Silva-Ramos M, Oliveira J M, Cabeda J M, Reis A, Soares J, Pimenta A
Department of Urology, Santo Antonio General Hospital, Porto, Portugal.
Int Braz J Urol. 2006 May-Jun;32(3):330-4; discussion 335. doi: 10.1590/s1677-55382006000300014.
We examined the significance of the CAG repeat polymorphism in the pathogenesis of cryptorchidism.
Genomic deoxyribonucleic acid (DNA) was extracted from blood samples from 42 cryptorchid boys and from 31 non-cryptorchid control subjects. In the cryptorchid group, 7 had bilateral cryptorchidism and 6 had patent processus vaginalis in the contralateral side. To determine the number of CAG repeats, the DNA was amplified by polymerase chain reaction and sequenced.
The mean CAG repeat length in the AR gene was 22.5 (range 16 to 28) in patients and 21.5 (range 17 to 26) in controls (non-significant). Patients with bilateral cryptorchidism had a mean length of 24.3 (range 21 to 26) and patients with unilateral cryptorchidism and patent processus vaginalis in the contra lateral side had a mean of 25.2 (range 21 to 28), which was statistically different from controls (p = 0.015 and p = 0.005 respectively).
CAG repeat length of the AR gene does not seem to play a major role in patients with unilateral cryptorchidism. However, in patients with bilateral undescended testis, a less functional androgen receptor through a longer polyglutamine chain may have a role in its pathogenesis. In the same way, patients with unilateral cryptorchidism a contralateral patent processus vaginalis have longer CAG repeats that might be responsible for a slower testicular descent and incomplete closure of the processus vaginalis.
我们研究了CAG重复多态性在隐睾症发病机制中的意义。
从42名隐睾症男孩和31名非隐睾症对照者的血液样本中提取基因组脱氧核糖核酸（DNA）。在隐睾症组中，7例为双侧隐睾症，6例对侧鞘状突未闭。为了确定CAG重复序列的数量，通过聚合酶链反应对DNA进行扩增并测序。
患者雄激素受体（AR）基因中CAG重复序列的平均长度为22.5（范围16至28），对照组为21.5（范围17至26）（无统计学意义）。双侧隐睾症患者的平均长度为24.3（范围21至26），单侧隐睾症且对侧鞘状突未闭的患者平均长度为25.2（范围21至28），与对照组相比有统计学差异（分别为p = 0.015和p = 0.005）。
AR基因的CAG重复序列长度在单侧隐睾症患者中似乎不起主要作用。然而，在双侧睾丸未降的患者中，通过更长的聚谷氨酰胺链导致功能较弱的雄激素受体可能在其发病机制中起作用。同样，单侧隐睾症且对侧鞘状突未闭的患者CAG重复序列更长，这可能导致睾丸下降缓慢和鞘状突未完全闭合。
