Background: It is well known that boys are heavier than girls at birth. Causes of this difference are thought to originate from the Y chromosome and as a result of androgen action. Although some studies showed that sex dimorphism in size at birth is dependent of fetal androgens, one study reported that it is not generated by action of androgens.
Objective and hypotheses: To determine birth weight (BW) of children in different aetiologies of disorder of sex development (DSD).
Method: Data regarding diagnosis, BW, karyotype and associated anomalies were gathered from the International DSD Registry (www.I-DSD.org). Gestational ages of cases were not accessible in the registry. BW below 2500 g was defined as low BW (LBW). Cases were evaluated according to disorder classification in I-DSD as disorders of gonadal development, androgen synthesis, androgen excess, androgen action, nonspecific disorder of undermasculinisation, Leydig cell defect, persistent Müllerian duct and others.
Results: Of 405 accessible cases with BW, 332 (82%) were 46,XY, 73 (18%) were 46,XX. LBW was detected in 98 cases (24.2%). Proportions of LBW were not statistically significant between 46,XX and 46,XY cases (9.6 and 15.6%, respectively, P=0.21). BWs were similar in each disorder group between 46,XX and 46,XY cases in both BW ≥2500 g and LBW groups. When BWs were compared between disorder subgroups, no statistically significant differences were detected. Among those children with known gestational age (n=86) BW was expressed as SDS according to national standards for each country. Analysis of these BWSDS in the different diagnostic groups did not reveal any significant differences between 46,XX and 46,XY cases. Other anomalies beyond the genitourinary system were more frequent in LBW cases (46.9 and 13.7%, respectively, P=0.0001) and in 46,XY group (27.2 and 6.8%, respectively, P=0.0001).
Conclusion: Size at birth in both karyotypes seems unlikely to be dependent on fetal androgens. Syndromal forms of DSD with multi-system involvement are more likely to have a LBW.
01 - 03 Oct 2015
European Society for Paediatric Endocrinology