Question | Answer |
rationale behind learning about disorders of sexual development, provides background information for these two purposes... | 1. determining sex for child rearing, 2. possibility of associated metabolic disorders that may be life threatening |
when do you do investigation with DSD? | ambiguous genitalia, apparent female with enlarged clitoris, posterior fusion of labia, inguinal/labial mass. apparent male with nonpalpable testes, hypospadias, family history of DSD |
problems in these regions of the X chromosome can lead to disorders of sexual development | pseudoautosomal region 1, androgen receptor |
problems in these regions of the Y chromosome can lead to DSD | pseudoautosomal region 1, SRY |
46, XY DSD classification indicates what | male pseudohermaphrodite, undervirilization of an XY male, undermasculinization of an XY male. |
what are four causes of 46, XY DSD | gonadal dysgenesis, diefect in biosynthesis of testosterone, 5alpha reductase deficiency, adrogen insensitivity |
what is the most common cause of 46, XY DSD | androgen insensitivity |
define gonadal dysgenesis | impairment of primordia of the fetal testes, mutations in genes driving formation of the gonad. There is not normal development of the testicular tissue. |
list three categories of gonadal dysgenesis | complete, partial, mixed |
define complete gonadal dysgenesis | total absence of functional testicular tissue |
define partial gonadal dysgenesis | partial abnormality of Leydig and Sertoli cell function during fetal development |
define mixed gonadal dysgenesis | one gonad: poorly developed testes associated with Wolfian duct structures, there is only a streak of the second gonad. ex: 45, XO/ 46,XY |
what does leydig cell aplasia or hypoplasia mean with gonadal dysgenesis? | they don't develop properly, can lead to the Leydig cells failing to respond to LH |
what does inappropriate gene expression mean in terms of gonadal dysgenesis | the genes SRY, SOX9, SF1, WT1, DHH are not properly expressed |
how can defect in biosynthesis of testosterone occur? | defect in any one of the enzymes/factors invovled in the synthesis of testosterone from cholesterol. can be complete (can also suffer from CAH) or partial (reduced activity of the enzymes) |
what are three things that can happen with defect in biosynthesis of testosterone | congenital micropenis w/o hypospadias, hypogonadotropnic hypogonadism, vanishing testes |
describe congenital micropenis without hypospadias | normal development of penis in early fetal life, but failure to elongate/grow in second and third trimesters |
describe hypogonadotropic hypogonadism | these are pituitary/hypothalamic disorders (i.e. Kallmans syndrome). The testes are unable to produce sufficient testosterone |
describe vanishing testes | gonadal dysgenesis |
describe 5 alpha reductase deficiency | inability to convert T to DHT, AR trait, defect in 5 alpha reductase type 2 |
range of enzyme activity in 5alpha reductase deficiency.. | none to reduced |
can those with 5alpha reductase deficiency have normal virilization at puberty? | yes. there can be a change in gender identity, due to increased expression of 5alpha reductase type 1 |
describe androgen insensitivity | defect in the androgen receptor, hundreds of lesions in AR listed in database |
describe complete androgen insensitivity | normal functioning testes, increase in LH at puberty drives T/E2 production, leads to feale secondary sex characteristics, formerly known as "testicular feminization syndrome" |
describe partial androgen insensitivity | wide spectrum of phenotypes, regarding masculinization. at puberty, virilization poor, gynecomastia is common. impaired sexual function in individuals raised as males |
list causes of 46, XX DSD | 1. abnormal gonadal development (ovotesticular DSD, aberrant gene expression, SRY+, SOX9 duplication), 2. abnormal fetal androgen production, 3. excess maternal androgen production, 4. deficiency in placental aromatase, 5. drugs taken during gestation |
list causes of 46, XX DSD | 1. abnormal gonadal development (ovotesticular DSD, aberrant gene expression with SRY+, SOX9 dup), 2. abnormal fetal androgen production,3. XS maternal androgen production, 4. deficiency in placental aromatase, 5. drugs taken during gestation |
what is the funciton of Star protein, | it allows cholesterol access from the outer mitochondrial membrane to the inner mitochrondrial membrane |
what are two consequences of Star deficiency | salt wasting, lipoid congenital adrenal hyperplasia |
describe what happens in lipoid congenital adrenal hyperplasia | cholesterol cannot enter mitochondrial membrane, so cholesterol lipid droplets accumulate in the cell. overtime, you have so much lipid in the cell that it disrupts the cellular function and cellular membrane. cell integrity is ruined. |
list some consequences of lipoid CAH | lack of steroid hormones leads to incr ACTh, LH, FSH, since no negative feedback is present, chol accumulates in steroid producing cells (lipid droplets), the continued increase in lipid w/i cells leads to disruption of cell, damaged cells become non-func |
this is a cofactor for all microsomal P450 enzymes (17 alpha hydroxylase, 17,20 lyase, 21hydroxylase, aromatase). what is special about it? | cytochrome P450 enzymes oxidoreductase enzymes. it was recently identified as a cause of 46, XX and 46, XY DSD (disrupted stoiroidogenesis) |
this enzyme deficiency leads to hypertension | CYP 17 |
this enzyme deficiency leads to salt wasting | 3 beta HSD |
this enzyme deficiency leads to hypertension | CYP 11B1 |
this enzyme deficiency can lead to salt loss, or no salt loss, depending on how it presents. | CYP21A2 |
this chromosomal configuration leads to normal ovarian organogenesis with excessive androgen eposure | 46, XX DSD |
what results form 46, XX DSD | abnormal fetal androgen production (congenital adrenal hyperplasia), excess maternal androgen production (rare, newborn hormone levels normal), deficiency in placental aromatase (maternal virilization may occur during gestation) |
in excess androgen exposure of 46, XX fetus, what is the presentation with exposure at greater than 12 weeks gestation | clitoral enlargement |
in androgen exposure o 46, XX fetus, what is the presentation with exposure to androgen at greater than 12 weeks gestation? | abnormal development of urogenital sinus |
in androgen exposure o 46, XX fetus, what is the result with androgen exposure << 12 weeks gestation? | abnormal development of urogenital sinus with labio-scrotal area |
in androgen exposure o 46, XX fetus, what is the result of androgen exposure <<< 12 weeks gestation | formation of penile urethra in the individual, with abnormal development of urogenital sinus |
this disorder is uncommon but should always be considered. the degree of testicular development dictates wolfifian duct development and Mullerian duct regression | Ovotesticular DSD |
what is the most prevalent ovotesticular DSD | 46, XX |
what are the different forms of ovotesticular DSD | 46 XX, 46 XY, 46 XX, 46 XY mosaicism, Y to X translocations, Y to autosome translocation, mosaicism in gonads only, inactivation of X related gene that suppresses testicular development |
list some DSD associated with congenital anomalies (can result from mutations, deletions, altered expression) | WT1, Wnt4, SF1/DAX1 |
WT1 mutation results in what | WAGR syndrome, Denys-Drash syndrome, Fraiser syndrome |
Wnt4 mutation leads to what | mental retardation |
SF1/DAX1 mutation leads to what | dysfunciton in adrenal, anterior pituitary, hypothalamus |
what are the DSD associated with congenital abnormalities | Klinefelters (47, XXY), Turners syndrome (45, X), Chimerism (46XX, 46XY) |
this describes a male pseudohermaphrodite, can be caused by undervirilization of an XY male, or undermasculization of an XY male | 46, XY DSD |
this term describes a female pseudohermaphrodite. can be caused by overvirlization of an XY female, or masculanization of an XY female. | 46 XX DSD |
this describes a true hermaphrodite | ovotesticular DSD |
this describes an XX male or XX sex reversal | 46 XX testicular DSD |
this describes an XY sex reversal | 46 XY complete gonadal dysgenesis |
what is the number one cause for DSD in 46 XX? | congenital adrenal hyperplasia |