Ambiguous Genitalia

• Infants born with ambiguous genitalia or intersex conditions (when the sex of a newborn infant is uncertain from examination of the external genitalia) present a challenge to diagnosis but also to broader aspects of management.¹
• In most cases a prompt diagnosis and therapeutic options can be presented to parents.²
• The psychological and social implications of gender assignment and treatments are important. The impact of anything other than an unambiguous answer to parents at birth asking the sex of their baby encapsulates the importance of good management.
• It is important that such cases are managed with knowledge, experience, expedition, explanations and psychological support. However research shows that development of gender identity begins in utero and in some cases surgical genital reconstruction should be done with less haste.³

It is essential in management and diagnosis of intersex disorders and ambiguous genitalia to understand normal sexual determination and differentiation.¹ Chromosomal sex prescribes gonadal sex which in turn prescribes the phenotypic sex. The gonad type determines whether the Mullerian or Wolffian ducts develop or regress. Gender identity is affected by prenatal and postnatal brain development and not just by phenotypic appearance.

• Male and female embryos develop in a similar manner until 6-7 weeks of gestation
• In the presence of a Y chromosome the undifferentiated gonad develops into a testis and in the absence it develops into an ovary. The genetic information for this to happen is held on the short arm of the Y chromosome (the sex determining region or SRY). In the absence of this region the gonad develops into an ovary. However other genes are important as demonstrated by the existence of XX males with testicular tissue without the SRY.
• The primitive gonad develops from primordial germ cells from posterior endoderm of the yolk sac.
  • With Y chromosome primitive seminiferous tubules develop in the centre of the gonad. Fetal pituitary LH and placental HCG encourage fetal leydig cells to develop and produce testosterone.
  • In the absence of a Y chromosome the germ cells undergo mitotic and meiotic divisions to form oocytes. These become surrounded by a layer of granulosa cells and are called primordial follicles. These are some 7 million in number at the 20th to 25th week of gestation. With the surge of fetal pituitary FSH the first primary follicles are formed.
• Differentiation of genital ducts.
  • Around the 4th week of gestation 2 substances, testosterone and antimullerian hormone (AMH) are critical for male differentiation of the genital ducts. The testosterone induces primordial wolffian (mesonephric) duct to become epididymis, vas deferens and seminal vesicle. High local levels of testosterone are needed to achieve this. AMH is produced by Sertoli cells of the testis and this suppresses passive development of Mullerian ducts (into upper third of vagina, uterus and fallopian tubes). Testosterone may enhance the AMH inhibition.
  • In females, the wolffian ducts disappear and the mullerian ducts develop into upper third of vagina, uterus and fallopian tubes. Exposure to androgens does not affect this and neither does the presence or absence of ovaries.
• Differentiation of external genitalia. The external genitalia of males and females are identical in the first 7 weeks of gestation.
  • In males from 7 weeks active differentiation towards the male phenotype occurs moderated by testosterone and its conversion to dihydrotestosterone (DHT) by 5- α reductase (present in the cells of external genitalia and urogenital sinus). Genital tubercle becomes glans. Fusion of urethral folds and groove forms shaft of penis. Labioscrotal swellings fuse and enlarge to become scrotum.
  • In the female genital tubercle becomes clitoris, labioscrotal swellings the labia majora and urethral folds the labia minora. The urogenital sinus forms lower 2/3 of the vagina.
• Testosterone related development begins at 6 weeks gestation coinciding with surge in LH but after about 14 weeks testosterone levels are dependent on placental HCG. The consequent foetal levels of testosterone help growth of phallus, scrotum and testicular descent. Micropenis and cryptorchidism result from congenital gonadotrophin deficiency.

Ambiguous genitalia are caused by a variety of different conditions which vary greatly in incidence. Genital anomalies are estimated to occur in 1 in 4500 births.⁴The most common cause of ambiguous genitalia in the newborn is congenital adrenal hyperplasia (CAH)^5,3 (1 per 15,000 live births). CAH appears to be more common in those of European Jewish, Hispanic, Slavic and Italian descent. Mixed gonadal dysgenesis (MGD) is the next most common cause. Hypospadias is quite common (1 in 300 live births) but in less than 1% of such cases is this combined with undescended testes. It is estimated that 50% of infants with hypospadias and unilateral or bilateral cryptorchidism will have an intersex condition.^6,3

To make a diagnosis it is essential not only to understand normal development but also to understand the different pathophysiological mechanisms responsible for intersex conditions. Different classifications are used.
The traditional classification of intersex conditions puts more emphasis on the presenting features:

• Female pseudohermaphrodite (2 ovaries). 46XX karyotype, normal ovaries and female internal genitalia with varying degrees of external virilisation (CAH is the most common cause and different enzyme defects are responsible);
• Male pseudohermaphrodite (2 testes). 46XY karyotype and testes but inadequate masculinisation of either genital ducts or external genitalia or both. This is caused by deficiency of müllerian-inhibiting substance (MIS), deficient testosterone biosynthesis, androgen insensitivity and 5 α-reductase deficiency;
• True hermaphrodite (ovary and/ or testes and/ or ovotestis). This is uncommon as a cause of ambiguous genitalia (10% of intersex cases);
• Mixed gonadal dysgenesis (testis plus streak gonad);
• Pure gonadal dysgenesis (bilateral streak gonads).

However this classification has been deemed unhelpful to management by some²and abandoned in favour of a classification which highlights the underlying pathophysiology:

• Virilised females.
  • Virilisation by androgens of fetal origin. This may be from congenital adrenal hyperplasia or persistent fetal adrenocortical steroids.
  • Virilisation by androgens of maternal origin. These may be from drugs (anabolic steroids, testosterone, danazol, progestogens etc), tumours (ovary or adrenal) or maternal CAH.
  • Dysmorphic syndromes (e.g. Beckwith-Wiedemann, Seckel, Zellweger)
  • Local abnormalities (e.g. lipomas, neurofibromatosis)
  • Idiopathic
• Inadequately virilised males.
  • Leydig cell agenesis or hypoplasia
  • LH deficiency
  • Inborn errors of testosterone biosynthesis. These may affect testes and adrenal glands (e.g. cholesterol side chain cleavage deficiency, 3 β -hydroxysteroid dehydrogenase deficiency, 17 α -hydroxylase deficiency) or just testes (e.g. 17,20-lyase deficiency)
  • Target tissue defects. This includes defects in testosterone metabolism (e.g. 5 α -reductase deficiency) or androgen receptor defects.
  • Persistent Mullerian duct syndrome. AMH deficiency will cause this.
  • Dysmorphic syndromes such as Dubowitz, Smith-Lemli-Opitz etc.
• Disorders of gonadal differentiation. The role of the testis in development of internal and external genitalia means that dysgenetic gonads produce combinations of abnormalities of internal and external genitalia. Examples include:
  • Gonadal dysgenesis. Patients often have XO (often with mosaicism, e.g. Turner's syndrome)) or XY karyotypes and present has females with amenorrhoea.
  • Mixed gonadal dysgenesis. May have typically a testes palpable (inguinal or scrotal) with perineal hypospadias. On the side of testes (ipsilateral) wolffian structures, absent mullerian but mullerian and absent wolffian same side as streak gonad.
  • 'Vanishing testes syndrome' or anorchia. Boys presenting with normal male genitalia and bilateral cryptorchidism who must have had testicular function in the foetal period.
  • True hermaphrodites. Well-developed ovarian and testicular tissues are found in either the same or opposite gonads. Genital duct development is according to the ipsilateral gonad. Can present with ambiguous genitalia or at puberty.

Team effort is required in diagnosis and this begins with taking time to take a detailed history. The process of diagnosis should follow an orderly process and jumping to conclusions should be avoided.² The most commonly seen condition will be the virilised 46,XX female with CAH and often the challenge is to identify less common causes. There is a strong possibility of misdiagnosis and gender misassignment particularly with CAH where virilisation can be extreme.

History

• Mother: medication history, particularly if signs of virilisation in the mother. A history of unexplained early or neonatal deaths may indicate missed adrenogenital deficiency.
• Family history suggesting a genetically transmitted trait, for example of:
  • Ambiguous genitalia
  • Infertility
  • Primary amenorrhoea
  • Late puberty
  Recessive traits will tend to occur in siblings and X-linked abnormalities will be seen in males scattered across the family tree.

Examination

Broadly this should include:

• A search for other congenital abnormalities
• Identification of dysmorphic features
• Careful examination external genitalia (size of phallus, degree of differentiation e.g. Prader stages, clitoromegaly, hypospadias, position of meatus). Labioscrotal folds may be fused to give the appearance of a scrotum and be rugose or pigmented in adrenogenital syndrome.
• Examination of gonads. Careful examination of the labioscrotal folds, which usually identifies testicular material although ovotestes may descend as well. The inguinal regions should also be carefully examined for gonads
• Rectal examination may identify cervix and uterus.

Workup may include a variety of tests. In practice one of the most important is pelvic ultrasound. If a uterus is present the baby is almost certainly a virilised female and most likely to have CAH. If the uterus is absent the diagnosis is likely to be more difficult.

• Laboratory studies
  • Chromosomal analysis for karyotype. Rapid karyotyping from buccal smears takes less than 24 hours as compared to 5 days for chromosome analysis.
  • Endocrine screening:
    • testosterone, androstenedione, DHT, DHEA, 17 alpha-hydroxyprogesterone
    • LH, FSH
    • ACTH, renin, aldosterone etc.
  • Electrolytes, urea and creatinine
  • Androgen receptor levels
  • 5-alpha reductase levels
• Imaging:
  • Pelvic/renal/bladder ultrasound. Adrenal glands may be seen to be enlarged. Virilisation with a uterus makes CAH likely.
  • Genitography. This helps define ductal anatomy.
  • CT and MRI scanning are not usually necessary but can further help identify anatomy.
• Other procedures include laparotomy or laparoscopy with or without gonadal biopsy. This can differentiate ovaries, testes, ovotestes and streak gonads.

Urine tests for steroid excretion, stimulation tests and other invasive tests are rarely needed.

• This should be made with great care and after proper diagnostic workup.¹ Despite thorough investigation definite final diagnosis cannot always be made.⁵
• Referral and consultation between specialties (for example: gynaecology; urology; endocrinology; genetics; surgery; psychiatry) is often important.²³

The range of possibilities is considerable and can be appreciated from the classification of the causes of ambiguous genitalia.

Prompt referral is essential.

Gender assignment

• Parents should be advised to delay registering the birth (It can be legally difficult to alter later) and naming the baby, until sex of rearing is decided.
• This should be done after completion of the diagnostic process, including full clinical, genetic and biochemical investigation.
• It should be done without delay and undue haste.
• It should be done involving the parents in full discussion and explanation.
• The assignment should aim to offer the best opportunity for normal puberty and sex life with unambiguous, functionally normal external genitalia and occasionally reproductive capability.

When considering the male gender the size of the penis is important but so is the potential to grow. It is important to establish the potential for growth with a trial of testosterone. Finding out later (at puberty) that androgen insensitivity prohibits masculinisation is to be avoided.
It is important to identify virilised females particularly where virilisation is extreme as it can be for example in CAH.

Emergency treatment

CAH can present with adrenocortical crisis, hyponatraemia or hypoglycaemia and emergency treatment of these complications is required.⁵ Monitoring for this (e.g. weight, potassium, glucose) is important.²

Long term management

As well achieving early diagnosis and emergency treatment of complications, there are longer term aspects to management which will vary according to the condition. CAH requires long term care for example.

• Medical care. Supplemental hormone therapy may be required if gonadal function is inadequate.
• Surgical treatment may be required. For example for hypospadias in males. In virilised females vaginoplasty and clitoroplasty may be required. Gender reassignment for example in male psudohermaphrodites with genital inadequacy may require surgery (multiple procedures). Gonadectomy may be advisable for patients with dysgenetic or non-functional gonads because of the risk of malignant change.
• Psychological support. Families will need intensive support, full explanations and information. This helps bonding with their child and probably the development of the child.

Incorrect gender assignment can produce obvious problems, particularly those associated with gender reassignment. Full discussion and explanation of the diagnosis often avoids medicolegal difficulties.³ There is controversy surrounding gender assignment particularly where genital surgery is involved. In the USA intersex activists have called for a moratorium on gender assignment until long term studies (e.g. North American Task Force on Intersexuality) have been completed. It has been said that the most important sex organ is the brain.³