BGDB Sexual Differentiation - Abnormalities

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Practical 12: Sex Determination | Early Embryo | Late Embryo | Fetal | Postnatal | Abnormalities | 2011 Audio


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 Duplication, Unicornate Uterus, Septate Uterus.

Uterine anomalies ESHRE-ESGE classification.jpg

This cartoon shows the new 2013 ESHRE-ESGE classification system [1] based on uterine anatomy, embryological origin is the secondary basic characteristic, and both cervical and vaginal anomalies are classified in independent co-existent sub-classes. For more detail see Additional Information.


  • Cervical - cervical agenesis, cervical duplication
  • Vagina Absence - Failure of sinovaginal bulb development, 1 in 4,000 to 5,000 female births.

Other Abnormalities

Use the links to find out more about these topics.

  • Congenital Adrenal Hyperplasia - impairment of cortisol production by the adrenal cortex, is one of the most common causes of intersex genitalia at birth.
  • Androgen Insensitivity Syndrome - genetically male (XY) unable to respond to male sex hormones (androgens), they may have mostly female sex characteristics or signs of both male and female sexual development. Also a partial androgen insensitivity syndrome (PAIS) associated with impaired male genital development that can be transmitted through mutations in the androgen receptor.
  • Cryptorchidism - covered in detail above.
  • Undescended Ovaries - reasonably rare gonad abnormality, often detected following clinical assessment of fertility problems and may also be associated with other uterine malformations (unicornuate uterus).
  • Hydrocele - most commonly male (but can be female) fluid-filled cavity.


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Practical 12: Sex Determination | Early Embryo | Late Embryo | Fetal | Postnatal | Abnormalities | 2011 Audio




Additional Information

Additional Information - Content shown under this heading is not part of the material covered in this class. It is provided for those students who would like to know about some concepts or current research in topics related to the current class page.

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.[2] See also the Medical Journal of Australia 2009 editorial article.[3]

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.[4]- 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.

Uterine Anomalies

Uterine anomalies ESHRE-ESGE classification.jpg
Classification of Uterine Anomalies ESHRE/ESGE
Uterine anatomy is the basis of the new 2013 system.[1] Embryological origin has been adopted as the secondary basic characteristic in the design of the main classes. Cervical and vaginal anomalies are classified in independent co-existent sub-classes.


  • Class U0 - incorporates all cases with normal uterus.
  • Class U1 - (Dysmorphic uterus) incorporates all cases with normal uterine outline but with an abnormal shape of the uterine cavity excluding septa. Class I is further subdivided into three categories
    • Class U1a - (T-shaped uterus) characterized by a narrow uterine cavity due to thickened lateral walls with a correlation 2/3 uterine corpus and 1/3 cervix,
    • Class U1b - (uterus infantilis) characterized also by a narrow uterine cavity without lateral wall thickening and an inverse correlation of 1/3 uterine body and 2/3 cervix
    • Class U1c - (others) which is added to include all minor deformities of the uterine cavity including those with an inner indentation at the fundal midline level of less than 50 % of the uterine wall thickness.
  • Class U2 - (septate uterus) internal indentation >50 % of the uterine wall thickness & external contour straight or with indentation <50 %
    • Class U2a - (partial septate uterus) characterized by the existence of a septum dividing partly the uterine cavity above the level of the internal cervical os
    • Class U2b - (complete septate uterus) characterized by the existence of a septum fully dividing the uterine cavity up to the level of the internal cervical os.
  • Class U3 - (bicorporeal uterus) external indentation >50 % of the uterine wall thickness
    • Class U3a - (partial bicorporeal uterus) characterized by an external fundal indentation partly dividing the uterine corpus above the level of the cervix
    • Class U3b - (complete bicorporeal uterus) width of the fundal indentation at the midline >150 % of the uterine wall thickness) completely dividing the uterine corpus up to the level of the cervix
    • Class U3c - (bicorporeal septate uterus) characterized by the presence of an absorption defect in addition to the main fusion defect.
  • Class U4 - (hemi-uterus) incorporates all cases of unilateral formed uterus. Hemi-uterus is defined as the unilateral uterine development; the contralateral part could be either incompletely formed or absent.
    • Class U4a - (hemi-uterus with a rudimentary (functional) cavity) characterized by the presence of a communicating or non-communicating functional contralateral horn
    • Class U4b - (hemi-uterus without rudimentary (functional) cavity) characterized either by the presence of non-functional contralateral uterine horn or by aplasia of the contralateral part.
  • Class U5 - (aplastic uterus) incorporates all cases of uterine aplasia, formation defect characterized by the absence of any fully or unilaterally developed uterine cavity.
    • Class U5a - (aplastic uterus with rudimentary (functional) cavity) characterized by the presence of bi- or unilateral functional horn
    • Class U5b - (aplastic uterus without rudimentary (functional) cavity) characterized either by the presence of uterine remnants or by full uterine aplasia.
  • Class U6 - is kept for still unclassified cases.
  • 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

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 [5]

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. ↑ 1.0 1.1 <pubmed>23894234</pubmed>| PMC3718988 | Gynecol Surg.
  2. ↑ <pubmed>16882788</pubmed>| Pediatrics.
  3. ↑ <pubmed>19485836</pubmed>| Med J Aust.
  4. ↑ <pubmed>17379650</pubmed>
  5. ↑ <pubmed>14748678</pubmed>



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Cite this page: Hill, M.A. (2024, May 17) Embryology BGDB Sexual Differentiation - Abnormalities. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/BGDB_Sexual_Differentiation_-_Abnormalities

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© Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G
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