- Novel insertion frameshift mutation of the LH receptor gene: problematic clinical distinction of Leydig cell hypoplasia from enzyme defects primarily affecting testosterone biosynthesis. Richter-Unruh, A., Korsch, E., Hiort, O., Holterhus, P.M., Themmen, A.P., Wudy, S.A. Eur. J. Endocrinol. (2005)