2011 Lab 8 - Genital Abnormalities

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2011 Lab 8: Introduction | Sex Determination | Early Embryo | Late Embryo | Fetal | Postnatal | Abnormalities | Quiz | Online Assessment

Reproductive Abnormalities

Australian abnormalities 81-92 urogenital.jpg

This page introduces the statistical data associated with birth abnormalities in the genital system in Australia and also briefly introduces some of these defects. For more detailed coverage look at the Genital Abnormalities Notes. Abnormalites associated with development of secondary sex characteristics including mammary development are not covered in this current practical class.


Note that some abnormalites affect physiological function, while others through mainly perturbed endocrine effects, can impact upon not only other systems but also have neurological ramifications upon sexual identity. Then finally look at the online information provided to the general public on birth defects associated with genital system development and sexuality.

Genital abnormalities fall into several categories: chromosomal, intersex, gonadal dysfunction, tract abnormalities, external genitalia and gonadal descent.

Links: Genital System - Abnormalities

Critical Periods

Human- genital development critical periods.jpg

Gonadal Descent

Cryptorchidism.jpg Cryptorchidism
  • an abnormality of either unilateral or bilateral testicular descent
  • occurring in up to 30% premature and 3-4% term males
  • Descent may complete postnatally in the first year, failure to descend can result in sterility.
Male - inguinal hernia.jpg Hernia
  • Indirect inguinal hernia is a common condition in male infants
  • resulting from a patent processus vaginalis
  • allowing communication between the peritoneal cavity and the scrotal sac
  • through which portions or loops of small intestine may herniate.
  • This is a common surgical repair operation in young children.

Hydrocele

  • a fluid-filled cavity of eiter testis or spermatic cord, where peritoneal fluid passes into a patent processus vaginalis.
  • Hydrocele of the testis is when a very small patent processus vaginalis may not herniate, but allow fluid to pass from the periotoneal cavity leading to the collection of serous fluid between the layers of the membrane (tunica vaginalis).
    • Normal - fluid around the testicle is absorbed
    • Noncommunicating hydrocele - fluid remains around the testicle
    • Communicating hydrocele - fluid flows back and forth between the scrotum and the abdomen
    • Hydrocele of the cord - fluid is located between the scrotum and the abdomen

External Genitalia

Hypospadia classifications.jpg Hypospadia
  • most common penis abnormality (1 in 300)
  • a failure of male urogenital folds to fuse in various regions
  • resulting in a proximally displaced urethral meatus.
  • cause is unknown, but suggested to involve many factors either indivdually or in combination including: familial inheritance, low birth weight, assisted reproductive technology, advanced maternal age, paternal subfertility and endocrine-disrupting chemicals. Infants with hypospadias should not undergo circumcision.

Opening of the urethra (meatus) on the inferior surface (ring) not at the tip. Other regions where urethra may open to the surface (dashed line).


Links: Genital System - Abnormalities

Internal Genitalia

Male

  • Ductus Deferens - unilateral or bilateral absence congenital unilateral absence of the vas deferens (CUAVD), Congenital bilateral absence of the vas deferens (CBAVD)

failure of mesonephric duct to differentiate frequent cause of obstructive azoospermia 75% of men with bilateral absence have at least one detectable common mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene

Female

Uterine abnormalities.jpg A range of uterine and vaginal anatomical anomalies based upon the abnormal development and fusion of the paramesonephric ducts and vaginal development.
  • Uterine Duplication (uterus didelphys, double uterus, uterus didelphis) A rare uterine developmental abnormality where the paramesonephric ducts (Mullerian ducts) completely fail to fuse generating two separate uterus parts each connected to the cervix and having an ovary each. Failure of fusion of lower paramesonephric ducts, with either double or single vagina.
  • Unicornate Uterus - failure of the paramesonephric ducts to fuse. A single paramesomnephric duct has fused with the vaginal plate and now opens into the vagina, while the other forms a diverticulum.
  • Septate Uterus
  • Cervical - cervical agenesis, cervical duplication
  • Vagina Absence - Failure of sinovaginal bulb development, 1 in 4,000 to 5,000 female births.


Additional Information

Disorders of Sex Development

The previous human sex development terminology (true hermaphrodites, male pseudohermaphrodites and female pseudohermaphrodites) are considered outdated and stigmatising and have been replaced with the general term Disorders of Sex Development (DSD) established by the Consensus statement on management of intersex disorders.[1] See also the Medical Journal of Australia 2009 editorial article.[2]

Previous Terminology New Proposed Terminology
Intersex DSD
Male pseudohermaphrodite, undervirilization of an XY male, and undermasculinization of an XY male 46,XY DSD
Female pseudohermaphrodite, overvirilization of an XX female, and masculinization of an XX female 46,XX DSD
True hermaphrodite Ovotesticular DSD
XX male or XX sex reversal 46,XX testicular DSD
XY sex reversal 46,XY complete gonadal dysgenesis

Hypospadia

Hypospadia Classification Meatus Opening
Anterior on inferior surface of glans penis
Coronal in balanopenile furrow
Distal on distal third of shaft
Penoscrotal at base of shaft in front of scrotum
Scrotal on scrotum or between the genital swellings
Perineal behind scrotum or genital swellings
  • Epispadias - Uncommon abnormality associated with the penis, 1 in 30,000 infant males, external urethral opening on the dorsal surface of penis.
  • Cryptorchidism in common eutherian mammals.[3]- Species comparison of descent timeline
  • Mayer-Rokitansky syndrome (MRK anomaly, Rokitansky-Küster-Hauser syndrome, RKH syndrome, RKH) congenital absence of the vagina, dyspareunia, vaginal agenesis.

Polycystic Ovary Syndrome

(PCOS) or Stein–Leventhal syndrome (1930s researchers) a metabolic syndrome with many other symptoms, ovarian cysts arise through incomplete follicular development or failure of ovulation. For review see [4]

Environmental Abnormalities

  • Diethylstilbestrol (DES or diethylstilbetrol) - is a drug that was prescribed to women from 1938-1971 to prevent miscarriage in high-risk pregnancies.
    • The drug acted as a potent estrogen (mimics natural hormone) and therefore could also act as a potential endocrine disruptor.
    • This led to a number of developing fetal reproductive tract and other abnormalities.
  • In the female fetus, it increased risk of abnormal reproductive tract and also carcinogenic (cancer forming).
  • In the male fetus, it increased the occurance of abnormal genitalia.
  • The drug was banned by FDA (USA) in 1979 as a teratogen, it had previously also been used as livestock growth promoter and could have potentially entered the human food chain.

References

  1. <pubmed>16882788</pubmed>| Pediatrics.
  2. <pubmed>19485836</pubmed>| Med J Aust.
  3. <pubmed>17379650</pubmed>
  4. <pubmed>14748678</pubmed>


2011 Lab 8: Introduction | Sex Determination | Early Embryo | Late Embryo | Fetal | Postnatal | Abnormalities | Quiz | Online Assessment

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Cite this page: Hill, M.A. (2019, October 13) Embryology 2011 Lab 8 - Genital Abnormalities. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/2011_Lab_8_-_Genital_Abnormalities

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© Dr Mark Hill 2019, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G