocrinologist for further examination. One tests that can help rule out other conditions and confirm the diagnosis is a first morning blood sample to look for elevations in gonadotropin and sex steroid—estradiol or testosterone)levels. These tests require the use of a highly sensitive assay (Liquid Chromatography/Mass Spec) to get an accurate diagnosis of these hormone elevations.

Thyroid levels should also be checked, Kutney said, as there are rare situations where severe hypothyroidism can appear as precocious puberty, like with van Wyk Grumbach syndrome. This is a rare condition where juvenile hypothyroidism, delayed bone age, and precocious puberty are combined. Treatment with thyroid hormone replacement therapy usually leads to a return to the prepuberty state when this condition is the true cause of early puberty.⁴

Endocrinology specialists will also conduct additional testing if hormone levels come back normal despite all signs pointing to central precocious puberty, Kutney added. Gonadotropin- release hormone (GnRH) or Leuprolide stimulation tests can be helpful to make a more definitive diagnosis in these situations, she stated.

Making an accurate diagnosis in cases of suspected central precocious puberty is important to rule out other pathological causes of puberty symptoms, but also to treat early onset puberty and avoid long-term complications. Complications of central precocious puberty can include⁵:

• Failure to reach full adult height
• Social problems from developing before peers
• Emotional problems
• Early sex drive and a lack of impulse control

Treatment for central precocious puberty depends on when and why it develops. Children who are near the normal age range for puberty may not be treated at all. When central precocious puberty develops significantly earlier than the typical age range, medications like GnRH agonists may be used to lower sex hormone levels and stop puberty. If the child’s early puberty is caused by another issue or underlying condition, those should be treated, as well.⁵

References

1. Eckert-Lind C, Busch A, Petersen J, et al. worldwide secular trends in age at pubertal onset assessed by breast development among girls. JAMA Pediatr. 2020;174(4):e195881. doi:10.1001/jamapediatrics.2019.5881

2. Kaplowitz P, Bloch C. Evaluation and referral of children with signs of early puberty. Pediatrics. 2015;137(1):e20153732. doi:10.1542/peds.2015-3732

3. MedlinePlus. Central precocious puberty. Updated August 18, 2020. Accessed October 28, 2021. https://medlineplus.gov/genetics/condition/central-precocious-puberty/#inheritance

4. Bhadada S, Rastogi A, Bhansali A. An unusual presentation of a usual disorder: Van Wyk-Grumbach syndrome. Indian J Endocrinol Metab. 2011;15(6):141. doi:10.4103/2230-8210.83356

5. American Academy of Family Physicians. Central precocious puberty. Updated January 2, 2020. Accessed October 28, 2021. https://familydoctor.org/condition/central-precocious-puberty/