Partial Androgen Insensitivity Syndrome Presenting as Ambiguous Genitalia in a 46,XY Infant
https://doi.org/10.15605/jafes.041.S1
- Author:
Muhammad Shafiq Safwan bin Md Latip
1
;
Shi Chyn Lim
1
;
Yee Lin Lee
1
Author Information
1. Department of Paediatrics, Faculty of Medicine and Health Science, Hospital Sultan Abdul Aziz Shah, Universiti Putra Malaysia
- Publication Type:Journal Article
- MeSH:
Male;
Infant;
Androgen-Insensitivity Syndrome
- From:
Journal of the ASEAN Federation of Endocrine Societies
2026;41(S1):141-
- CountryPhilippines
- Language:English
-
Abstract:
Introduction:Partial androgen insensitivity syndrome is a rare X-linked
46, XY disorder caused by androgen receptor dysfunction,
producing variable genital ambiguity and complex
diagnostic challenges in early infancy and childhood.
Case:We report a term infant, currently aged 9 months, who was
admitted to the Neonatal Intensive Care Unit at birth for
glucose-6-phosphate dehydrogenase (G6PD) deficiency
and noted to have ambiguous genitalia. The infant had
no hypoglycemia, feeding intolerance, or electrolyte
disturbances throughout admission. She is the second child
of non-consanguineous parents, with no family history of
disorders of sex development. Examination of the external
genitalia revealed a prominent phallus without erectile
tissue with mildly pigmented and rugated labioscrotal
folds. There was no labioscrotal fusion. Bilateral gonads
were palpable in both labioscrotal folds with one opening
seen.
Pelvic ultrasonography showed bilateral small testes within
the labioscrotal folds, with absence of Müllerian structures.
Karyotype analysis confirmed 46, XY genotype. Human
chorionic gonadotropin stimulation (HCG) testing at day
7 of life demonstrated normal baseline testosterone 4.9
nmol/L, but minimal testosterone rise 5.4 nmol/L at day
4 post HCG. Normal testosterone to dihydrotestosterone
ratio and testosterone to androstenedione ratio excluded
defects in androgen synthesis, while normal adrenal steroid
profile ruled out congenital adrenal hyperplasia.
Gonadotropin-releasing hormone stimulation at 2 months
old revealed a peak follicle-stimulating hormone of 8 IU/L
and peak LH of 4 IU/L. Anti-Müllerian hormone level was
markedly elevated >328 pmol/L (normal 5.5–103 pmol/L). Whole-exome sequencing identified a hemizygous
androgen receptor gene variant, p.(Pro818Ala), classified as
a variant of uncertain significance with deleterious in silico
predictions, consistent with X-linked partial androgen
insensitivity syndrome.
Conclusion:This case highlights the necessity of early, systematic
endocrine evaluation integrated with genomic testing in
46, XY DSD to achieve a definitive diagnosis, optimize
sex assignment, and guide longitudinal, multidisciplinary
management.
- Full text:2026081013405458556EP_P013.pdf
