Disorders of Sex Development (DSD)

Sex Development or Sexual differentiation is a complex but well orchestrated process which starts at 7-8 weeks of pregnancy in the developing fetus and is practically complete by 12 weeks. Any interference or disturbance in this orderly set of events can results in reproductive organs not being properly formed- called Disorders of Sexual Differentiation (erstwhile known as Intersex). DSD was coined by International Consensus Conference on Intersex organized by the Lawson Wilkins Pediatric Endocrine Society and the European Society for Pediatric Endocrinology in 2006. It replaces the earlier term Intersex which was thought to be controversial as there was a lot of social stigma attached with it and it was insensitive towards the families and kids suffering from DSD.

New molecular research, better understanding, long term follow-up data and better surgical techniques have allowed us to offer a more comprehensive approach including counseling, planned surgical correction and appropriate gender assignment in these babies.

  • How does normal Sex Development occur?
  • What are the types of DSD?
  • What are the tests for confirming DSD?
  • How are DSD treated?
  • Case a : Hyperlinks to case 16
  • Case b- Hyperlink to case 17

How does normal Sex Development occur?

Sex Development occurs under the guidance of chromosomes and genes encoded on them. Chromosomes reside in the nucleus of all of our cells and contain all the information necessary for our body structure & function. Human beings have 46 chromosomes (23 pairs) in all of their cells, 23 of these come from mother and 23 from father. 22 of these pairs are called Autosomes and one pair is called Sex chromosomes.

Female sex chromosome pair is configured anatomically as 46XX while in males as 46XY. The Y chromosome in males carries a region called SRY which guides the germ cells towards differentiation into male sex. First step in males is differentiation of germ cells into into testis while in the absence of Y chromosome in females the germ cells differentiate into ovary.

Testis liberates two hormones starting in week 8 which spearhead the differentiation. First one is called Mullerian Inhibiting substance which causes regression of female sex organs. Second one is called Testosterone which leads to development of male reproductive organs. Testosterone is further broken down into a hormone called Dihydrotestosterone and together with testosterone helps in formation of penis and external sex organs in male. Testosterone & Dihydrotestosterone are collectively called Androgens.

When is DSD suspected?

In neonatal age/ childhood

  • Ambiguous genitalia – on external examination there is a doubt.
  • Hypospadias with undescended testis
  • Severe Hypospadias
  • Micropenis
  • Clitoral hypertrophy/ posterior labial fusion
  • Inguinal hernia in a girl child

Older children & adults

  • Delayed or incomplete puberty
  • Primary amenorrhea
  • Infertility
  • Breast development in a male
  • Cyclical hematuria in a male

What are the types of DSD?

We are following the latest DSD classification formulated by International Consensus Conference on Intersex organized by the Lawson Wilkins Pediatric Endocrine Society and the European Society for Paediatric Endocrinology, 2006.

  • 46XY DSD – earlier called Male pseudohermaphrodite, undervirilised male, includes
    • Disorders of testicular development – Complete dysgensis (Swyer syndrome), Partial dysgenesis, gonadal regression
    • Disorders of Androgen Synthesis or action-
      • Androgen biosynthetic defect (17OH steroid dehydrogenase deficiency pr 5Alpha reductase deficiency)
      • Androgen Receptor defect: Partial or Complete Androgen insensitivity syndrome
      • Leydig cell aplasia
      • Persistent Mullerian duct syndrome
  • 46 XX DSD- earlier called female pseudohermaphrodite, virilised female
    • Disorders of ovarian development
    • Androgen excess
  • Sex chromosome DSD
    • Ovotesticular DSD – includes Mixed gonadal dysgenesis and some cases of True hermaphrodite
    • 46XX testicular DSD- Earlier called XX male or XX sex reversal
    • 46XY Complete gonadal dysgenesis – earlier called XY sex reversal
    • 47XXY- Klinefelter syndrome
    • 45XO – Turner Syndrome

What are the tests for confirming DSD?

After a thorough clinical examination and on the basis of suspected type of DSD, tests are done to confirm and reach a definitive & precise diagnosis. Not all the tests are required in all the cases, your doctor will be the best person to decide which tests to be done.

  • Ultrasound
  • 17-OH progesterone
  • Karyotype – is the study of chromosomes, done via blood tests
  • Hormonal assay- Testosterone/ Dihydrotestosterone/ LH/FSH/Estradiol etc
  • Retrograde genitogram
  • MRI pelvis
  • Levels of adrenal metabolites

How are DSD treated?

  • Counseling
  • Sex assignment
  • Sex assignment surgery if required
  • Psychosocial rehabilitation
  • Hormonal replacement

 



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