An infant with 49XXXXY syndrome: a case report

Area of Science:

• Genetics
• Endocrinology
• Pediatrics

Background:

• 49XXXXY syndrome is an extremely rare X chromosome aneuploidy, with an incidence of 1:85,000-100,000 male births.
• Approximately 100 cases have been reported globally, underscoring its rarity.

Observation:

• A 10-day-old Sri Lankan neonate presented with ambiguous genitalia.
• Clinical examination revealed dysmorphic features including hypertelorism and mild neck webbing.
• Genital examination showed a bifid scrotum, perineal urethra, small phallus, and bilateral testes in situ.

Findings:

• Hormonal analysis indicated gonadal dysgenesis with elevated follicle-stimulating hormone.
• Abdominal ultrasound confirmed bilateral inguinal testes without Müllerian structures.
• Karyotyping definitively diagnosed 49XXXXY syndrome.

Implications:

• This case highlights 49XXXXY syndrome as a rare differential diagnosis for ambiguous genitalia in neonates.
• Karyotyping is essential for the accurate evaluation and diagnosis of such complex cases.
• Early diagnosis facilitates appropriate management and genetic counseling.