Compare and Contrast - Precocious and Delayed puberty

Precocious puberty

Etiology Category	Boys	Girls
Idiopathic Central Precocious Puberty (CPP)	Idiopathic CPP is much less common in boys than in girls.	This is the most common etiology in females, accounting for 90% to 95% of all central precocity cases.
Central Nervous System (CNS) Tumors (CPP)	Structural CNS abnormalities are a highly frequent cause of CPP in males, making up 25% to 75% of cases. Tumors include hypothalamic hamartomas, optic gliomas, astrocytomas, pinealomas, ependymomas, and craniopharyngiomas.	CNS tumors can activate the HPG axis, with hypothalamic hamartomas being the most frequent organic cause. Other neoplastic lesions include optic gliomas, hypothalamic astrocytomas, and pineal tumors.
Other CNS/Congenital Lesions (CPP)	Causes include acquired insults like severe head trauma, postencephalitic scars, tuberculous meningitis, brain abscesses, and CNS radiation. Congenital malformations like hydrocephalus, arachnoid cysts, and suprasellar cysts can also initiate CPP.	Causes include inflammatory or destructive events like postencephalitic scars, tuberculous meningitis, brain abscesses, static encephalopathy, severe head trauma, neurosurgery, and cranial irradiation. Congenital causes include hydrocephalus, suprasellar arachnoid cysts, and septo-optic dysplasia.
Genetic/Monogenic Causes (CPP)	Pathogenic variants in MKRN3, DLK1, KISS1, and KISS1R/GPR54 are associated with CPP.	Monogenic defects are recognized, including mutations in the KISS1, KISS1R/GPR54, MKRN3, and DLK1 genes.
Gonadal Pathology (Peripheral Precocious Puberty - PPP)	Leydig cell tumors of the testis secrete large amounts of testosterone. Tumors secreting hCG (germinomas, chorioepitheliomas, teratomas, hepatoblastomas) can cross-react with LH receptors to stimulate testosterone production.	Autonomous estrogen-secreting ovarian follicular cysts are the most common cause of PPP in girls. Ovarian neoplasms like juvenile granulosa cell tumors, thecomas, luteomas, dysgerminomas, and gonadoblastomas are also causes.
Adrenal Pathology (PPP)	Virilizing forms of Congenital Adrenal Hyperplasia (CAH), most commonly 21-hydroxylase and 11-beta-hydroxylase deficiency, lead to excess adrenal androgens. Virilizing adrenal adenomas or carcinomas produce excessive androgens.	Feminizing adrenal tumors are rare but can cause isosexual precocity. Virilizing adrenal tumors or classic CAH produce excessive adrenal androgens, causing contrasexual precocity.
Syndromic & Genetic Causes (PPP)	Familial male-limited precocious puberty (testotoxicosis) is caused by a mutation in the LHCGR gene causing continuous Leydig cell testosterone production. McCune-Albright syndrome can cause peripheral precocity due to autonomous Leydig cell hyperplasia and testosterone secretion.	McCune-Albright syndrome causes autonomous recurrent luteinized follicular cysts. Aromatase Excess Syndrome leads to ectopic peripheral conversion of circulating androgens into estrogens.
Severe Primary Hypothyroidism (PPP)	Van Wyk-Grumbach Syndrome causes massively elevated TSH levels that interact with the FSH receptor, leading to macroorchidism without significant Leydig cell testosterone production or virilization.	Van Wyk-Grumbach Syndrome causes extremely high levels of TSH to cross-react with FSH receptors on the ovaries, driving estrogen secretion, multicystic ovaries, breast enlargement, and galactorrhea.
Exogenous Exposure (PPP)	Accidental systemic absorption of testosterone from gels, creams, or ointments used by adult male relatives can result in virilization.	Exposure to topical estrogen creams, oral contraceptives, anabolic steroids, or environmental phytoestrogens like lavender oil and tea tree oil can induce peripheral development.
Variations of Normal / Incomplete Precocity	Premature adrenarche manifests as isolated sexual hair or adult-type axillary odor driven by adrenal androgens without progressive testicular enlargement.	Variations include premature thelarche (isolated breast development), premature pubarche/adrenarche (isolated terminal sexual hair), and premature menarche (isolated prepubertal vaginal bleeding).

Delayed puberty

Etiological Category	Causes in Boys	Causes in Girls
Constitutional Delay of Growth and Puberty (CDGP)	CDGP is the most common cause of delayed puberty in males, accounting for 65% to 80% of cases evaluated in referral centers.	CDGP represents the most frequent cause of delayed puberty overall, although it is diagnosed less frequently in girls than in boys.
Functional / Transient Hypogonadotropic Hypogonadism	Causes include systemic/chronic diseases like celiac disease, inflammatory bowel disease, cystic fibrosis, sickle cell anemia, thalassemia, and chronic renal failure. Nutritional triggers include malnutrition, severe weight loss, anorexia nervosa, and excessive physical training. Endocrine causes include uncontrolled type 1 diabetes mellitus, profound hypothyroidism, Cushing syndrome, and hyperprolactinemia.	Functional suppression can be induced by chronic energy deficits, severe undernutrition, profound psychological stress, anorexia nervosa, bulimia nervosa, and athletic amenorrhea. Chronic systemic illnesses such as inflammatory bowel disease, celiac disease, cystic fibrosis, sickle cell anemia, and chronic kidney disease are also causes. Endocrine morbidities include uncontrolled type 1 diabetes mellitus, profound primary hypothyroidism, endogenous Cushing syndrome, and hyperprolactinemia.
Permanent Central Hypogonadotropic Hypogonadism	Caused by Isolated Hypogonadotropic Hypogonadism (IHH) and Kallmann Syndrome (associated with anosmia or hyposmia). Combined pituitary hormone deficiencies and acquired CNS lesions (space-occupying lesions, infiltrative diseases, trauma, radiation) are structural central causes. Associated genetic syndromes include Prader-Willi, Bardet-Biedl, Laurence-Moon, and CHARGE syndrome.	Caused by Kallmann syndrome, normosmic IHH, and Multiple Pituitary Hormone Deficiencies (MPHD). CNS lesions including craniopharyngiomas, germinomas, gliomas, acquired damage from irradiation or trauma, and infiltrative diseases can cause permanent defects. Congenital midline defects (septo-optic dysplasia) and syndromes like Prader-Willi, Laurence-Moon-Biedl, and CHARGE syndrome are also implicated.
Hypergonadotropic Hypogonadism (Primary Gonadal Failure)	Klinefelter syndrome (47,XXY) is the most common cause. Other structural/genetic causes include congenital anorchia, cryptorchidism, and Noonan syndrome. Defects in androgen biosynthesis include mutations in StAR, CYP17A1, and HSD17B3. Acquired damage can result from testicular torsion, trauma, viral orchitis, autoimmune orchitis, chemotherapy, and irradiation.	Turner syndrome (45,X and variants) is the single most common cause of hypergonadotropic hypogonadism in females. Other dysgenesis disorders include 46,XX pure gonadal dysgenesis (Perrault syndrome) and 46,XY gonadal dysgenesis (Swyer syndrome). Genetic/enzymatic defects include aromatase deficiency, 17-alpha-hydroxylase/17,20-lyase deficiency, and Savage syndrome. Acquired insults include cytotoxic chemotherapy, irradiation, autoimmune oophoritis, and galactosemia.
Structural / End-Organ Abnormalities (Eugonadism)		Patients have normal ovarian endocrine function but present with primary amenorrhea due to anatomical defects. Causes include Mayer-Rokitansky-Kuster-Hauser syndrome (Mullerian agenesis) and obstructive anomalies like an imperforate hymen or a complete transverse vaginal septum. Complete Androgen Insensitivity Syndrome (CAIS) in 46,XY genetic males also presents this way.