The initial standards of puberty were published in approximately 1970 by Marshall and Tanner. It is during the initial increment in growth velocity that the first sexual sign of puberty occurs. The first somatic change associated with the initiation of puberty in girls is an increase in growth velocity. The focus of this chapter will be on our expanded knowledge of both the genotypes and phenotypes of the disorders presenting as abnormal puberty. In addition, new insight about the physiology of puberty and the genetics of these disorders has accumulated. The impact of these advances has had a tremendous effect on the care of patients with abnormal puberty by: changing the initial counseling provided to our patients allowing for new treatments during the time of altered pubertal growth and, providing reproductive options to individuals previously known to be infertile and some considered sterile. In recent years numerous advances have been made in molecular medicine and the assisted reproductive technologies. Abnormal puberty, whether premature or delayed, may adversely influence each of these events resulting in an untimely or altered ability for spontaneous secondary sexual development and spontaneous reproduction or abnormal growth. Intrinsic to this reproductive maturation is yet another important process of puberty: (3) a secondary wave of skeletal growth and the attainment of adult stature. The end result is the maturation of a multitude of endocrine axes necessary for (1) secondary sexual development and, (2) the attainment of the immediate capacity for reproduction. The genetic blueprint housed within the genome of the individual has long before set in motion a number of critical processes. The pubertal process is the period of transitional growth bridging the childhood years and adulthood.
For complete coverage of this and related areas in Endocrinology, visit the free online web-textbook, Introduction Molecular research and newer techniques of genetic analysis such as genome wide association studies and next generation sequencing have allowed the identification of genetic mutations that may be responsible for some of the complex diseases that cause both delayed and precocious puberty. Among phenotypic women with all or part of a Y chromosome, gonadal extirpation is recommended, the timing of which varies with their genetic analysis which is the greatest predictor of risk for germ cell tumors.
Advances in reproductive technologies have allowed women with Turner’s syndrome and MRKH to build their families. The most common diagnosis in girls with delayed puberty is gonadal failure.
Unlike precocious puberty, the definition of delayed puberty has not changed in recent years, and large studies suggest that the most common diagnosis after evaluation is constitutional delay, however, this is more common in boys presenting with delayed puberty than girls.
The optimal method of delivery and age of cessation is not known, but increases in adult height and no obvious reproductive sequelae have been demonstrated. GNRH agonists have become a mainstay of therapy in girls with precocious puberty. The early detection of significant intracranial pathology underscores the importance of the workup in young girls with true precocious puberty, and the close follow up of girls in whom a brain MRI is not initially indicated. The age for evaluation of precocious puberty has changed in the recent past due to greater understanding of the timing of pubertal development and important racial differences. Significant pathology can result in both advanced and delayed puberty and can result in altered attainment of adult height, secondary sexual characteristics and reproductive capacity. Over half of pubertal timing is considered heritable.
Puberty is the period of growth that bridges childhood to adulthood and results in physical and sexual maturity as well as the capacity for reproduction.