Ovotesticular Disorder of Sexual Development Clinical Presentation

Updated: Jan 12, 2017
  • Author: Molina B Dayal, MD, MPH; Chief Editor: Richard Scott Lucidi, MD, FACOG  more...
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Presentation

History

The presence of both testicular and ovarian tissue within one individual gives rise to varying degrees of ambisexual development. The first contact with a patient with ovotesticular disorder of sexual development is in the newborn period. A newborn usually presents with ambiguous genitalia and discussions must be had with the parents to rule out immediately life-threatening diseases. Although some cases of OT-DSD are diagnosed in the newborn period, only 20% are diagnosed prior to age 5 years. Most cases of OT-DSD are diagnosed in the pubertal period when the young male begins to experience feminization. By puberty, most of the life-threatening conditions associated with genital ambiguity have been ruled out.

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Physical

A thorough physical examination is mandatory.

Newborn period: When faced with the delivery of an infant with genital ambiguity, the physician must determine if the newborn is a virilized female, an undermasculinized male, or a rare person with ovotesticular disorder of sexual development. Physical examination should focus on the following considerations:

  • Genetic stigmata: A general assessment of the infant's body habitus should be made, giving special attention to the presence of any genetic stigmata.
  • Skin pigmentation: Skin pigmentation pattern should be noted as areolar, and scrotal hyperpigmentation may be a manifestation of high serum adrenocorticotropic hormone (ACTH) levels associated with congenital adrenal hyperplasia (CAH). Skin mottling and heterochromia of the iris may be present in the rare person with chimeric hermaphroditism.
  • Genital examination: Determine the penile length and the location of the urethral opening, inspect the frenulum, determine the labioscrotal condition, document the number and location of perineal orifices, and identify the position of the gonads. One important clinical finding that may be present is a palpable gonad in one of the labioscrotal folds. If the newborn has OT-DSD, the palpated gonad is most likely an ovotestis or testis and usually is located on the right side. Discerning a difference between the ovarian (firmer) and testicular (softer) components of an ovotestis by palpation may be possible.

Pubertal period: Most cases of OT-DSD are diagnosed in the pubertal period when the young male begins to experience feminization. By puberty, most of the life-threatening conditions associated with genital ambiguity have been ruled out. Aside from the physical examination findings discussed in the newborn section, pay special attention to the following:

  • Sexual hair distribution: Adrenarche is a normal part of both male and female puberty. The absence of pubic and axillary hair suggests androgen insensitivity. Alternatively, a feminine sexual hair pattern in a pubescent male should trigger further investigation.
    • A case study of a 14-year-old female patient indicates that patients with 46 XX OT-DSD may present with virilization at puberty along with dysmorphic features. [5]
  • Uterus: In ovotesticular disorder of sexual development, the presence or absence of a uterus is variable. Anomalies are common when the uterus is present. A hemiuterus, uterine hypoplasia, and cervical atresia are the most frequent uterine anomalies noted. Approximately 60% of those individuals with a 46,XX peripheral karyotype menstruate or present with signs of obstructed genital outflow tract at puberty.
  • Vagina: The vagina, when present, is normal in only 9% of cases of ovotesticular disorder of sexual development. The vagina generally shares the urogenital sinus with the urethra as the common external orifice.
  • Phallus: The phallus, if present, is almost always in chordee. Phallic length varies greatly. The urethra most commonly opens as a urogenital sinus. Hypospadias, often associated with bifid scrotal folds, is the most common anomaly of the external genitalia encountered.
  • Labia/scrotum: The presence or absence of labioscrotal fusion is variable. In one review, 7% of people with true hermaphroditism had normal labia majora, 13% had hemiscrotum, 17% had a normal scrotum, and 63% had labioscrotal folds. Gonads were found frequently on the right side of the labioscrotal folds.
  • Breast development [6] : Most people with OT-DSD are given a male sex assignment at birth but develop breasts at puberty or later. Thelarche occurs in more than 90% of people with ovotesticular disorder of sexual development.
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Causes

Normal sexual differentiation is based on genetic sex (XX or XY), which is established at conception. Until 7 weeks of gestation, the fetus is sexually indifferent, internally developing both wolffian and mullerian ducts. Expression of sex-determining genes on the early bipotential gonad promotes development of the testis or ovary.

Various genes expressed by the Y chromosome at very specific times during development are responsible for the differentiation of the testes. A 35-kilobase (kb) gene determinant located on the distal short arm of the Y chromosome, known as the SRY (sex determining region of the Y chromosome) is responsible for initiating testes formation. SRY codes for a transcription factor that acts in the somatic cells of the genital ridge. The transient expression of this gene triggers a cascade of events that leads to the development of testicular Sertoli and Leydig cells. SRY expression directs testicular morphogenesis, characterized by the production of MIS (müllerian-inhibiting substance), and, later, testosterone.

Surprisingly, more than half of the patients with XX ovotesticular disorder of sexual development lack SRY, despite the presence of testicular differentiation. This suggests that this gene codes for a product that reacts with other genes on Y, X, and/or autosomes to complete testicular differentiation. Research has looked at SRY-related high mobility box 9 (SOX9) gene, located on autosomal chromosome 17, as a contributor to Sertoli cell differentiation. Increased expression of SOX9 is being studied as a cause for female-to-male sex reversal in 46,XX SRY negative people with ovotesticular disorder of sexual development. Recently, an inactivating mutation of SOX9 was shown to be associated with autosomal sex reversal and camptomelic dysplasia.

The DAZ (deleted in azoospermia) gene family consists of a cluster of genes on the Y chromosome that give rise to proteins that influence male germ cell differentiation. In humans, deletion of any 1 of 3 DAZ regions (ie, AZFa, AZFb, AZFc) disrupts spermatogenesis. Today, deletion of the AZFc region of the Y chromosome is the most frequent molecularly defined cause of spermatogenic failure.

In 46,XY males, the Sertoli cells of the testes are responsible for the production of mullerian-inhibiting substance, which causes regression of the mullerian ducts. The Leydig cells then produce testosterone, which promotes the development of the epididymis, vas deferens, and seminal vesicles.

For the fetus exposed to only the X chromosome, female gonadal development ensues. Ovarian differentiation appears to rely on a mechanism that is triggered mostly, but not solely by the absence of the testicular determinant. Female development is no longer viewed as only a default pathway for reproductive differentiation. In humans, a complete 46,XX chromosomal complement is necessary for normal ovarian differentiation. Autosomal genes also appear to be involved in ovarian maintenance. Properties of the X-linked gene DAX1 (Dose sensitive sex reversal locus on X chromosome, gene 1) suggest that this gene is important in ovarian determination. Investigators have postulated that the DAX1 gene product may actually be an anti-testes factor and may be antagonistic to the action of SRY. [7] An additional signaling molecule, Wnt4, is found in mullerian ducts and contributes to the development of female internal genitalia.

Internal genitalia of the female fetus develop if there is no exposure to the SRY gene and its signaling molecules. The wolffian duct regresses and the mullerian duct then matures into the oviduct, uterus, cervix, and upper vagina.

Hormone expression during the 9th week of gestation, from the testes or ovary, stimulates external genitalia development. By the 14th week of gestation the external genitalia have been formed. During the developmental process, there are multiple opportunities for errors in differentiation, all of which have been theorized as possible causes of the ovotesticular disorder of sexual development.

In humans, genetic sex has traditionally been evaluated through establishing the karyotype of peripheral lymphocytes. However, the peripheral karyotypes of patients with OT-DSD show marked variation. Approximately 60% are 46,XX; 15% are 46,XY; and 25% show various forms of mosaicism. Less than 1% show 46,XX/46,XY chimerism or the existence of 2 or more cell lines, each of which has a different genetic origin.

Therefore, ovotesticular disorder of sexual development is a genetically heterogeneous condition. Phenotypic, gonadal, and molecular studies have led to several causation theories:

  • Genetic chimerism: Fewer than 1% of people with OT-DSD have 46,XX/46,XY chimerism or the existence of 2 or more cell lines, each of which has a different genetic origin. Chimerism can result from several events.
    • Dispermic chimerism (double fertilization) can arise from fertilization of the secondary oocyte and first polar body, fertilization of the ovum and the first polar body, or fertilization of the ovum and the second polar body.
    • Chimerism can also arise as an exchange of cells between dizygous twins of different sex (ie, fusion of 2 embryos).
  • Nondisjunction: Postzygotic mitotic errors arising from anaphase lag may occur in 45,X/46,XY or 45,X/46,XY/47,XYY mosaicism. Note, however, that most 45,X/46,XY individuals have mixed gonadal dysgenesis as opposed to true hermaphroditism.
  • X-Y translocation: Paternal meiotic exchange between the pseudoautosomal regions of chromosomes X and Y could provide a mechanism for the translocation Y-chromosomal sequences, including SRY onto an X chromosome in some forms of 46,XX testicular differentiation.
  • Mutation: A mutation of a gene on the X chromosome or alternatively on an autosome that allows testis determination without the SRY gene could explain some forms of 46,XX testicular differentiation. In addition, some 46,XX with OT-DSD have been observed to have a translocation of SRY onto the X chromosome. However, most individuals with ovotesticular disorder of sexual development with 46,XX are SRY negative.
  • Occult mosaicism: Although most people with OT-DSD have a 46,XX peripheral karyotype, recent case reports have documented the detection of occult mosaicism in the gonads of some of these individuals through molecular techniques. Polymerase chain reaction (PCR) has identified SRY -positive tissue in gonads from several, but not all, people with 46,XX ovotesticular disorder of sexual development.

Mutation of downstream autosomal genes involved with testicular differentiation and mutation/duplication or deletion of an X-linked locus may explain SRY –negative ovotesticular disorder of sexual development.

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