A single-center, observational study of 607 children & young people presenting with Differences in Sex Development (DSD)

Context
Differences in sex development (DSD) represent a wide range of conditions presenting at different ages to various health professionals. Establishing a diagnosis, supporting the family and developing a management plan are important.

Objective
We aimed to better understand the presentation and prevalence of pediatric DSD.

Design
A retrospective, observational cohort study was undertaken of all children and young people (CYP) referred to a DSD multi-disciplinary team over 25 years (1995-2019).

Setting
A single tertiary paediatric center.

Participants
In total, 607 CYP (520 regional referrals) were included.

Main Outcome Measures
Data were analyzed for diagnosis, sex-assignment, age and mode of presentation, additional phenotypic features, mortality, and approximate point prevalence.

Results
Amongst the three major DSD categories, sex chromosome DSD was diagnosed in 11.2% (68/607) (most commonly 45, X/46, XY mosaicism), 46, XY DSD in 61.1% (371/607) (multiple diagnoses often with associated features), while 46, XX DSD occurred in 27.7% (168/607) (often 21-hydroxylase deficiency). Most children (80.1%) presented as neonates, usually with atypical genitalia, adrenal insufficiency, undescended testes or herniae. Those presenting later had diverse features. Rarely, the diagnosis was made antenatally (3.8%, n = 23) or following incidental karyotyping/family history (n = 14). Mortality was surprisingly high in 46, XY children, usually due to complex associated features (46, XY girls, 8.3%; 46, XY boys, 2.7%). The approximate point prevalence of neonatal referrals for investigation of DSD was 1 in 6,347 births, and 1 in 5,101 overall throughout childhood.

Conclusions
DSD represent a diverse range of conditions that can present at different ages. Pathways for expert diagnosis and management are important to optimize care.