A 49,XXXXX girl is reported. The most typical features of the patient are: severe mental retardation, serious dental anomalies, various anomalies of the bones, and a high rate of gonadotropins. The few similar cases so far described are reviewed to aid in delineation of this rare syndrome. The implications of Lyon's hypothesis on X-aneuploidies are also discussed. © 1979 Springer-Verlag.
Archidiacono, N., Rocchi, M., Valente, M., & Filippi, G. (1979). X pentasomy: A case and review. Human Genetics, 52(1), 69–77. https://doi.org/10.1007/BF00284599