Multidisciplinary Approach to the Child with Sex Chromosomal Mosaicism Including a Y-Containing Cell Line.

Children born with sex chromosomal mosaicism including material derived from the Y chromosome may present with a broad phenotypical spectrum. Both boys and girls can present with Turner features and functional health problems typically associated with Turner syndrome, but the presence of Y-chromosomal material can modify some aspects of the condition. We retrospectively analyzed the results of our cohort of 21 individuals (14 boys, 7 girls) with sex chromosomal mosaicism including Y-derived material followed at Ghent University Hospital according to our local multidisciplinary Turner surveillance protocol. Results were compared with literature data, focusing on similarities and differences between girls and boys with this condition. Age at diagnosis was lower in boys compared to girls but the difference was not significant. Short stature is a key feature of the condition both in girls and boys, but skeletal maturation may be different between groups. The effects of growth-hormone therapy remain unclear. Cardiac (33%), ear-nose- throat (ENT) (77.8%) and renal (28.6%) problems were as prevalent in boys as in girls from our cohort, and did not differ from literature data. In line with literature reports, a significant difference in the presence of premalignant germ cell tumors between males (0%) and females (42.9%) was found (p = 0.026). Taken together, this study demonstrates the similarities between girls with Turner syndrome and children with sex chromosomal mosaicism including Y-derived material, regardless of the child's gender. Nowadays, girls with Turner syndrome are offered a dedicated multidisciplinary follow-up in many centers. We advocate a similar follow-up program for all children who have sex chromosomal mosaicism that includes Y-derived material, with special attention to growth, cardiac and ear-nose-throat problems, gonadal function and malignancies.