An infant with 49XXXXY syndrome: a case report.

Background: 49XXXXY syndrome is the rarest X chromosome aneuploidy, with approximate incidence of 1:85,000-100,000 male births. Worldwide, around 100 cases have been reported. In this report, we describe one such case seen in Sri Lanka.

Case Presentation: A 10-day-old Sri Lankan neonate born in a tertiary care center was referred to the pediatric endocrinology unit of Lady Ridgeway Hospital due to detection of ambiguous genitalia at birth. He was the first child born to nonconsanguineous healthy parents following an uncomplicated antenatal period. He was born at term via normal vaginal delivery, with a birth weight of 2.385 kg. The baby was active, and there was no documented hypoglycemia or alteration in basic biochemical investigations. On examination, the child had hypertelorism, upslanting palpebral fissures, flat occiput, and mild webbing of the neck. System examination was normal. Genitalia examination revealed bifid scrotum, perineal urethra, 2 cm phallus, and bilateral testis in situ. Hormonal analysis, including dehydroepiandrosterone sulfate, testosterone, and 17-OH progesterone levels, was normal except for an elevated level of follicle-stimulating hormone, indicating gonadal dysgenesis. Ultrasound of the abdomen detected testis located at bilateral inguinal canal, and no Müllerian structures were visible. Echocardiography showed a small patent foramen ovale with otherwise normal heart. Chromosome analysis revealed 49XXXXY syndrome.

Conclusion: 49XXXXY syndrome should be entertained as a rare possibility for ambiguous genitalia, and karyotyping is an essential investigation for evaluation of such patients.