Johnston L B, Leger J, Savage M O, Clark A J, Czernichow P
Department of Endocrinology, St Bartholomew's and the Royal London School of Medicine and Dentistry, London, UK. l.b.johnston.qmw.ac.uk
Clin Endocrinol (Oxf). 1999 Oct;51(4):423-7. doi: 10.1046/j.1365-2265.1999.00803.x.
To investigate the association of genetic variation of the insulin-like growth factor-I (IGF-I) gene with birth size small for gestational age (SGA).
We have studied a cohort of 120 SGA patients and 147 appropriate for gestational age (AGA) controls from Haguenau, France.
PCR-SSCP analysis was performed to detect sequence variation in the coding region of the IGF-I gene. Microsatellite markers near the IGF-I gene (intronic and D12S78) were selected and amplified to perform further analysis by association studies.
A novel polymorphism in intron 2 was discovered, but allele-specific PCR analysis in the 120 SGA patients and 147 AGA controls found no association between this polymorphism and birth size SGA. Chi squared (chi2) analysis found no statistically significant association between the allele distribution of the microsatellite markers in the SGA subjects and the AGA controls. Power calculations estimate that the D12S78 marker has an 80% chance of detecting a 10-15% difference.
These studies suggest that genetic variation of IGF-I alone does not result in birth size small for gestational age in this population. Thus, if this gene influences fetal size, it plays only a minor role in a multifactorial disorder which involves other genetic and environmental factors.
研究胰岛素样生长因子-I（IGF-I）基因的遗传变异与小于胎龄儿（SGA）出生体重之间的关联。
我们对来自法国阿格诺的120例SGA患者和147例适于胎龄儿（AGA）对照进行了研究。
采用聚合酶链反应-单链构象多态性分析（PCR-SSCP）检测IGF-I基因编码区的序列变异。选择IGF-I基因附近的微卫星标记（内含子和D12S78）进行扩增，通过关联研究进一步分析。
在第2内含子中发现了一种新的多态性，但在120例SGA患者和147例AGA对照中进行的等位基因特异性PCR分析未发现该多态性与SGA出生体重之间存在关联。卡方（χ2）分析发现，SGA组和AGA对照组中微卫星标记的等位基因分布之间无统计学意义上的显著关联。效能计算估计，D12S78标记有80%的概率检测到10%-15%的差异。
这些研究表明，在该人群中，仅IGF-I基因的遗传变异不会导致小于胎龄儿出生体重。因此，如果该基因影响胎儿大小，它在涉及其他遗传和环境因素的多因素疾病中仅起次要作用。
