Divakaran Anjith, Narayanaswamy Janardhanan C, Kalmady Sunil V, Narayan Vidya, Rao Naren P, Venkatasubramanian Ganesan
Department of Psychiatry and Translational Psychiatry Laboratory, Neurobiology Research Center, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India.
Indian J Psychol Med. 2012 Oct;34(4):355-9. doi: 10.4103/0253-7176.108220.
The differences in digit ratio are proposed to arise due to differential effects of sex steroids on the growth of finger bones. In this study, we sought to examine the sex differences and the influence of family history of psychosis on digit ratio in patients with schizophrenia compared to matched healthy controls (HCs).
Digit ratio (2D: 4D) was examined for a large sample of schizophrenia patients (n=200) and HC (n=177) to evaluate the potential effects of family history.
The right hand 2D: 4D digit ratio was lesser in schizophrenia patients compared to HC (0.97±0.05 vs 0.98±0.04, t=2.2, P=0.02). There was a significant difference in the right hand 2D: 4D digit ratio of female patients with schizophrenia when compared to female HCs (0.96±0.05 vs 0.98±0.03, t=2.1, P=0.03) while males showed no such difference on either hands. On the contrary, family history‑positive males showed a significantly greater digit ratio for the left hand (FH present (0.99±0.04) vs HC (0.97±0.04), t=2.15, P=0.03), while there was no difference between family history‑positive females and HC.
Overall, in patients, reversal of expected "directionality" in digit ratio was observed in our study with greater left 2D: 4D in male patients having a family history of schizophrenia being a novel finding. Reversal of sexual dimorphism has been linked to the pathogenesis of schizophrenia. It is possible that such reversal might have a putative genetic basis, perhaps only in men with schizophrenia.
手指比例的差异被认为是由于性类固醇对手指骨骼生长的不同影响而产生的。在本研究中，我们试图检验精神分裂症患者与匹配的健康对照者（HCs）相比，手指比例的性别差异以及精神病家族史对其的影响。
对大量精神分裂症患者样本（n = 200）和HCs样本（n = 177）进行手指比例（2D:4D）检测，以评估家族史的潜在影响。
与HCs相比，精神分裂症患者右手的2D:4D手指比例较小（0.97±0.05对0.98±0.04，t = 2.2，P = 0.02）。与女性HCs相比，女性精神分裂症患者右手的2D:4D手指比例存在显著差异（0.96±0.05对0.98±0.03，t = 2.1，P = 0.03），而男性双手均未显示出此类差异。相反，家族史阳性的男性左手手指比例显著更高（家族史阳性者为0.99±0.04，HCs为0.97±0.04，t = 2.15，P = 0.03），而家族史阳性的女性与HCs之间没有差异。
总体而言，在患者中，我们的研究观察到手指比例预期的“方向性”发生了逆转，精神分裂症家族史男性患者左手2D:4D比例更高是一个新发现。性二态性的逆转与精神分裂症的发病机制有关。这种逆转可能有一个假定的遗传基础，也许仅存在于精神分裂症男性患者中。
