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Puberty and Final Height: Key Developmental Stages and Concerns

Explore the intricate processes of puberty and final height, focusing on gonadal maturation, secondary sexual characteristics, fertility, genetic pathways, and concerns related to delayed puberty. Delve into factors affecting height development and potential health implications.

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Puberty and Final Height: Key Developmental Stages and Concerns

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  1. PUBERTY Gonadal maturation with acquisition of secondary sexual characteristics and associated growth spurt FERTILITY AND FINAL HEIGHT

  2. Sex Determination Genetic Sex XY XX Ovary-determining genes Testis-determining genes Gonadal Sex Gonadal steroids (E2, P4) Gonadal steroids & peptides (T, DHT, MIS) Phenotypic Sex

  3. Genetic Pathway for Testis Development Bipotential Gonad Testis Development Testis Function Leydig -Testosterone ↓ Dax1 Wnt4 ↓ Sf1 Wt1 Sf1 Dmrt1 M33 Emx2 Lim1 Lhx9 Atrx Dhh Pdgf Sox9 Sox8 Sertoli -AMH -ABP -Inhibin B Insulin/IGF Gata4/Fog2 Wt1 Sf1 Sry Fgf9 Fgfr2 Sf1 Dax1 Germ cells -Spermatogenesis • Vascularization • Germ cell migration/proliferation • Inhibition of PGC meiosis • Sertoli proliferation/differentiation • Leydig cell migration/differentiation • PTM cell migration/proliferation • Testis cord formation

  4. Morphologic Steps in Testis Development XY XX Proliferation Sertoli Differentiation Migration Testis cords Vascularization Leydig cells Brennan J, Capel B: Nat Rev Genet 5: 509, 2004

  5. Hypothalamus GnRH pulses GnRH LH pulses Pituitary LH FSH Gonads Inhibin T E2 P

  6. PUBERTY Gonadal maturation with acquisition of secondary sexual characteristics and associated growth spurt FERTILITY AND FINAL HEIGHT

  7. PUBERTY Average age of onset: • 11.4 years in girls • 12.0 years in boys First signs of pubertal maturation: • breast budding in girls • increase in testicular volume in boys

  8. TANNER’S STAGING OF PUBERTY IN BOYS

  9. Testosterone produced by Leyding cells induces/ maintains secondary sexual characteristics and sustain germ cell production • Virilization of external genitalia • Phallus growth • Pubic, axillary, facial hair • Libido • Erections/ejaculate • Voice change • Body composition • Bone mineralization

  10. CONCERNS RAISED BY DELAYED PUBERTY • Possibly sinister underlying cause • Fear that puberty will never occur • Emotional and psychosocial upset of immaturity, specially when associated with short stature • Long term sequelae: ? Reduced bone mineralization

  11. DELAYED PUBERTY • Absence of a clear pattern of pulsatile gonadotrophin secretion • Pre-pubertal LH and FSH levels • Development of secondary sexual characteristics • Normal "Consonance" • Bone age delay • Final height is not impaired except if severe degree of delay

  12. Male Homosexuality: Nature or Culture? • 1500 species • Data mostly in males: more common more studied more confronted by religion • Genetic • Autoimmune • Neurohormonal Jannini 2010

  13. Nature - BIOLOGY Inherited from the mother Cause or result

  14. Brain Anatomy Swaab 2004

  15. Nature – Culture Biology • Older brother – more biological brothers ++ more immunity? • Fertility Advantage of carrying the HM gene (Camperio-Ciani 2008) • Ratio of 2D:4D (lower-male, higher-female) • Nature does not deny Nurture • Culture denies Nature!

  16. Older brothers and hand preference

  17. “Half Woman”??? Testosterone - higher (Brodie 1974, Jannini 2009) Testicular feminization example CAH Fetal Brain epigenetics Sexual activity - higher

  18. Penis - Longer (Ghanem 2007) (Bogaret 1999)

  19. Nature • recent genetic study 2005 • a full genome scan • 456 individuals from 146 families with two or more homosexual brothers 3 locuses and X chromosome 28q

  20. A genome-wide scan of male sexual orientation Journal of Human Genetics (2010) 55 Sreeram V Ramagopalan, Journal of Human Genetics (2010)

  21. Culture • low paternal presence, high maternal cures • Oedipus Diagnostic and Statistical Manual of Psychological Disorders (DSM-IV-TR) - “homosexuality” absent

  22. Culture • early childhood traumas • propose a reparative therapy • based on psychoanalysis, group therapy, and spiritual help

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