Alvesalo L, Tammisalo E
Am J Hum Genet. 1981 May;33(3):464-9.
Enamel thicknesses in 45,X females', their male and female relatives', and population control males' and females' permanent tooth crowns were determined from radiographs. The results showed that the enamel layer in both maxillary first incisors and canines of 45,X females is definitely thinner than that of control males or females. Enamel in control males' and females' teeth was about equal in size. The distance between mesial and distal dentino-enamel junctions or the thickness of "dentin" was similar in 45,X females' and in control females' teeth, but definitely smaller than in control males' teeth. These findings show that in the presence of the second sex-chromosome in the chromosome complement, whether X or Y, there is a definite and equal increase in the amount of enamel. On the other hand, in the presence of the Y chromosome in the chromosome complement, relative to the second X chromosome, there is a definite increase in the thickness of the dentin. The results of earlier studies have indicated a direct growth-promoting effect of the sex chromosomes on tooth growth, and that the effect of X and Y chromosomes is different. The present results suggest that the influence of the X- and Y-chromosome gene(s) on amelogenesis is the same in quantitative terms but different in relation to the determination of the distance between dentino-enamel junctions; the Y chromosome is more effective than the X chromosome in that respect. It is postulated that this size-increasing effect of the Y-chromosome gene(s) might result from its profound effect on cell proliferations.
通过X光片测定了45,X女性及其男性和女性亲属以及作为对照的普通男性和女性恒牙牙冠的牙釉质厚度。结果显示，45,X女性上颌第一恒切牙和尖牙的牙釉质层明显比对照男性或女性的薄。对照男性和女性牙齿的牙釉质大小大致相等。45,X女性和对照女性牙齿中近中与远中牙本质-牙釉质交界处之间的距离或“牙本质”厚度相似，但肯定小于对照男性牙齿。这些发现表明，在染色体组中存在第二条性染色体时，无论它是X还是Y，牙釉质的量都会有确定且相等的增加。另一方面，在染色体组中存在Y染色体时，相对于第二条X染色体，牙本质的厚度会有确定的增加。早期研究结果表明性染色体对牙齿生长有直接的促进生长作用，而且X和Y染色体的作用不同。目前的结果表明，X和Y染色体基因对釉质形成的影响在数量上是相同的，但在确定牙本质-牙釉质交界处之间的距离方面有所不同；在这方面，Y染色体比X染色体更有效。据推测，Y染色体基因的这种增大尺寸的作用可能是由于其对细胞增殖有深远影响。
