Challenges in clinical and laboratory diagnosis of androgen insensitivity syndrome: a case report
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2011
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Introduction: Androgen is a generic term usually applied to describe a group of sex steroid hormones. Androgens
are responsible for male sex differentiation during embryogenesis at the sixth or seventh week of gestation,
triggering the development of the testes and penis in male fetuses, and are directed by the testicular determining
factor: the gene SRY (sex determining region on Y chromosome) located on the short arm of chromosome Y. The
differentiation of male external genitalia (penis, scrotum and penile urethra) occurs between the 9th and 13th
weeks of pregnancy and requires adequate concentration of testosterone and the conversion of this to another
more potent androgen, dihydrotestosterone, through the action of 5a-reductase in target tissues.
Case presentation: This report describes the case of a teenage girl presenting with a male karyotype, and aims to
determine the extension of the mutation that affected the AR gene. A Caucasian girl aged 15 was referred to our
laboratory for genetic testing due to primary amenorrhea. Physical examination, karyotype testing and molecular
analysis of the androgen receptor were critical in making the correct diagnosis of complete androgen insensitivity
syndrome.
Conclusions: Sex determination and differentiation depend on a cascade of events that begins with the
establishment of chromosomal sex at fertilization and ends with sexual maturation at puberty, subsequently
leading to fertility. Mutations affecting the AR gene may cause either complete or partial androgen insensitivity
syndrome. The case reported here is consistent with complete androgen insensitivity syndrome, misdiagnosed at
birth, and consequently our patient was raised both socially and educationally as a female. It is critical that health
care providers understand the importance of properly diagnosing a newborn manifesting ambiguous genitalia.
Furthermore, a child with a pseudohermaphrodite phenotype should always undergo adequate endocrine and
genetic testing to reach a conclusive diagnosis before gender is assigned and surgical interventions are carried out.
Our results show that extreme care must be taken in selecting the genetic tools that are utilized for the diagnosis
for androgen insensitivity syndrome.
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MELO, Caroline O. A.; SILVA, Daniela M.; CRUZ, Aparecido D. da. Challenges in clinical and laboratory diagnosis of androgen insensitivity syndrome: a case report. Journal of Medical Case Reports, London, v. 5, e446, 2011.