Background: Disorders of sex development (DSD) are a group of rare conditions characterized by variable discordance between chromosomal, gonadal and phenotypic sex. An association between smallness-for-gestational age (SGA) and DSD is already recognised, but few studies have investigated this in detail.
Aim of study: To evaluate the prevalence of SGA, among patients with DSD and to establish a correlation with the different types and causes of DSD.
Patients and methods: All patients referred for DSD to our endocrine clinic from December 2007 to December 2015 were included. They were investigated to determine the type of DSD (46,XY; 46, XX; or sex chromosome DSD) and where possible the precise aetiology based on clinical assessment, and hormonal, radiological and genetic investigations. SGA was defined as birthweight (BW) or length (BL) <10th centile according to the Audipog database. Statistical analysis was made using Epi-info7 and BiostaTGV.
Results: During the study period, 237 patients were referred with DSD, median (range) BW, BL and gestation: 3.1 (2.665) kg, 49.5 (3857) cm and 40 (2542) weeks. SGA was present in 83 (35%) infants, 45 (54%) of whom had BW <2500 g. The prevalence of SGA was higher in the groups with 46,XY DSD (47%) (n=48) and with sex chromosome DSD (44%) (n=7), than in the 46,XX DSD group (23.5%) (n=28) (P<0.01). In the 46,XY DSD group, the prevalence of SGA was particularly high in patients with syndromic DSD (89%) (n=8) and AR mutation-negative partial androgen insensitivity syndrome (54%) (n=27) (P<0.05). Within this latter group there was no difference in the prevalence of SGA according to the EMS score.
Conclusions: This study confirms the association between SGA and DSD, which appears especially strong in patients with idiopathic 46,XY DSD. The question remains as to whether there is a common genetic mechanism causing both DSD and SGA in 46,XY patients; or if the defect in prenatal exposure to androgens per se affects intrauterine growth.
10 - 12 Sep 2016
European Society for Paediatric Endocrinology