Adult and Pediatric Seventh EditionCongenital Primary Hypogonadism Chromosomal Abnormalities It has been recognized for many years that normal ovarian activity depends on the presence and function of specific X chromosomal genetic loci. Therefore, abnormalities involving any Xxxxxx xxxxxx xxxxxx sex com portion of the X chromosome in females are associated with aberrant ovarian function. Varying degrees of Assfuck skinny girls dysregulation are also observed in males with an abnormal complement of X chromosomes.
The most common karyotypic abnormalities leading to primary hypogonadism are discussed in the following sections. Turner Syndrome With an incidence of 1 in to live-born females, Malaysiansexdating com syndrome is the most common cause of primary ovarian failure. First described in by Dr. Henry Turner, the syndrome consists of a missing or structurally abnormal X chromosome combined with characteristic phenotypic features.
While many of these somatic characteristics may be the consequence of intrauterine lymphedema, the Turner syndrome phenotype in general is thought to result from a haploid dosage of genes on the X chromosome that normally escape X inactivation. Lymphedema noted at birth may prompt an early diagnosis. Alternatively, girls may present in midchildhood or adolescence with progressive short stature or delayed puberty. These follow a diphasic pattern, with plasma LH and FSH levels rising during early and late Xxxxxx xxxxxx xxxxxx sex com and exhibiting a nadir during middle years, although increased for age.
It is the most common disorder of the sex chromosomes, with an estimated incidence ranging from 1 in to 1 in live-born males. Typical features include tall stature with eunuchoid body proportions, hypogonadism, a variety of learning and behavioral problems, and borderline-to-normal intelligence. While pubertal onset may occur normally, serum testosterone levels are generally at the low end of the normal range, and inhibin B levels gradually decrease in conjunction with progressive testicular failure.
However, many patients remain undiagnosed through adolescence and may present in adulthood with infertility, azoospermia, or hypogonadism. Although the most common forms of congenital adrenal hyperplasia are associated with an excess of adrenal androgen secretion, rare defects exist in which there may be a complete inability to synthesize both androgens and estrogens. A fascinating aspect of lipoid adrenal hyperplasia is that some affected 46,XX individuals experience spontaneous puberty and normal menstrual cycles, presumably owing to steroidogenic acute regulatory-independent steroidogenesis within the ovary.
Diagnosis is based on extreme elevations of adrenal steroid precursors, and treatment consists of glucocorticoid and sex-steroid replacement as indicated by the phenotypic sex. Disorders of Sex Development Abnormalities of sexual determination and differentiation result in a number of conditions typified by either overvirilization of genetic females or undervirilization of genetic males, and are usually associated with genital ambiguity see Chapter However, rare disorders exist in which a phenotypically normal appearance is present, which may result in delayed diagnosis until abnormal pubertal development prompts medical evaluation.
Discussion of these disorders will be limited to genetic males, who may appear phenotypically female, as discussed in the following sections. A variety of mutations within the androgen receptor gene may result in qualitative or quantitative abnormalities in androgen receptor function see Chapter These patients are typically tall and present in adolescence with normal breast development, primary amenorrhea, and a paucity of pubic and axillary hair. The external genitalia are those of a normal female, although the vagina ends blindly.
The testes are intraabdominal, and no female internal reproductive organs are found. As in XY gonadal dysgenesis, women with complete androgen insensitivity are at risk for gonadal neoplasms, although the incidence appears to be low in this setting. First described inpure 46,XY gonadal dysgenesis manifests as a normal female phenotype with complete absence of secondary sexual development see Fig.
Testicular regression syndrome refers to a rare condition in which the testes become nonfunctional and involute thus the term vanishing at some point during intrauterine life or the early postnatal period. Depending on the timing of testicular regression, ambiguous or normally formed male genitalia may result. The cause of testicular regression is poorly understood but is hypothesized to be the result of a vascular insult to the testes during intrauterine life. Familial cases have rarely been reported.