Clinical_Rounds_in_Endocrinology_Volume_II_-_Pediatric_Endocrinology

179

astrocytoma), mucocutaneous pigmentation and nevi (Peutz–Jegher syndrome),

waxing/waning of breast size (follicular cyst of ovary), hepatomegaly (hepato-

blastoma), and hyperpigmentation (CAH and glucocorticoid resistance syn-

drome) (Fig. 6.2).

16. What are the familial causes of precocious puberty?

The familial causes of GDPP are neurofibromatosis type 1, tuberous sclerosis,

gain-of-function mutation of kisspeptin gene and kisspeptin receptor (GPR54),

and rarely, constitutional precocious puberty. The familial causes of GIPP are

familial testotoxicosis, Peutz–Jegher syndrome, and congenital adrenal hyper-

plasia (21α-hydroxylase deficiency, 11β-hydroxylase deficiency, and

3 β-hydroxysteroid dehydrogenase type 2 deficiency). Precocious puberty asso-

ciated with McCune–Albright syndrome is not considered familial, as it is a

result of postzygotic gain-of-function mutation of GNAS1 gene.

17. What is the importance of gender in precocious puberty?

Precocious puberty is more common in girls than in boys (3–5:1). Gonadotropin-

dependent precocious puberty (GDPP) accounts for 70–80 % of patients with

precocious puberty, while gonadotropin-independent precocious puberty

(GIPP) contributes to the rest. Both GDPP and GIPP are more common in girls

than in boys, with a ratio of 5:1 in GDPP and 2.5:1 in GIPP. Seventy percent of

girls with GDPP have idiopathic precocious puberty, while 75 % of boys with

GDPP have CNS pathology. Although organic lesion must be excluded in all

children with GDPP, it is more likely to be present in boys. The etiology of

GIPP in boys includes hCG-secreting tumors, testotoxicosis, and Leydig cell

tumors, while in females, McCune–Albright syndrome, ovarian cyst, and expo-

sure to environmental estrogen predominate. Congenital adrenal hyperplasia,

virilizing adrenal tumors, feminizing tumors, and hypothyroidism may result in

GIPP in both genders (Fig. 6.3).

ab

Fig. 6.2 (a) Café-au-lait macule in a girl with precocious puberty, (b) X-ray of pelvis showing
deformity in upper end of the right femur (Shepherd’s crook deformity) with ground-glass appear-
ance suggestive of fibrous dysplasia

6 Precocious Puberty